Class Component
- java.lang.Object
-
- java.awt.Component
- All Implemented Interfaces:
-
ImageObserver
,MenuContainer
,Serializable
- Direct Known Subclasses:
-
Button
,Canvas
,Checkbox
,Choice
,Container
,Label
,List
,Scrollbar
,TextComponent
public abstract class Component extends Object implements ImageObserver, MenuContainer, Serializable
A component is an object having a graphical representation that can be displayed on the screen and that can interact with the user. Examples of components are the buttons, checkboxes, and scrollbars of a typical graphical user interface.
The Component
class is the abstract superclass of the nonmenu-related Abstract Window Toolkit components. Class Component
can also be extended directly to create a lightweight component. A lightweight component is a component that is not associated with a native window. On the contrary, a heavyweight component is associated with a native window. The isLightweight()
method may be used to distinguish between the two kinds of the components.
Lightweight and heavyweight components may be mixed in a single component hierarchy. However, for correct operating of such a mixed hierarchy of components, the whole hierarchy must be valid. When the hierarchy gets invalidated, like after changing the bounds of components, or adding/removing components to/from containers, the whole hierarchy must be validated afterwards by means of the Container.validate()
method invoked on the top-most invalid container of the hierarchy.
Serialization
It is important to note that only AWT listeners which conform to theSerializable
protocol will be saved when the object is stored. If an AWT object has listeners that aren't marked serializable, they will be dropped at writeObject
time. Developers will need, as always, to consider the implications of making an object serializable. One situation to watch out for is this: import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements ActionListener, Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); MyApp() { // Oops, now aButton has a listener with a reference // to bigOne! aButton.addActionListener(this); } public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } }In this example, serializing
aButton
by itself will cause MyApp
and everything it refers to to be serialized as well. The problem is that the listener is serializable by coincidence, not by design. To separate the decisions about MyApp
and the ActionListener
being serializable one can use a nested class, as in the following example: import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements java.io.Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); static class MyActionListener implements ActionListener { public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } } MyApp() { aButton.addActionListener(new MyActionListener()); } }
Note: For more information on the paint mechanisms utilized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
For details on the focus subsystem, see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.
- See Also:
- Serialized Form
Nested Class Summary
Modifier and Type | Class | Description |
---|---|---|
protected class | Component.AccessibleAWTComponent | Inner class of Component used to provide default support for accessibility. |
static class | Component.BaselineResizeBehavior | Enumeration of the common ways the baseline of a component can change as the size changes. |
protected class | Component.BltBufferStrategy | Inner class for blitting offscreen surfaces to a component. |
protected class | Component.FlipBufferStrategy | Inner class for flipping buffers on a component. |
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected AccessibleContext | accessibleContext | The |
static float | BOTTOM_ALIGNMENT | Ease-of-use constant for |
static float | CENTER_ALIGNMENT | Ease-of-use constant for |
static float | LEFT_ALIGNMENT | Ease-of-use constant for |
static float | RIGHT_ALIGNMENT | Ease-of-use constant for |
static float | TOP_ALIGNMENT | Ease-of-use constant for |
Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | Component() | Constructs a new component. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
boolean | action(Event evt,
Object what) | Deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events. |
void | add(PopupMenu popup) | Adds the specified popup menu to the component. |
void | addComponentListener(ComponentListener l) | Adds the specified component listener to receive component events from this component. |
void | addFocusListener(FocusListener l) | Adds the specified focus listener to receive focus events from this component when this component gains input focus. |
void | addHierarchyBoundsListener(HierarchyBoundsListener l) | Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes. |
void | addHierarchyListener(HierarchyListener l) | Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes. |
void | addInputMethodListener(InputMethodListener l) | Adds the specified input method listener to receive input method events from this component. |
void | addKeyListener(KeyListener l) | Adds the specified key listener to receive key events from this component. |
void | addMouseListener(MouseListener l) | Adds the specified mouse listener to receive mouse events from this component. |
void | addMouseMotionListener(MouseMotionListener l) | Adds the specified mouse motion listener to receive mouse motion events from this component. |
void | addMouseWheelListener(MouseWheelListener l) | Adds the specified mouse wheel listener to receive mouse wheel events from this component. |
void | addNotify() | Makes this |
void | addPropertyChangeListener(PropertyChangeListener listener) | Adds a PropertyChangeListener to the listener list. |
void | addPropertyChangeListener(String propertyName,
PropertyChangeListener listener) | Adds a PropertyChangeListener to the listener list for a specific property. |
void | applyComponentOrientation(ComponentOrientation orientation) | Sets the |
boolean | areFocusTraversalKeysSet(int id) | Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component. |
Rectangle | bounds() | Deprecated. As of JDK version 1.1, replaced by getBounds() . |
int | checkImage(Image image,
int width,
int height,
ImageObserver observer) | Returns the status of the construction of a screen representation of the specified image. |
int | checkImage(Image image,
ImageObserver observer) | Returns the status of the construction of a screen representation of the specified image. |
protected AWTEvent | coalesceEvents(AWTEvent existingEvent,
AWTEvent newEvent) | Potentially coalesce an event being posted with an existing event. |
boolean | contains(int x,
int y) | Checks whether this component "contains" the specified point, where |
boolean | contains(Point p) | Checks whether this component "contains" the specified point, where the point's x and y coordinates are defined to be relative to the coordinate system of this component. |
Image | createImage(int width,
int height) | Creates an off-screen drawable image to be used for double buffering. |
Image | createImage(ImageProducer producer) | Creates an image from the specified image producer. |
VolatileImage | createVolatileImage(int width,
int height) | Creates a volatile off-screen drawable image to be used for double buffering. |
VolatileImage | createVolatileImage(int width,
int height,
ImageCapabilities caps) | Creates a volatile off-screen drawable image, with the given capabilities. |
void | deliverEvent(Event e) | Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e) . |
void | disable() | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
protected void | disableEvents(long eventsToDisable) | Disables the events defined by the specified event mask parameter from being delivered to this component. |
void | dispatchEvent(AWTEvent e) | Dispatches an event to this component or one of its sub components. |
void | doLayout() | Prompts the layout manager to lay out this component. |
void | enable() | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
void | enable(boolean b) | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
protected void | enableEvents(long eventsToEnable) | Enables the events defined by the specified event mask parameter to be delivered to this component. |
void | enableInputMethods(boolean enable) | Enables or disables input method support for this component. |
protected void | firePropertyChange(String propertyName,
boolean oldValue,
boolean newValue) | Support for reporting bound property changes for boolean properties. |
void | firePropertyChange(String propertyName,
byte oldValue,
byte newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName,
char oldValue,
char newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName,
double oldValue,
double newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName,
float oldValue,
float newValue) | Reports a bound property change. |
protected void | firePropertyChange(String propertyName,
int oldValue,
int newValue) | Support for reporting bound property changes for integer properties. |
void | firePropertyChange(String propertyName,
long oldValue,
long newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName,
short oldValue,
short newValue) | Reports a bound property change. |
protected void | firePropertyChange(String propertyName,
Object oldValue,
Object newValue) | Support for reporting bound property changes for Object properties. |
AccessibleContext | getAccessibleContext() | Gets the |
float | getAlignmentX() | Returns the alignment along the x axis. |
float | getAlignmentY() | Returns the alignment along the y axis. |
Color | getBackground() | Gets the background color of this component. |
int | getBaseline(int width,
int height) | Returns the baseline. |
Component.BaselineResizeBehavior | getBaselineResizeBehavior() | Returns an enum indicating how the baseline of the component changes as the size changes. |
Rectangle | getBounds() | Gets the bounds of this component in the form of a |
Rectangle | getBounds(Rectangle rv) | Stores the bounds of this component into "return value" rv and return rv. |
ColorModel | getColorModel() | Gets the instance of |
Component | getComponentAt(int x,
int y) | Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component. |
Component | getComponentAt(Point p) | Returns the component or subcomponent that contains the specified point. |
ComponentListener[] | getComponentListeners() | Returns an array of all the component listeners registered on this component. |
ComponentOrientation | getComponentOrientation() | Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component. |
Cursor | getCursor() | Gets the cursor set in the component. |
DropTarget | getDropTarget() | Gets the |
Container | getFocusCycleRootAncestor() | Returns the Container which is the focus cycle root of this Component's focus traversal cycle. |
FocusListener[] | getFocusListeners() | Returns an array of all the focus listeners registered on this component. |
Set<AWTKeyStroke> | getFocusTraversalKeys(int id) | Returns the Set of focus traversal keys for a given traversal operation for this Component. |
boolean | getFocusTraversalKeysEnabled() | Returns whether focus traversal keys are enabled for this Component. |
Font | getFont() | Gets the font of this component. |
FontMetrics | getFontMetrics(Font font) | Gets the font metrics for the specified font. |
Color | getForeground() | Gets the foreground color of this component. |
Graphics | getGraphics() | Creates a graphics context for this component. |
GraphicsConfiguration | getGraphicsConfiguration() | Gets the |
int | getHeight() | Returns the current height of this component. |
HierarchyBoundsListener[] | getHierarchyBoundsListeners() | Returns an array of all the hierarchy bounds listeners registered on this component. |
HierarchyListener[] | getHierarchyListeners() | Returns an array of all the hierarchy listeners registered on this component. |
boolean | getIgnoreRepaint() | |
InputContext | getInputContext() | Gets the input context used by this component for handling the communication with input methods when text is entered in this component. |
InputMethodListener[] | getInputMethodListeners() | Returns an array of all the input method listeners registered on this component. |
InputMethodRequests | getInputMethodRequests() | Gets the input method request handler which supports requests from input methods for this component. |
KeyListener[] | getKeyListeners() | Returns an array of all the key listeners registered on this component. |
<T extends EventListener> | getListeners(Class<T> listenerType) | Returns an array of all the objects currently registered as |
Locale | getLocale() | Gets the locale of this component. |
Point | getLocation() | Gets the location of this component in the form of a point specifying the component's top-left corner. |
Point | getLocation(Point rv) | Stores the x,y origin of this component into "return value" rv and return rv. |
Point | getLocationOnScreen() | Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space. |
Dimension | getMaximumSize() | Gets the maximum size of this component. |
Dimension | getMinimumSize() | Gets the minimum size of this component. |
MouseListener[] | getMouseListeners() | Returns an array of all the mouse listeners registered on this component. |
MouseMotionListener[] | getMouseMotionListeners() | Returns an array of all the mouse motion listeners registered on this component. |
Point | getMousePosition() | Returns the position of the mouse pointer in this |
MouseWheelListener[] | getMouseWheelListeners() | Returns an array of all the mouse wheel listeners registered on this component. |
String | getName() | Gets the name of the component. |
Container | getParent() | Gets the parent of this component. |
Dimension | getPreferredSize() | Gets the preferred size of this component. |
PropertyChangeListener[] | getPropertyChangeListeners() | Returns an array of all the property change listeners registered on this component. |
PropertyChangeListener[] | getPropertyChangeListeners(String propertyName) | Returns an array of all the listeners which have been associated with the named property. |
Dimension | getSize() | Returns the size of this component in the form of a |
Dimension | getSize(Dimension rv) | Stores the width/height of this component into "return value" rv and return rv. |
Toolkit | getToolkit() | Gets the toolkit of this component. |
Object | getTreeLock() | Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations. |
int | getWidth() | Returns the current width of this component. |
int | getX() | Returns the current x coordinate of the components origin. |
int | getY() | Returns the current y coordinate of the components origin. |
boolean | gotFocus(Event evt,
Object what) | Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent). |
boolean | handleEvent(Event evt) | Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent). |
boolean | hasFocus() | Returns |
void | hide() | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
boolean | imageUpdate(Image img,
int infoflags,
int x,
int y,
int w,
int h) | Repaints the component when the image has changed. |
boolean | inside(int x,
int y) | Deprecated. As of JDK version 1.1, replaced by contains(int, int). |
void | invalidate() | Invalidates this component and its ancestors. |
boolean | isBackgroundSet() | Returns whether the background color has been explicitly set for this Component. |
boolean | isCursorSet() | Returns whether the cursor has been explicitly set for this Component. |
boolean | isDisplayable() | Determines whether this component is displayable. |
boolean | isDoubleBuffered() | Returns true if this component is painted to an offscreen image ("buffer") that's copied to the screen later. |
boolean | isEnabled() | Determines whether this component is enabled. |
boolean | isFocusable() | Returns whether this Component can be focused. |
boolean | isFocusCycleRoot(Container container) | Returns whether the specified Container is the focus cycle root of this Component's focus traversal cycle. |
boolean | isFocusOwner() | Returns |
boolean | isFocusTraversable() | Deprecated. As of 1.4, replaced by isFocusable() . |
boolean | isFontSet() | Returns whether the font has been explicitly set for this Component. |
boolean | isForegroundSet() | Returns whether the foreground color has been explicitly set for this Component. |
boolean | isLightweight() | A lightweight component doesn't have a native toolkit peer. |
boolean | isMaximumSizeSet() | Returns true if the maximum size has been set to a non- |
boolean | isMinimumSizeSet() | Returns whether or not |
boolean | isOpaque() | Returns true if this component is completely opaque, returns false by default. |
boolean | isPreferredSizeSet() | Returns true if the preferred size has been set to a non- |
boolean | isShowing() | Determines whether this component is showing on screen. |
boolean | isValid() | Determines whether this component is valid. |
boolean | isVisible() | Determines whether this component should be visible when its parent is visible. |
boolean | keyDown(Event evt,
int key) | Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
boolean | keyUp(Event evt,
int key) | Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
void | layout() | Deprecated. As of JDK version 1.1, replaced by doLayout() . |
void | list() | Prints a listing of this component to the standard system output stream |
void | list(PrintStream out) | Prints a listing of this component to the specified output stream. |
void | list(PrintStream out,
int indent) | Prints out a list, starting at the specified indentation, to the specified print stream. |
void | list(PrintWriter out) | Prints a listing to the specified print writer. |
void | list(PrintWriter out,
int indent) | Prints out a list, starting at the specified indentation, to the specified print writer. |
Component | locate(int x,
int y) | Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int). |
Point | location() | Deprecated. As of JDK version 1.1, replaced by getLocation() . |
boolean | lostFocus(Event evt,
Object what) | Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent). |
Dimension | minimumSize() | Deprecated. As of JDK version 1.1, replaced by getMinimumSize() . |
boolean | mouseDown(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseDrag(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent). |
boolean | mouseEnter(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseExit(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseMove(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent). |
boolean | mouseUp(Event evt,
int x,
int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
void | move(int x,
int y) | Deprecated. As of JDK version 1.1, replaced by setLocation(int, int) . |
void | nextFocus() | Deprecated. As of JDK version 1.1, replaced by transferFocus(). |
void | paint(Graphics g) | Paints this component. |
void | paintAll(Graphics g) | Paints this component and all of its subcomponents. |
protected String | paramString() | Returns a string representing the state of this component. |
boolean | postEvent(Event e) | Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent). |
Dimension | preferredSize() | Deprecated. As of JDK version 1.1, replaced by getPreferredSize() . |
boolean | prepareImage(Image image,
int width,
int height,
ImageObserver observer) | Prepares an image for rendering on this component at the specified width and height. |
boolean | prepareImage(Image image,
ImageObserver observer) | Prepares an image for rendering on this component. |
void | print(Graphics g) | Prints this component. |
void | printAll(Graphics g) | Prints this component and all of its subcomponents. |
protected void | processComponentEvent(ComponentEvent e) | Processes component events occurring on this component by dispatching them to any registered |
protected void | processEvent(AWTEvent e) | Processes events occurring on this component. |
protected void | processFocusEvent(FocusEvent e) | Processes focus events occurring on this component by dispatching them to any registered |
protected void | processHierarchyBoundsEvent(HierarchyEvent e) | Processes hierarchy bounds events occurring on this component by dispatching them to any registered |
protected void | processHierarchyEvent(HierarchyEvent e) | Processes hierarchy events occurring on this component by dispatching them to any registered |
protected void | processInputMethodEvent(InputMethodEvent e) | Processes input method events occurring on this component by dispatching them to any registered |
protected void | processKeyEvent(KeyEvent e) | Processes key events occurring on this component by dispatching them to any registered |
protected void | processMouseEvent(MouseEvent e) | Processes mouse events occurring on this component by dispatching them to any registered |
protected void | processMouseMotionEvent(MouseEvent e) | Processes mouse motion events occurring on this component by dispatching them to any registered |
protected void | processMouseWheelEvent(MouseWheelEvent e) | Processes mouse wheel events occurring on this component by dispatching them to any registered |
void | remove(MenuComponent popup) | Removes the specified popup menu from the component. |
void | removeComponentListener(ComponentListener l) | Removes the specified component listener so that it no longer receives component events from this component. |
void | removeFocusListener(FocusListener l) | Removes the specified focus listener so that it no longer receives focus events from this component. |
void | removeHierarchyBoundsListener(HierarchyBoundsListener l) | Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component. |
void | removeHierarchyListener(HierarchyListener l) | Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component. |
void | removeInputMethodListener(InputMethodListener l) | Removes the specified input method listener so that it no longer receives input method events from this component. |
void | removeKeyListener(KeyListener l) | Removes the specified key listener so that it no longer receives key events from this component. |
void | removeMouseListener(MouseListener l) | Removes the specified mouse listener so that it no longer receives mouse events from this component. |
void | removeMouseMotionListener(MouseMotionListener l) | Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component. |
void | removeMouseWheelListener(MouseWheelListener l) | Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component. |
void | removeNotify() | Makes this |
void | removePropertyChangeListener(PropertyChangeListener listener) | Removes a PropertyChangeListener from the listener list. |
void | removePropertyChangeListener(String propertyName,
PropertyChangeListener listener) | Removes a |
void | repaint() | Repaints this component. |
void | repaint(int x,
int y,
int width,
int height) | Repaints the specified rectangle of this component. |
void | repaint(long tm) | Repaints the component. |
void | repaint(long tm,
int x,
int y,
int width,
int height) | Repaints the specified rectangle of this component within |
void | requestFocus() | Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. |
protected boolean | requestFocus(boolean temporary) | Requests that this |
protected boolean | requestFocus(boolean temporary,
FocusEvent.Cause cause) | Requests by the reason of |
void | requestFocus(FocusEvent.Cause cause) | Requests by the reason of |
boolean | requestFocusInWindow() | Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. |
protected boolean | requestFocusInWindow(boolean temporary) | Requests that this |
boolean | requestFocusInWindow(FocusEvent.Cause cause) | Requests by the reason of |
void | reshape(int x,
int y,
int width,
int height) | Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int) . |
void | resize(int width,
int height) | Deprecated. As of JDK version 1.1, replaced by setSize(int, int) . |
void | resize(Dimension d) | Deprecated. As of JDK version 1.1, replaced by setSize(Dimension) . |
void | revalidate() | Revalidates the component hierarchy up to the nearest validate root. |
void | setBackground(Color c) | Sets the background color of this component. |
void | setBounds(int x,
int y,
int width,
int height) | Moves and resizes this component. |
void | setBounds(Rectangle r) | Moves and resizes this component to conform to the new bounding rectangle |
void | setComponentOrientation(ComponentOrientation o) | Sets the language-sensitive orientation that is to be used to order the elements or text within this component. |
void | setCursor(Cursor cursor) | Sets the cursor image to the specified cursor. |
void | setDropTarget(DropTarget dt) | Associate a |
void | setEnabled(boolean b) | Enables or disables this component, depending on the value of the parameter |
void | setFocusable(boolean focusable) | Sets the focusable state of this Component to the specified value. |
void | setFocusTraversalKeys(int id,
Set<? extends AWTKeyStroke> keystrokes) | Sets the focus traversal keys for a given traversal operation for this Component. |
void | setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled) | Sets whether focus traversal keys are enabled for this Component. |
void | setFont(Font f) | Sets the font of this component. |
void | setForeground(Color c) | Sets the foreground color of this component. |
void | setIgnoreRepaint(boolean ignoreRepaint) | Sets whether or not paint messages received from the operating system should be ignored. |
void | setLocale(Locale l) | Sets the locale of this component. |
void | setLocation(int x,
int y) | Moves this component to a new location. |
void | setLocation(Point p) | Moves this component to a new location. |
void | setMaximumSize(Dimension maximumSize) | Sets the maximum size of this component to a constant value. |
void | setMinimumSize(Dimension minimumSize) | Sets the minimum size of this component to a constant value. |
void | setMixingCutoutShape(Shape shape) | Sets a 'mixing-cutout' shape for this lightweight component. |
void | setName(String name) | Sets the name of the component to the specified string. |
void | setPreferredSize(Dimension preferredSize) | Sets the preferred size of this component to a constant value. |
void | setSize(int width,
int height) | Resizes this component so that it has width |
void | setSize(Dimension d) | Resizes this component so that it has width |
void | setVisible(boolean b) | Shows or hides this component depending on the value of parameter |
void | show() | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
void | show(boolean b) | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
Dimension | size() | Deprecated. As of JDK version 1.1, replaced by getSize() . |
String | toString() | Returns a string representation of this component and its values. |
void | transferFocus() | Transfers the focus to the next component, as though this Component were the focus owner. |
void | transferFocusBackward() | Transfers the focus to the previous component, as though this Component were the focus owner. |
void | transferFocusUpCycle() | Transfers the focus up one focus traversal cycle. |
void | update(Graphics g) | Updates this component. |
void | validate() | Validates this component. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Field Detail
TOP_ALIGNMENT
public static final float TOP_ALIGNMENT
Ease-of-use constant for getAlignmentY()
. Specifies an alignment to the top of the component.
- See Also:
-
getAlignmentY()
, Constant Field Values
CENTER_ALIGNMENT
public static final float CENTER_ALIGNMENT
Ease-of-use constant for getAlignmentY
and getAlignmentX
. Specifies an alignment to the center of the component
- See Also:
-
getAlignmentX()
,getAlignmentY()
, Constant Field Values
BOTTOM_ALIGNMENT
public static final float BOTTOM_ALIGNMENT
Ease-of-use constant for getAlignmentY
. Specifies an alignment to the bottom of the component.
- See Also:
-
getAlignmentY()
, Constant Field Values
LEFT_ALIGNMENT
public static final float LEFT_ALIGNMENT
Ease-of-use constant for getAlignmentX
. Specifies an alignment to the left side of the component.
- See Also:
-
getAlignmentX()
, Constant Field Values
RIGHT_ALIGNMENT
public static final float RIGHT_ALIGNMENT
Ease-of-use constant for getAlignmentX
. Specifies an alignment to the right side of the component.
- See Also:
-
getAlignmentX()
, Constant Field Values
accessibleContext
protected AccessibleContext accessibleContext
The AccessibleContext
associated with this Component
.
Constructor Detail
Component
protected Component()
Constructs a new component. Class Component
can be extended directly to create a lightweight component that does not utilize an opaque native window. A lightweight component must be hosted by a native container somewhere higher up in the component tree (for example, by a Frame
object).
Method Detail
getName
public String getName()
Gets the name of the component.
- Returns:
- this component's name
- Since:
- 1.1
- See Also:
setName(java.lang.String)
setName
public void setName(String name)
Sets the name of the component to the specified string.
- Parameters:
-
name
- the string that is to be this component's name - Since:
- 1.1
- See Also:
getName()
getParent
public Container getParent()
Gets the parent of this component.
- Returns:
- the parent container of this component
- Since:
- 1.0
setDropTarget
public void setDropTarget(DropTarget dt)
Associate a DropTarget
with this component. The Component
will receive drops only if it is enabled.
- Parameters:
-
dt
- The DropTarget - See Also:
isEnabled()
getDropTarget
public DropTarget getDropTarget()
Gets the DropTarget
associated with this Component
.
- Returns:
- the drop target
getGraphicsConfiguration
public GraphicsConfiguration getGraphicsConfiguration()
Gets the GraphicsConfiguration
associated with this Component
. If the Component
has not been assigned a specific GraphicsConfiguration
, the GraphicsConfiguration
of the Component
object's top-level container is returned. If the Component
has been created, but not yet added to a Container
, this method returns null
.
- Returns:
- the
GraphicsConfiguration
used by thisComponent
ornull
- Since:
- 1.3
getTreeLock
public final Object getTreeLock()
Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations.
- Returns:
- this component's locking object
getToolkit
public Toolkit getToolkit()
Gets the toolkit of this component. Note that the frame that contains a component controls which toolkit is used by that component. Therefore if the component is moved from one frame to another, the toolkit it uses may change.
- Returns:
- the toolkit of this component
- Since:
- 1.0
isValid
public boolean isValid()
Determines whether this component is valid. A component is valid when it is correctly sized and positioned within its parent container and all its children are also valid. In order to account for peers' size requirements, components are invalidated before they are first shown on the screen. By the time the parent container is fully realized, all its components will be valid.
- Returns:
-
true
if the component is valid,false
otherwise - Since:
- 1.0
- See Also:
-
validate()
,invalidate()
isDisplayable
public boolean isDisplayable()
Determines whether this component is displayable. A component is displayable when it is connected to a native screen resource.
A component is made displayable either when it is added to a displayable containment hierarchy or when its containment hierarchy is made displayable. A containment hierarchy is made displayable when its ancestor window is either packed or made visible.
A component is made undisplayable either when it is removed from a displayable containment hierarchy or when its containment hierarchy is made undisplayable. A containment hierarchy is made undisplayable when its ancestor window is disposed.
- Returns:
-
true
if the component is displayable,false
otherwise - Since:
- 1.2
- See Also:
-
Container.add(Component)
,Window.pack()
,Window.show()
,Container.remove(Component)
,Window.dispose()
isVisible
public boolean isVisible()
Determines whether this component should be visible when its parent is visible. Components are initially visible, with the exception of top level components such as Frame
objects.
- Returns:
-
true
if the component is visible,false
otherwise - Since:
- 1.0
- See Also:
setVisible(boolean)
getMousePosition
public Point getMousePosition() throws HeadlessException
Returns the position of the mouse pointer in this Component
's coordinate space if the Component
is directly under the mouse pointer, otherwise returns null
. If the Component
is not showing on the screen, this method returns null
even if the mouse pointer is above the area where the Component
would be displayed. If the Component
is partially or fully obscured by other Component
s or native windows, this method returns a non-null value only if the mouse pointer is located above the unobscured part of the Component
.
For Container
s it returns a non-null value if the mouse is above the Container
itself or above any of its descendants. Use Container.getMousePosition(boolean)
if you need to exclude children.
Sometimes the exact mouse coordinates are not important, and the only thing that matters is whether a specific Component
is under the mouse pointer. If the return value of this method is null
, mouse pointer is not directly above the Component
.
- Returns:
- mouse coordinates relative to this
Component
, or null - Throws:
-
HeadlessException
- if GraphicsEnvironment.isHeadless() returns true - Since:
- 1.5
- See Also:
-
isShowing()
,Container.getMousePosition(boolean)
isShowing
public boolean isShowing()
Determines whether this component is showing on screen. This means that the component must be visible, and it must be in a container that is visible and showing.
Note: sometimes there is no way to detect whether the Component
is actually visible to the user. This can happen when:
- the component has been added to a visible
ScrollPane
but theComponent
is not currently in the scroll pane's view port. - the
Component
is obscured by anotherComponent
orContainer
.
- Returns:
-
true
if the component is showing,false
otherwise - Since:
- 1.0
- See Also:
setVisible(boolean)
isEnabled
public boolean isEnabled()
Determines whether this component is enabled. An enabled component can respond to user input and generate events. Components are enabled initially by default. A component may be enabled or disabled by calling its setEnabled
method.
- Returns:
-
true
if the component is enabled,false
otherwise - Since:
- 1.0
- See Also:
setEnabled(boolean)
setEnabled
public void setEnabled(boolean b)
Enables or disables this component, depending on the value of the parameter b
. An enabled component can respond to user input and generate events. Components are enabled initially by default.
Note: Disabling a lightweight component does not prevent it from receiving MouseEvents.
Note: Disabling a heavyweight container prevents all components in this container from receiving any input events. But disabling a lightweight container affects only this container.
- Parameters:
-
b
- Iftrue
, this component is enabled; otherwise this component is disabled - Since:
- 1.1
- See Also:
-
isEnabled()
,isLightweight()
enable
@Deprecated public void enable()
setEnabled(boolean)
.enable
@Deprecated public void enable(boolean b)
setEnabled(boolean)
.Enables or disables this component.
- Parameters:
-
b
-true
to enable this component; otherwisefalse
disable
@Deprecated public void disable()
setEnabled(boolean)
.isDoubleBuffered
public boolean isDoubleBuffered()
Returns true if this component is painted to an offscreen image ("buffer") that's copied to the screen later. Component subclasses that support double buffering should override this method to return true if double buffering is enabled.
- Returns:
- false by default
enableInputMethods
public void enableInputMethods(boolean enable)
Enables or disables input method support for this component. If input method support is enabled and the component also processes key events, incoming events are offered to the current input method and will only be processed by the component or dispatched to its listeners if the input method does not consume them. By default, input method support is enabled.
- Parameters:
-
enable
- true to enable, false to disable - Since:
- 1.2
- See Also:
processKeyEvent(java.awt.event.KeyEvent)
setVisible
public void setVisible(boolean b)
Shows or hides this component depending on the value of parameter b
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
b
- iftrue
, shows this component; otherwise, hides this component - Since:
- 1.1
- See Also:
-
isVisible()
,invalidate()
show
@Deprecated public void show()
setVisible(boolean)
.show
@Deprecated public void show(boolean b)
setVisible(boolean)
.Makes this component visible or invisible.
- Parameters:
-
b
-true
to make this component visible; otherwisefalse
hide
@Deprecated public void hide()
setVisible(boolean)
.getForeground
public Color getForeground()
Gets the foreground color of this component.
- Returns:
- this component's foreground color; if this component does not have a foreground color, the foreground color of its parent is returned
- Since:
- 1.0
- See Also:
setForeground(java.awt.Color)
setForeground
public void setForeground(Color c)
Sets the foreground color of this component.
- Parameters:
-
c
- the color to become this component's foreground color; if this parameter isnull
then this component will inherit the foreground color of its parent - Since:
- 1.0
- See Also:
getForeground()
isForegroundSet
public boolean isForegroundSet()
Returns whether the foreground color has been explicitly set for this Component. If this method returns false
, this Component is inheriting its foreground color from an ancestor.
- Returns:
-
true
if the foreground color has been explicitly set for this Component;false
otherwise. - Since:
- 1.4
getBackground
public Color getBackground()
Gets the background color of this component.
- Returns:
- this component's background color; if this component does not have a background color, the background color of its parent is returned
- Since:
- 1.0
- See Also:
setBackground(java.awt.Color)
setBackground
public void setBackground(Color c)
Sets the background color of this component.
The background color affects each component differently and the parts of the component that are affected by the background color may differ between operating systems.
- Parameters:
-
c
- the color to become this component's color; if this parameter isnull
, then this component will inherit the background color of its parent - Since:
- 1.0
- See Also:
getBackground()
isBackgroundSet
public boolean isBackgroundSet()
Returns whether the background color has been explicitly set for this Component. If this method returns false
, this Component is inheriting its background color from an ancestor.
- Returns:
-
true
if the background color has been explicitly set for this Component;false
otherwise. - Since:
- 1.4
getFont
public Font getFont()
Gets the font of this component.
- Specified by:
-
getFont
in interfaceMenuContainer
- Returns:
- this component's font; if a font has not been set for this component, the font of its parent is returned
- Since:
- 1.0
- See Also:
setFont(java.awt.Font)
setFont
public void setFont(Font f)
Sets the font of this component.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
f
- the font to become this component's font; if this parameter isnull
then this component will inherit the font of its parent - Since:
- 1.0
- See Also:
-
getFont()
,invalidate()
isFontSet
public boolean isFontSet()
Returns whether the font has been explicitly set for this Component. If this method returns false
, this Component is inheriting its font from an ancestor.
- Returns:
-
true
if the font has been explicitly set for this Component;false
otherwise. - Since:
- 1.4
getLocale
public Locale getLocale()
Gets the locale of this component.
- Returns:
- this component's locale; if this component does not have a locale, the locale of its parent is returned
- Throws:
-
IllegalComponentStateException
- if theComponent
does not have its own locale and has not yet been added to a containment hierarchy such that the locale can be determined from the containing parent - Since:
- 1.1
- See Also:
setLocale(java.util.Locale)
setLocale
public void setLocale(Locale l)
Sets the locale of this component. This is a bound property.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
l
- the locale to become this component's locale - Since:
- 1.1
- See Also:
-
getLocale()
,invalidate()
getColorModel
public ColorModel getColorModel()
Gets the instance of ColorModel
used to display the component on the output device.
- Returns:
- the color model used by this component
- Since:
- 1.0
- See Also:
-
ColorModel
,ComponentPeer.getColorModel()
,Toolkit.getColorModel()
getLocation
public Point getLocation()
Gets the location of this component in the form of a point specifying the component's top-left corner. The location will be relative to the parent's coordinate space.
Due to the asynchronous nature of native event handling, this method can return outdated values (for instance, after several calls of setLocation()
in rapid succession). For this reason, the recommended method of obtaining a component's position is within java.awt.event.ComponentListener.componentMoved()
, which is called after the operating system has finished moving the component.
- Returns:
- an instance of
Point
representing the top-left corner of the component's bounds in the coordinate space of the component's parent - Since:
- 1.1
- See Also:
-
setLocation(int, int)
,getLocationOnScreen()
getLocationOnScreen
public Point getLocationOnScreen()
Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space.
- Returns:
- an instance of
Point
representing the top-left corner of the component's bounds in the coordinate space of the screen - Throws:
-
IllegalComponentStateException
- if the component is not showing on the screen - See Also:
-
setLocation(int, int)
,getLocation()
location
@Deprecated public Point location()
getLocation()
.Returns the location of this component's top left corner.
- Returns:
- the location of this component's top left corner
setLocation
public void setLocation(int x, int y)
Moves this component to a new location. The top-left corner of the new location is specified by the x
and y
parameters in the coordinate space of this component's parent.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
x
- the x-coordinate of the new location's top-left corner in the parent's coordinate space -
y
- the y-coordinate of the new location's top-left corner in the parent's coordinate space - Since:
- 1.1
- See Also:
-
getLocation()
,setBounds(int, int, int, int)
,invalidate()
move
@Deprecated public void move(int x, int y)
setLocation(int, int)
.Moves this component to a new location.
- Parameters:
-
x
- the x-coordinate of the new location's top-left corner in the parent's coordinate space -
y
- the y-coordinate of the new location's top-left corner in the parent's coordinate space
setLocation
public void setLocation(Point p)
Moves this component to a new location. The top-left corner of the new location is specified by point p
. Point p
is given in the parent's coordinate space.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
p
- the point defining the top-left corner of the new location, given in the coordinate space of this component's parent - Since:
- 1.1
- See Also:
-
getLocation()
,setBounds(int, int, int, int)
,invalidate()
getSize
public Dimension getSize()
Returns the size of this component in the form of a Dimension
object. The height
field of the Dimension
object contains this component's height, and the width
field of the Dimension
object contains this component's width.
- Returns:
- a
Dimension
object that indicates the size of this component - Since:
- 1.1
- See Also:
setSize(int, int)
size
@Deprecated public Dimension size()
getSize()
.Returns the size of this component in the form of a Dimension
object.
- Returns:
- the
Dimension
object that indicates the size of this component
setSize
public void setSize(int width, int height)
Resizes this component so that it has width width
and height height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
width
- the new width of this component in pixels -
height
- the new height of this component in pixels - Since:
- 1.1
- See Also:
-
getSize()
,setBounds(int, int, int, int)
,invalidate()
resize
@Deprecated public void resize(int width, int height)
setSize(int, int)
.Resizes this component.
- Parameters:
-
width
- the new width of the component -
height
- the new height of the component
setSize
public void setSize(Dimension d)
Resizes this component so that it has width d.width
and height d.height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
d
- the dimension specifying the new size of this component - Throws:
-
NullPointerException
- ifd
isnull
- Since:
- 1.1
- See Also:
-
setSize(int, int)
,setBounds(int, int, int, int)
,invalidate()
resize
@Deprecated public void resize(Dimension d)
setSize(Dimension)
.Resizes this component so that it has width d.width
and height d.height
.
- Parameters:
-
d
- the new size of this component
getBounds
public Rectangle getBounds()
Gets the bounds of this component in the form of a Rectangle
object. The bounds specify this component's width, height, and location relative to its parent.
- Returns:
- a rectangle indicating this component's bounds
- See Also:
-
setBounds(int, int, int, int)
,getLocation()
,getSize()
bounds
@Deprecated public Rectangle bounds()
getBounds()
.Returns the bounding rectangle of this component.
- Returns:
- the bounding rectangle for this component
setBounds
public void setBounds(int x, int y, int width, int height)
Moves and resizes this component. The new location of the top-left corner is specified by x
and y
, and the new size is specified by width
and height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
x
- the new x-coordinate of this component -
y
- the new y-coordinate of this component -
width
- the newwidth
of this component -
height
- the newheight
of this component - Since:
- 1.1
- See Also:
-
getBounds()
,setLocation(int, int)
,setLocation(Point)
,setSize(int, int)
,setSize(Dimension)
,invalidate()
reshape
@Deprecated public void reshape(int x, int y, int width, int height)
setBounds(int, int, int, int)
.Reshapes the bounding rectangle for this component.
- Parameters:
-
x
- the x coordinate of the upper left corner of the rectangle -
y
- the y coordinate of the upper left corner of the rectangle -
width
- the width of the rectangle -
height
- the height of the rectangle
setBounds
public void setBounds(Rectangle r)
Moves and resizes this component to conform to the new bounding rectangle r
. This component's new position is specified by r.x
and r.y
, and its new size is specified by r.width
and r.height
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
r
- the new bounding rectangle for this component - Throws:
-
NullPointerException
- ifr
isnull
- Since:
- 1.1
- See Also:
-
getBounds()
,setLocation(int, int)
,setLocation(Point)
,setSize(int, int)
,setSize(Dimension)
,invalidate()
getX
public int getX()
Returns the current x coordinate of the components origin. This method is preferable to writing component.getBounds().x
, or component.getLocation().x
because it doesn't cause any heap allocations.
- Returns:
- the current x coordinate of the components origin
- Since:
- 1.2
getY
public int getY()
Returns the current y coordinate of the components origin. This method is preferable to writing component.getBounds().y
, or component.getLocation().y
because it doesn't cause any heap allocations.
- Returns:
- the current y coordinate of the components origin
- Since:
- 1.2
getWidth
public int getWidth()
Returns the current width of this component. This method is preferable to writing component.getBounds().width
, or component.getSize().width
because it doesn't cause any heap allocations.
- Returns:
- the current width of this component
- Since:
- 1.2
getHeight
public int getHeight()
Returns the current height of this component. This method is preferable to writing component.getBounds().height
, or component.getSize().height
because it doesn't cause any heap allocations.
- Returns:
- the current height of this component
- Since:
- 1.2
getBounds
public Rectangle getBounds(Rectangle rv)
Stores the bounds of this component into "return value" rv and return rv. If rv is null
a new Rectangle
is allocated. This version of getBounds
is useful if the caller wants to avoid allocating a new Rectangle
object on the heap.
- Parameters:
-
rv
- the return value, modified to the components bounds - Returns:
- rv
getSize
public Dimension getSize(Dimension rv)
Stores the width/height of this component into "return value" rv and return rv. If rv is null
a new Dimension
object is allocated. This version of getSize
is useful if the caller wants to avoid allocating a new Dimension
object on the heap.
- Parameters:
-
rv
- the return value, modified to the components size - Returns:
- rv
getLocation
public Point getLocation(Point rv)
Stores the x,y origin of this component into "return value" rv and return rv. If rv is null
a new Point
is allocated. This version of getLocation
is useful if the caller wants to avoid allocating a new Point
object on the heap.
- Parameters:
-
rv
- the return value, modified to the components location - Returns:
- rv
isOpaque
public boolean isOpaque()
Returns true if this component is completely opaque, returns false by default.
An opaque component paints every pixel within its rectangular region. A non-opaque component paints only some of its pixels, allowing the pixels underneath it to "show through". A component that does not fully paint its pixels therefore provides a degree of transparency.
Subclasses that guarantee to always completely paint their contents should override this method and return true.
- Returns:
- true if this component is completely opaque
- Since:
- 1.2
- See Also:
isLightweight()
isLightweight
public boolean isLightweight()
A lightweight component doesn't have a native toolkit peer. Subclasses of Component
and Container
, other than the ones defined in this package like Button
or Scrollbar
, are lightweight. All of the Swing components are lightweights.
This method will always return false
if this component is not displayable because it is impossible to determine the weight of an undisplayable component.
- Returns:
- true if this component has a lightweight peer; false if it has a native peer or no peer
- Since:
- 1.2
- See Also:
isDisplayable()
setPreferredSize
public void setPreferredSize(Dimension preferredSize)
Sets the preferred size of this component to a constant value. Subsequent calls to getPreferredSize
will always return this value. Setting the preferred size to null
restores the default behavior.
- Parameters:
-
preferredSize
- The new preferred size, or null - Since:
- 1.5
- See Also:
-
getPreferredSize()
,isPreferredSizeSet()
isPreferredSizeSet
public boolean isPreferredSizeSet()
Returns true if the preferred size has been set to a non-null
value otherwise returns false.
- Returns:
- true if
setPreferredSize
has been invoked with a non-null value. - Since:
- 1.5
getPreferredSize
public Dimension getPreferredSize()
Gets the preferred size of this component.
- Returns:
- a dimension object indicating this component's preferred size
- See Also:
-
getMinimumSize()
,LayoutManager
preferredSize
@Deprecated public Dimension preferredSize()
getPreferredSize()
.Returns the component's preferred size.
- Returns:
- the component's preferred size
setMinimumSize
public void setMinimumSize(Dimension minimumSize)
Sets the minimum size of this component to a constant value. Subsequent calls to getMinimumSize
will always return this value. Setting the minimum size to null
restores the default behavior.
- Parameters:
-
minimumSize
- the new minimum size of this component - Since:
- 1.5
- See Also:
-
getMinimumSize()
,isMinimumSizeSet()
isMinimumSizeSet
public boolean isMinimumSizeSet()
Returns whether or not setMinimumSize
has been invoked with a non-null value.
- Returns:
- true if
setMinimumSize
has been invoked with a non-null value. - Since:
- 1.5
getMinimumSize
public Dimension getMinimumSize()
Gets the minimum size of this component.
- Returns:
- a dimension object indicating this component's minimum size
- See Also:
-
getPreferredSize()
,LayoutManager
minimumSize
@Deprecated public Dimension minimumSize()
getMinimumSize()
.Returns the minimum size of this component.
- Returns:
- the minimum size of this component
setMaximumSize
public void setMaximumSize(Dimension maximumSize)
Sets the maximum size of this component to a constant value. Subsequent calls to getMaximumSize
will always return this value. Setting the maximum size to null
restores the default behavior.
- Parameters:
-
maximumSize
- aDimension
containing the desired maximum allowable size - Since:
- 1.5
- See Also:
-
getMaximumSize()
,isMaximumSizeSet()
isMaximumSizeSet
public boolean isMaximumSizeSet()
Returns true if the maximum size has been set to a non-null
value otherwise returns false.
- Returns:
- true if
maximumSize
is non-null
, false otherwise - Since:
- 1.5
getMaximumSize
public Dimension getMaximumSize()
Gets the maximum size of this component.
- Returns:
- a dimension object indicating this component's maximum size
- See Also:
-
getMinimumSize()
,getPreferredSize()
,LayoutManager
getAlignmentX
public float getAlignmentX()
Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.
- Returns:
- the horizontal alignment of this component
getAlignmentY
public float getAlignmentY()
Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.
- Returns:
- the vertical alignment of this component
getBaseline
public int getBaseline(int width, int height)
Returns the baseline. The baseline is measured from the top of the component. This method is primarily meant for LayoutManager
s to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and that LayoutManager
s should not align this component on its baseline.
The default implementation returns -1. Subclasses that support baseline should override appropriately. If a value >= 0 is returned, then the component has a valid baseline for any size >= the minimum size and getBaselineResizeBehavior
can be used to determine how the baseline changes with size.
- Parameters:
-
width
- the width to get the baseline for -
height
- the height to get the baseline for - Returns:
- the baseline or < 0 indicating there is no reasonable baseline
- Throws:
-
IllegalArgumentException
- if width or height is < 0 - Since:
- 1.6
- See Also:
-
getBaselineResizeBehavior()
,FontMetrics
getBaselineResizeBehavior
public Component.BaselineResizeBehavior getBaselineResizeBehavior()
Returns an enum indicating how the baseline of the component changes as the size changes. This method is primarily meant for layout managers and GUI builders.
The default implementation returns BaselineResizeBehavior.OTHER
. Subclasses that have a baseline should override appropriately. Subclasses should never return null
; if the baseline can not be calculated return BaselineResizeBehavior.OTHER
. Callers should first ask for the baseline using getBaseline
and if a value >= 0 is returned use this method. It is acceptable for this method to return a value other than BaselineResizeBehavior.OTHER
even if getBaseline
returns a value less than 0.
- Returns:
- an enum indicating how the baseline changes as the component size changes
- Since:
- 1.6
- See Also:
getBaseline(int, int)
doLayout
public void doLayout()
Prompts the layout manager to lay out this component. This is usually called when the component (more specifically, container) is validated.
- See Also:
-
validate()
,LayoutManager
layout
@Deprecated public void layout()
doLayout()
.validate
public void validate()
Validates this component.
The meaning of the term validating is defined by the ancestors of this class. See Container.validate()
for more details.
- Since:
- 1.0
- See Also:
-
invalidate()
,doLayout()
,LayoutManager
,Container.validate()
invalidate
public void invalidate()
Invalidates this component and its ancestors.
By default, all the ancestors of the component up to the top-most container of the hierarchy are marked invalid. If the
java.awt.smartInvalidate
system property is set to true
, invalidation stops on the nearest validate root of this component. Marking a container invalid indicates that the container needs to be laid out.
This method is called automatically when any layout-related information changes (e.g. setting the bounds of the component, or adding the component to a container).
This method might be called often, so it should work fast.
- Since:
- 1.0
- See Also:
-
validate()
,doLayout()
,LayoutManager
,Container.isValidateRoot()
revalidate
public void revalidate()
Revalidates the component hierarchy up to the nearest validate root.
This method first invalidates the component hierarchy starting from this component up to the nearest validate root. Afterwards, the component hierarchy is validated starting from the nearest validate root.
This is a convenience method supposed to help application developers avoid looking for validate roots manually. Basically, it's equivalent to first calling the invalidate()
method on this component, and then calling the validate()
method on the nearest validate root.
- Since:
- 1.7
- See Also:
Container.isValidateRoot()
getGraphics
public Graphics getGraphics()
Creates a graphics context for this component. This method will return null
if this component is currently not displayable.
- Returns:
- a graphics context for this component, or
null
if it has none - Since:
- 1.0
- See Also:
paint(java.awt.Graphics)
getFontMetrics
public FontMetrics getFontMetrics(Font font)
Gets the font metrics for the specified font. Warning: Since Font metrics are affected by the FontRenderContext
and this method does not provide one, it can return only metrics for the default render context which may not match that used when rendering on the Component if Graphics2D
functionality is being used. Instead metrics can be obtained at rendering time by calling Graphics.getFontMetrics()
or text measurement APIs on the Font
class.
- Parameters:
-
font
- the font for which font metrics is to be obtained - Returns:
- the font metrics for
font
- Since:
- 1.0
- See Also:
-
getFont()
,ComponentPeer.getFontMetrics(Font)
,Toolkit.getFontMetrics(Font)
setCursor
public void setCursor(Cursor cursor)
Sets the cursor image to the specified cursor. This cursor image is displayed when the contains
method for this component returns true for the current cursor location, and this Component is visible, displayable, and enabled. Setting the cursor of a Container
causes that cursor to be displayed within all of the container's subcomponents, except for those that have a non-null
cursor.
The method may have no visual effect if the Java platform implementation and/or the native system do not support changing the mouse cursor shape.
- Parameters:
-
cursor
- One of the constants defined by theCursor
class; if this parameter isnull
then this component will inherit the cursor of its parent - Since:
- 1.1
- See Also:
-
isEnabled()
,isShowing()
,getCursor()
,contains(int, int)
,Toolkit.createCustomCursor(java.awt.Image, java.awt.Point, java.lang.String)
,Cursor
getCursor
public Cursor getCursor()
Gets the cursor set in the component. If the component does not have a cursor set, the cursor of its parent is returned. If no cursor is set in the entire hierarchy, Cursor.DEFAULT_CURSOR
is returned.
- Returns:
- the cursor for this component
- Since:
- 1.1
- See Also:
setCursor(java.awt.Cursor)
isCursorSet
public boolean isCursorSet()
Returns whether the cursor has been explicitly set for this Component. If this method returns false
, this Component is inheriting its cursor from an ancestor.
- Returns:
-
true
if the cursor has been explicitly set for this Component;false
otherwise. - Since:
- 1.4
paint
public void paint(Graphics g)
Paints this component.
This method is called when the contents of the component should be painted; such as when the component is first being shown or is damaged and in need of repair. The clip rectangle in the Graphics
parameter is set to the area which needs to be painted. Subclasses of Component
that override this method need not call super.paint(g)
.
For performance reasons, Component
s with zero width or height aren't considered to need painting when they are first shown, and also aren't considered to need repair.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Parameters:
-
g
- the graphics context to use for painting - Since:
- 1.0
- See Also:
update(java.awt.Graphics)
update
public void update(Graphics g)
Updates this component.
If this component is not a lightweight component, the AWT calls the update
method in response to a call to repaint
. You can assume that the background is not cleared.
The update
method of Component
calls this component's paint
method to redraw this component. This method is commonly overridden by subclasses which need to do additional work in response to a call to repaint
. Subclasses of Component that override this method should either call super.update(g)
, or call paint(g)
directly from their update
method.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Parameters:
-
g
- the specified context to use for updating - Since:
- 1.0
- See Also:
-
paint(java.awt.Graphics)
,repaint()
paintAll
public void paintAll(Graphics g)
Paints this component and all of its subcomponents.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
- Parameters:
-
g
- the graphics context to use for painting - Since:
- 1.0
- See Also:
paint(java.awt.Graphics)
repaint
public void repaint()
Repaints this component.
If this component is a lightweight component, this method causes a call to this component's paint
method as soon as possible. Otherwise, this method causes a call to this component's update
method as soon as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Since:
- 1.0
- See Also:
update(Graphics)
repaint
public void repaint(long tm)
Repaints the component. If this component is a lightweight component, this results in a call to paint
within tm
milliseconds.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Parameters:
-
tm
- maximum time in milliseconds before update - Since:
- 1.0
- See Also:
-
paint(java.awt.Graphics)
,update(Graphics)
repaint
public void repaint(int x, int y, int width, int height)
Repaints the specified rectangle of this component.
If this component is a lightweight component, this method causes a call to this component's paint
method as soon as possible. Otherwise, this method causes a call to this component's update
method as soon as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Parameters:
-
x
- the x coordinate -
y
- the y coordinate -
width
- the width -
height
- the height - Since:
- 1.0
- See Also:
update(Graphics)
repaint
public void repaint(long tm, int x, int y, int width, int height)
Repaints the specified rectangle of this component within tm
milliseconds.
If this component is a lightweight component, this method causes a call to this component's paint
method. Otherwise, this method causes a call to this component's update
method.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
- Parameters:
-
tm
- maximum time in milliseconds before update -
x
- the x coordinate -
y
- the y coordinate -
width
- the width -
height
- the height - Since:
- 1.0
- See Also:
update(Graphics)
public void print(Graphics g)
Prints this component. Applications should override this method for components that must do special processing before being printed or should be printed differently than they are painted.
The default implementation of this method calls the paint
method.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
- Parameters:
-
g
- the graphics context to use for printing - Since:
- 1.0
- See Also:
paint(Graphics)
printAll
public void printAll(Graphics g)
Prints this component and all of its subcomponents.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
- Parameters:
-
g
- the graphics context to use for printing - Since:
- 1.0
- See Also:
print(Graphics)
imageUpdate
public boolean imageUpdate(Image img, int infoflags, int x, int y, int w, int h)
Repaints the component when the image has changed. This imageUpdate
method of an ImageObserver
is called when more information about an image which had been previously requested using an asynchronous routine such as the drawImage
method of Graphics
becomes available. See the definition of imageUpdate
for more information on this method and its arguments.
The imageUpdate
method of Component
incrementally draws an image on the component as more of the bits of the image are available.
If the system property awt.image.incrementaldraw
is missing or has the value true
, the image is incrementally drawn. If the system property has any other value, then the image is not drawn until it has been completely loaded.
Also, if incremental drawing is in effect, the value of the system property awt.image.redrawrate
is interpreted as an integer to give the maximum redraw rate, in milliseconds. If the system property is missing or cannot be interpreted as an integer, the redraw rate is once every 100ms.
The interpretation of the x
, y
, width
, and height
arguments depends on the value of the infoflags
argument.
- Specified by:
-
imageUpdate
in interfaceImageObserver
- Parameters:
-
img
- the image being observed -
infoflags
- seeimageUpdate
for more information -
x
- the x coordinate -
y
- the y coordinate -
w
- the width -
h
- the height - Returns:
-
false
if the infoflags indicate that the image is completely loaded;true
otherwise. - Since:
- 1.0
- See Also:
-
ImageObserver
,Graphics.drawImage(Image, int, int, Color, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, int, int, Color, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, int, int, java.awt.image.ImageObserver)
,ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)
createImage
public Image createImage(ImageProducer producer)
Creates an image from the specified image producer.
- Parameters:
-
producer
- the image producer - Returns:
- the image produced
- Since:
- 1.0
createImage
public Image createImage(int width, int height)
Creates an off-screen drawable image to be used for double buffering.
- Parameters:
-
width
- the specified width -
height
- the specified height - Returns:
- an off-screen drawable image, which can be used for double buffering. The
null
value if the component is not displayable orGraphicsEnvironment.isHeadless()
returnstrue
. - Since:
- 1.0
- See Also:
-
isDisplayable()
,GraphicsEnvironment.isHeadless()
createVolatileImage
public VolatileImage createVolatileImage(int width, int height)
Creates a volatile off-screen drawable image to be used for double buffering.
- Parameters:
-
width
- the specified width -
height
- the specified height - Returns:
- an off-screen drawable image, which can be used for double buffering. The
null
value if the component is not displayable orGraphicsEnvironment.isHeadless()
returnstrue
. - Since:
- 1.4
- See Also:
-
VolatileImage
,isDisplayable()
,GraphicsEnvironment.isHeadless()
createVolatileImage
public VolatileImage createVolatileImage(int width, int height, ImageCapabilities caps) throws AWTException
Creates a volatile off-screen drawable image, with the given capabilities. The contents of this image may be lost at any time due to operating system issues, so the image must be managed via the VolatileImage
interface.
- Parameters:
-
width
- the specified width -
height
- the specified height -
caps
- the image capabilities - Returns:
- a VolatileImage object, which can be used to manage surface contents loss and capabilities. The
null
value if the component is not displayable orGraphicsEnvironment.isHeadless()
returnstrue
. - Throws:
-
AWTException
- if an image with the specified capabilities cannot be created - Since:
- 1.4
- See Also:
VolatileImage
prepareImage
public boolean prepareImage(Image image, ImageObserver observer)
Prepares an image for rendering on this component. The image data is downloaded asynchronously in another thread and the appropriate screen representation of the image is generated.
- Parameters:
-
image
- theImage
for which to prepare a screen representation -
observer
- theImageObserver
object to be notified as the image is being prepared - Returns:
-
true
if the image has already been fully prepared;false
otherwise - Since:
- 1.0
prepareImage
public boolean prepareImage(Image image, int width, int height, ImageObserver observer)
Prepares an image for rendering on this component at the specified width and height.
The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.
- Parameters:
-
image
- the instance ofImage
for which to prepare a screen representation -
width
- the width of the desired screen representation -
height
- the height of the desired screen representation -
observer
- theImageObserver
object to be notified as the image is being prepared - Returns:
-
true
if the image has already been fully prepared;false
otherwise - Since:
- 1.0
- See Also:
ImageObserver
checkImage
public int checkImage(Image image, ImageObserver observer)
Returns the status of the construction of a screen representation of the specified image.
This method does not cause the image to begin loading. An application must use the prepareImage
method to force the loading of an image.
Information on the flags returned by this method can be found with the discussion of the ImageObserver
interface.
- Parameters:
-
image
- theImage
object whose status is being checked -
observer
- theImageObserver
object to be notified as the image is being prepared - Returns:
- the bitwise inclusive OR of
ImageObserver
flags indicating what information about the image is currently available - Since:
- 1.0
- See Also:
-
prepareImage(Image, int, int, java.awt.image.ImageObserver)
,Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,ImageObserver
checkImage
public int checkImage(Image image, int width, int height, ImageObserver observer)
Returns the status of the construction of a screen representation of the specified image.
This method does not cause the image to begin loading. An application must use the prepareImage
method to force the loading of an image.
The checkImage
method of Component
calls its peer's checkImage
method to calculate the flags. If this component does not yet have a peer, the component's toolkit's checkImage
method is called instead.
Information on the flags returned by this method can be found with the discussion of the ImageObserver
interface.
- Parameters:
-
image
- theImage
object whose status is being checked -
width
- the width of the scaled version whose status is to be checked -
height
- the height of the scaled version whose status is to be checked -
observer
- theImageObserver
object to be notified as the image is being prepared - Returns:
- the bitwise inclusive OR of
ImageObserver
flags indicating what information about the image is currently available - Since:
- 1.0
- See Also:
-
prepareImage(Image, int, int, java.awt.image.ImageObserver)
,Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,ImageObserver
setIgnoreRepaint
public void setIgnoreRepaint(boolean ignoreRepaint)
Sets whether or not paint messages received from the operating system should be ignored. This does not affect paint events generated in software by the AWT, unless they are an immediate response to an OS-level paint message.
This is useful, for example, if running under full-screen mode and better performance is desired, or if page-flipping is used as the buffer strategy.
- Parameters:
-
ignoreRepaint
-true
if the paint messages from the OS should be ignored; otherwisefalse
- Since:
- 1.4
- See Also:
-
getIgnoreRepaint()
,Canvas.createBufferStrategy(int)
,Window.createBufferStrategy(int)
,BufferStrategy
,GraphicsDevice.setFullScreenWindow(java.awt.Window)
getIgnoreRepaint
public boolean getIgnoreRepaint()
- Returns:
- whether or not paint messages received from the operating system should be ignored.
- Since:
- 1.4
- See Also:
setIgnoreRepaint(boolean)
contains
public boolean contains(int x, int y)
Checks whether this component "contains" the specified point, where x
and y
are defined to be relative to the coordinate system of this component.
- Parameters:
-
x
- the x coordinate of the point -
y
- the y coordinate of the point - Returns:
-
true
if the point is within the component; otherwisefalse
- Since:
- 1.1
- See Also:
getComponentAt(int, int)
inside
@Deprecated public boolean inside(int x, int y)
Checks whether the point is inside of this component.
- Parameters:
-
x
- the x coordinate of the point -
y
- the y coordinate of the point - Returns:
-
true
if the point is within the component; otherwisefalse
contains
public boolean contains(Point p)
Checks whether this component "contains" the specified point, where the point's x and y coordinates are defined to be relative to the coordinate system of this component.
- Parameters:
-
p
- the point - Returns:
-
true
if the point is within the component; otherwisefalse
- Throws:
-
NullPointerException
- ifp
isnull
- Since:
- 1.1
- See Also:
getComponentAt(Point)
getComponentAt
public Component getComponentAt(int x, int y)
Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component. This method only looks one level deep. If the point (x, y) is inside a subcomponent that itself has subcomponents, it does not go looking down the subcomponent tree.
The locate
method of Component
simply returns the component itself if the (x, y) coordinate location is inside its bounding box, and null
otherwise.
- Parameters:
-
x
- the x coordinate -
y
- the y coordinate - Returns:
- the component or subcomponent that contains the (x, y) location;
null
if the location is outside this component - Since:
- 1.0
- See Also:
contains(int, int)
locate
@Deprecated public Component locate(int x, int y)
Returns the component occupying the position specified (this component, or immediate child component, or null if neither of the first two occupies the location).
- Parameters:
-
x
- the x coordinate to search for components at -
y
- the y coordinate to search for components at - Returns:
- the component at the specified location or
null
getComponentAt
public Component getComponentAt(Point p)
Returns the component or subcomponent that contains the specified point.
- Parameters:
-
p
- the point - Returns:
- the component at the specified location or
null
- Since:
- 1.1
- See Also:
contains(int, int)
deliverEvent
@Deprecated public void deliverEvent(Event e)
dispatchEvent(AWTEvent e)
.- Parameters:
-
e
- the event to deliver
dispatchEvent
public final void dispatchEvent(AWTEvent e)
Dispatches an event to this component or one of its sub components. Calls processEvent
before returning for 1.1-style events which have been enabled for the Component
.
- Parameters:
-
e
- the event
postEvent
@Deprecated public boolean postEvent(Event e)
Description copied from interface: MenuContainer
Posts an event to the listeners.
- Specified by:
-
postEvent
in interfaceMenuContainer
- Parameters:
-
e
- the event to dispatch - Returns:
- the results of posting the event
addComponentListener
public void addComponentListener(ComponentListener l)
Adds the specified component listener to receive component events from this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the component listener - Since:
- 1.1
- See Also:
-
ComponentEvent
,ComponentListener
,removeComponentListener(java.awt.event.ComponentListener)
,getComponentListeners()
removeComponentListener
public void removeComponentListener(ComponentListener l)
Removes the specified component listener so that it no longer receives component events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the component listener - Since:
- 1.1
- See Also:
-
ComponentEvent
,ComponentListener
,addComponentListener(java.awt.event.ComponentListener)
,getComponentListeners()
getComponentListeners
public ComponentListener[] getComponentListeners()
Returns an array of all the component listeners registered on this component.
- Returns:
- all
ComponentListener
s of this component or an empty array if no component listeners are currently registered - Since:
- 1.4
- See Also:
-
addComponentListener(java.awt.event.ComponentListener)
,removeComponentListener(java.awt.event.ComponentListener)
addFocusListener
public void addFocusListener(FocusListener l)
Adds the specified focus listener to receive focus events from this component when this component gains input focus. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the focus listener - Since:
- 1.1
- See Also:
-
FocusEvent
,FocusListener
,removeFocusListener(java.awt.event.FocusListener)
,getFocusListeners()
removeFocusListener
public void removeFocusListener(FocusListener l)
Removes the specified focus listener so that it no longer receives focus events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the focus listener - Since:
- 1.1
- See Also:
-
FocusEvent
,FocusListener
,addFocusListener(java.awt.event.FocusListener)
,getFocusListeners()
getFocusListeners
public FocusListener[] getFocusListeners()
Returns an array of all the focus listeners registered on this component.
- Returns:
- all of this component's
FocusListener
s or an empty array if no component listeners are currently registered - Since:
- 1.4
- See Also:
-
addFocusListener(java.awt.event.FocusListener)
,removeFocusListener(java.awt.event.FocusListener)
addHierarchyListener
public void addHierarchyListener(HierarchyListener l)
Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the hierarchy listener - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyListener
,removeHierarchyListener(java.awt.event.HierarchyListener)
,getHierarchyListeners()
removeHierarchyListener
public void removeHierarchyListener(HierarchyListener l)
Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the hierarchy listener - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyListener
,addHierarchyListener(java.awt.event.HierarchyListener)
,getHierarchyListeners()
getHierarchyListeners
public HierarchyListener[] getHierarchyListeners()
Returns an array of all the hierarchy listeners registered on this component.
- Returns:
- all of this component's
HierarchyListener
s or an empty array if no hierarchy listeners are currently registered - Since:
- 1.4
- See Also:
-
addHierarchyListener(java.awt.event.HierarchyListener)
,removeHierarchyListener(java.awt.event.HierarchyListener)
addHierarchyBoundsListener
public void addHierarchyBoundsListener(HierarchyBoundsListener l)
Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the hierarchy bounds listener - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyBoundsListener
,removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,getHierarchyBoundsListeners()
removeHierarchyBoundsListener
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the hierarchy bounds listener - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyBoundsListener
,addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,getHierarchyBoundsListeners()
getHierarchyBoundsListeners
public HierarchyBoundsListener[] getHierarchyBoundsListeners()
Returns an array of all the hierarchy bounds listeners registered on this component.
- Returns:
- all of this component's
HierarchyBoundsListener
s or an empty array if no hierarchy bounds listeners are currently registered - Since:
- 1.4
- See Also:
-
addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
addKeyListener
public void addKeyListener(KeyListener l)
Adds the specified key listener to receive key events from this component. If l is null, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the key listener. - Since:
- 1.1
- See Also:
-
KeyEvent
,KeyListener
,removeKeyListener(java.awt.event.KeyListener)
,getKeyListeners()
removeKeyListener
public void removeKeyListener(KeyListener l)
Removes the specified key listener so that it no longer receives key events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the key listener - Since:
- 1.1
- See Also:
-
KeyEvent
,KeyListener
,addKeyListener(java.awt.event.KeyListener)
,getKeyListeners()
getKeyListeners
public KeyListener[] getKeyListeners()
Returns an array of all the key listeners registered on this component.
- Returns:
- all of this component's
KeyListener
s or an empty array if no key listeners are currently registered - Since:
- 1.4
- See Also:
-
addKeyListener(java.awt.event.KeyListener)
,removeKeyListener(java.awt.event.KeyListener)
addMouseListener
public void addMouseListener(MouseListener l)
Adds the specified mouse listener to receive mouse events from this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse listener - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseListener
,removeMouseListener(java.awt.event.MouseListener)
,getMouseListeners()
removeMouseListener
public void removeMouseListener(MouseListener l)
Removes the specified mouse listener so that it no longer receives mouse events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse listener - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseListener
,addMouseListener(java.awt.event.MouseListener)
,getMouseListeners()
getMouseListeners
public MouseListener[] getMouseListeners()
Returns an array of all the mouse listeners registered on this component.
- Returns:
- all of this component's
MouseListener
s or an empty array if no mouse listeners are currently registered - Since:
- 1.4
- See Also:
-
addMouseListener(java.awt.event.MouseListener)
,removeMouseListener(java.awt.event.MouseListener)
addMouseMotionListener
public void addMouseMotionListener(MouseMotionListener l)
Adds the specified mouse motion listener to receive mouse motion events from this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse motion listener - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseMotionListener
,removeMouseMotionListener(java.awt.event.MouseMotionListener)
,getMouseMotionListeners()
removeMouseMotionListener
public void removeMouseMotionListener(MouseMotionListener l)
Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse motion listener - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseMotionListener
,addMouseMotionListener(java.awt.event.MouseMotionListener)
,getMouseMotionListeners()
getMouseMotionListeners
public MouseMotionListener[] getMouseMotionListeners()
Returns an array of all the mouse motion listeners registered on this component.
- Returns:
- all of this component's
MouseMotionListener
s or an empty array if no mouse motion listeners are currently registered - Since:
- 1.4
- See Also:
-
addMouseMotionListener(java.awt.event.MouseMotionListener)
,removeMouseMotionListener(java.awt.event.MouseMotionListener)
addMouseWheelListener
public void addMouseWheelListener(MouseWheelListener l)
Adds the specified mouse wheel listener to receive mouse wheel events from this component. Containers also receive mouse wheel events from sub-components.
For information on how mouse wheel events are dispatched, see the class description for MouseWheelEvent
.
If l is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse wheel listener - Since:
- 1.4
- See Also:
-
MouseWheelEvent
,MouseWheelListener
,removeMouseWheelListener(java.awt.event.MouseWheelListener)
,getMouseWheelListeners()
removeMouseWheelListener
public void removeMouseWheelListener(MouseWheelListener l)
Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If l is null, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the mouse wheel listener. - Since:
- 1.4
- See Also:
-
MouseWheelEvent
,MouseWheelListener
,addMouseWheelListener(java.awt.event.MouseWheelListener)
,getMouseWheelListeners()
getMouseWheelListeners
public MouseWheelListener[] getMouseWheelListeners()
Returns an array of all the mouse wheel listeners registered on this component.
- Returns:
- all of this component's
MouseWheelListener
s or an empty array if no mouse wheel listeners are currently registered - Since:
- 1.4
- See Also:
-
addMouseWheelListener(java.awt.event.MouseWheelListener)
,removeMouseWheelListener(java.awt.event.MouseWheelListener)
addInputMethodListener
public void addInputMethodListener(InputMethodListener l)
Adds the specified input method listener to receive input method events from this component. A component will only receive input method events from input methods if it also overrides getInputMethodRequests
to return an InputMethodRequests
instance. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the input method listener - Since:
- 1.2
- See Also:
-
InputMethodEvent
,InputMethodListener
,removeInputMethodListener(java.awt.event.InputMethodListener)
,getInputMethodListeners()
,getInputMethodRequests()
removeInputMethodListener
public void removeInputMethodListener(InputMethodListener l)
Removes the specified input method listener so that it no longer receives input method events from this component. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this component. If listener l
is null
, no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
-
l
- the input method listener - Since:
- 1.2
- See Also:
-
InputMethodEvent
,InputMethodListener
,addInputMethodListener(java.awt.event.InputMethodListener)
,getInputMethodListeners()
getInputMethodListeners
public InputMethodListener[] getInputMethodListeners()
Returns an array of all the input method listeners registered on this component.
- Returns:
- all of this component's
InputMethodListener
s or an empty array if no input method listeners are currently registered - Since:
- 1.4
- See Also:
-
addInputMethodListener(java.awt.event.InputMethodListener)
,removeInputMethodListener(java.awt.event.InputMethodListener)
getListeners
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListener
s upon this Component
. FooListener
s are registered using the addFooListener
method.
You can specify the listenerType
argument with a class literal, such as FooListener.class
. For example, you can query a Component c
for its mouse listeners with the following code:
MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class));If no such listeners exist, this method returns an empty array.
- Type Parameters:
-
T
- the type of the listeners - Parameters:
-
listenerType
- the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
- Returns:
- an array of all objects registered as
FooListener
s on this component, or an empty array if no such listeners have been added - Throws:
-
ClassCastException
- iflistenerType
doesn't specify a class or interface that implementsjava.util.EventListener
-
NullPointerException
- iflistenerType
isnull
- Since:
- 1.3
- See Also:
-
getComponentListeners()
,getFocusListeners()
,getHierarchyListeners()
,getHierarchyBoundsListeners()
,getKeyListeners()
,getMouseListeners()
,getMouseMotionListeners()
,getMouseWheelListeners()
,getInputMethodListeners()
,getPropertyChangeListeners()
getInputMethodRequests
public InputMethodRequests getInputMethodRequests()
Gets the input method request handler which supports requests from input methods for this component. A component that supports on-the-spot text input must override this method to return an InputMethodRequests
instance. At the same time, it also has to handle input method events.
- Returns:
- the input method request handler for this component,
null
by default - Since:
- 1.2
- See Also:
addInputMethodListener(java.awt.event.InputMethodListener)
getInputContext
public InputContext getInputContext()
Gets the input context used by this component for handling the communication with input methods when text is entered in this component. By default, the input context used for the parent component is returned. Components may override this to return a private input context.
- Returns:
- the input context used by this component;
null
if no context can be determined - Since:
- 1.2
enableEvents
protected final void enableEvents(long eventsToEnable)
Enables the events defined by the specified event mask parameter to be delivered to this component.
Event types are automatically enabled when a listener for that event type is added to the component.
This method only needs to be invoked by subclasses of Component
which desire to have the specified event types delivered to processEvent
regardless of whether or not a listener is registered.
- Parameters:
-
eventsToEnable
- the event mask defining the event types - Since:
- 1.1
- See Also:
-
processEvent(java.awt.AWTEvent)
,disableEvents(long)
,AWTEvent
disableEvents
protected final void disableEvents(long eventsToDisable)
Disables the events defined by the specified event mask parameter from being delivered to this component.
- Parameters:
-
eventsToDisable
- the event mask defining the event types - Since:
- 1.1
- See Also:
enableEvents(long)
coalesceEvents
protected AWTEvent coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)
Potentially coalesce an event being posted with an existing event. This method is called by EventQueue.postEvent
if an event with the same ID as the event to be posted is found in the queue (both events must have this component as their source). This method either returns a coalesced event which replaces the existing event (and the new event is then discarded), or null
to indicate that no combining should be done (add the second event to the end of the queue). Either event parameter may be modified and returned, as the other one is discarded unless null
is returned.
This implementation of coalesceEvents
coalesces two event types: mouse move (and drag) events, and paint (and update) events. For mouse move events the last event is always returned, causing intermediate moves to be discarded. For paint events, the new event is coalesced into a complex RepaintArea
in the peer. The new AWTEvent
is always returned.
- Parameters:
-
existingEvent
- the event already on theEventQueue
-
newEvent
- the event being posted to theEventQueue
- Returns:
- a coalesced event, or
null
indicating that no coalescing was done
processEvent
protected void processEvent(AWTEvent e)
Processes events occurring on this component. By default this method calls the appropriate process<event type>Event
method for the given class of event.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the event - Since:
- 1.1
- See Also:
-
processComponentEvent(java.awt.event.ComponentEvent)
,processFocusEvent(java.awt.event.FocusEvent)
,processKeyEvent(java.awt.event.KeyEvent)
,processMouseEvent(java.awt.event.MouseEvent)
,processMouseMotionEvent(java.awt.event.MouseEvent)
,processInputMethodEvent(java.awt.event.InputMethodEvent)
,processHierarchyEvent(java.awt.event.HierarchyEvent)
,processMouseWheelEvent(java.awt.event.MouseWheelEvent)
processComponentEvent
protected void processComponentEvent(ComponentEvent e)
Processes component events occurring on this component by dispatching them to any registered ComponentListener
objects.
This method is not called unless component events are enabled for this component. Component events are enabled when one of the following occurs:
- A
ComponentListener
object is registered viaaddComponentListener
. - Component events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the component event - Since:
- 1.1
- See Also:
-
ComponentEvent
,ComponentListener
,addComponentListener(java.awt.event.ComponentListener)
,enableEvents(long)
processFocusEvent
protected void processFocusEvent(FocusEvent e)
Processes focus events occurring on this component by dispatching them to any registered FocusListener
objects.
This method is not called unless focus events are enabled for this component. Focus events are enabled when one of the following occurs:
- A
FocusListener
object is registered viaaddFocusListener
. - Focus events are enabled via
enableEvents
.
If focus events are enabled for a Component
, the current KeyboardFocusManager
determines whether or not a focus event should be dispatched to registered FocusListener
objects. If the events are to be dispatched, the KeyboardFocusManager
calls the Component
's dispatchEvent
method, which results in a call to the Component
's processFocusEvent
method.
If focus events are enabled for a Component
, calling the Component
's dispatchEvent
method with a FocusEvent
as the argument will result in a call to the Component
's processFocusEvent
method regardless of the current KeyboardFocusManager
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the focus event - Since:
- 1.1
- See Also:
-
FocusEvent
,FocusListener
,KeyboardFocusManager
,addFocusListener(java.awt.event.FocusListener)
,enableEvents(long)
,dispatchEvent(java.awt.AWTEvent)
processKeyEvent
protected void processKeyEvent(KeyEvent e)
Processes key events occurring on this component by dispatching them to any registered KeyListener
objects.
This method is not called unless key events are enabled for this component. Key events are enabled when one of the following occurs:
- A
KeyListener
object is registered viaaddKeyListener
. - Key events are enabled via
enableEvents
.
If key events are enabled for a Component
, the current KeyboardFocusManager
determines whether or not a key event should be dispatched to registered KeyListener
objects. The DefaultKeyboardFocusManager
will not dispatch key events to a Component
that is not the focus owner or is not showing.
As of J2SE 1.4, KeyEvent
s are redirected to the focus owner. Please see the Focus Specification for further information.
Calling a Component
's dispatchEvent
method with a KeyEvent
as the argument will result in a call to the Component
's processKeyEvent
method regardless of the current KeyboardFocusManager
as long as the component is showing, focused, and enabled, and key events are enabled on it.
If the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the key event - Since:
- 1.1
- See Also:
-
KeyEvent
,KeyListener
,KeyboardFocusManager
,DefaultKeyboardFocusManager
,processEvent(java.awt.AWTEvent)
,dispatchEvent(java.awt.AWTEvent)
,addKeyListener(java.awt.event.KeyListener)
,enableEvents(long)
,isShowing()
processMouseEvent
protected void processMouseEvent(MouseEvent e)
Processes mouse events occurring on this component by dispatching them to any registered MouseListener
objects.
This method is not called unless mouse events are enabled for this component. Mouse events are enabled when one of the following occurs:
- A
MouseListener
object is registered viaaddMouseListener
. - Mouse events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the mouse event - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseListener
,addMouseListener(java.awt.event.MouseListener)
,enableEvents(long)
processMouseMotionEvent
protected void processMouseMotionEvent(MouseEvent e)
Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener
objects.
This method is not called unless mouse motion events are enabled for this component. Mouse motion events are enabled when one of the following occurs:
- A
MouseMotionListener
object is registered viaaddMouseMotionListener
. - Mouse motion events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the mouse motion event - Since:
- 1.1
- See Also:
-
MouseEvent
,MouseMotionListener
,addMouseMotionListener(java.awt.event.MouseMotionListener)
,enableEvents(long)
processMouseWheelEvent
protected void processMouseWheelEvent(MouseWheelEvent e)
Processes mouse wheel events occurring on this component by dispatching them to any registered MouseWheelListener
objects.
This method is not called unless mouse wheel events are enabled for this component. Mouse wheel events are enabled when one of the following occurs:
- A
MouseWheelListener
object is registered viaaddMouseWheelListener
. - Mouse wheel events are enabled via
enableEvents
.
For information on how mouse wheel events are dispatched, see the class description for MouseWheelEvent
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the mouse wheel event - Since:
- 1.4
- See Also:
-
MouseWheelEvent
,MouseWheelListener
,addMouseWheelListener(java.awt.event.MouseWheelListener)
,enableEvents(long)
processInputMethodEvent
protected void processInputMethodEvent(InputMethodEvent e)
Processes input method events occurring on this component by dispatching them to any registered InputMethodListener
objects.
This method is not called unless input method events are enabled for this component. Input method events are enabled when one of the following occurs:
- An
InputMethodListener
object is registered viaaddInputMethodListener
. - Input method events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the input method event - Since:
- 1.2
- See Also:
-
InputMethodEvent
,InputMethodListener
,addInputMethodListener(java.awt.event.InputMethodListener)
,enableEvents(long)
processHierarchyEvent
protected void processHierarchyEvent(HierarchyEvent e)
Processes hierarchy events occurring on this component by dispatching them to any registered HierarchyListener
objects.
This method is not called unless hierarchy events are enabled for this component. Hierarchy events are enabled when one of the following occurs:
- An
HierarchyListener
object is registered viaaddHierarchyListener
. - Hierarchy events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the hierarchy event - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyListener
,addHierarchyListener(java.awt.event.HierarchyListener)
,enableEvents(long)
processHierarchyBoundsEvent
protected void processHierarchyBoundsEvent(HierarchyEvent e)
Processes hierarchy bounds events occurring on this component by dispatching them to any registered HierarchyBoundsListener
objects.
This method is not called unless hierarchy bounds events are enabled for this component. Hierarchy bounds events are enabled when one of the following occurs:
- An
HierarchyBoundsListener
object is registered viaaddHierarchyBoundsListener
. - Hierarchy bounds events are enabled via
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Parameters:
-
e
- the hierarchy event - Since:
- 1.3
- See Also:
-
HierarchyEvent
,HierarchyBoundsListener
,addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,enableEvents(long)
handleEvent
@Deprecated public boolean handleEvent(Event evt)
- Parameters:
-
evt
- the event to handle - Returns:
-
true
if the event was handled,false
otherwise
mouseDown
@Deprecated public boolean mouseDown(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
mouseDrag
@Deprecated public boolean mouseDrag(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
mouseUp
@Deprecated public boolean mouseUp(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
mouseMove
@Deprecated public boolean mouseMove(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
mouseEnter
@Deprecated public boolean mouseEnter(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
mouseExit
@Deprecated public boolean mouseExit(Event evt, int x, int y)
- Parameters:
-
evt
- the event to handle -
x
- the x coordinate -
y
- the y coordinate - Returns:
false
keyDown
@Deprecated public boolean keyDown(Event evt, int key)
- Parameters:
-
evt
- the event to handle -
key
- the key pressed - Returns:
false
keyUp
@Deprecated public boolean keyUp(Event evt, int key)
- Parameters:
-
evt
- the event to handle -
key
- the key pressed - Returns:
false
action
@Deprecated public boolean action(Event evt, Object what)
- Parameters:
-
evt
- the event to handle -
what
- the object acted on - Returns:
false
addNotify
public void addNotify()
Makes this Component
displayable by connecting it to a native screen resource. This method is called internally by the toolkit and should not be called directly by programs.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Since:
- 1.0
- See Also:
-
isDisplayable()
,removeNotify()
,invalidate()
removeNotify
public void removeNotify()
Makes this Component
undisplayable by destroying it native screen resource.
This method is called by the toolkit internally and should not be called directly by programs. Code overriding this method should call super.removeNotify
as the first line of the overriding method.
- Since:
- 1.0
- See Also:
-
isDisplayable()
,addNotify()
gotFocus
@Deprecated public boolean gotFocus(Event evt, Object what)
- Parameters:
-
evt
- the event to handle -
what
- the object focused - Returns:
false
lostFocus
@Deprecated public boolean lostFocus(Event evt, Object what)
- Parameters:
-
evt
- the event to handle -
what
- the object focused - Returns:
false
isFocusTraversable
@Deprecated public boolean isFocusTraversable()
isFocusable()
.Returns whether this Component
can become the focus owner.
- Returns:
-
true
if thisComponent
is focusable;false
otherwise - Since:
- 1.1
- See Also:
setFocusable(boolean)
isFocusable
public boolean isFocusable()
Returns whether this Component can be focused.
- Returns:
-
true
if this Component is focusable;false
otherwise. - Since:
- 1.4
- See Also:
setFocusable(boolean)
setFocusable
public void setFocusable(boolean focusable)
Sets the focusable state of this Component to the specified value. This value overrides the Component's default focusability.
- Parameters:
-
focusable
- indicates whether this Component is focusable - Since:
- 1.4
- See Also:
isFocusable()
setFocusTraversalKeys
public void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
Sets the focus traversal keys for a given traversal operation for this Component.
The default values for a Component's focus traversal keys are implementation-dependent. Sun recommends that all implementations for a particular native platform use the same default values. The recommendations for Windows and Unix are listed below. These recommendations are used in the Sun AWT implementations.
Identifier | Meaning | Default |
---|---|---|
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS | Normal forward keyboard traversal | TAB on KEY_PRESSED, CTRL-TAB on KEY_PRESSED |
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS | Normal reverse keyboard traversal | SHIFT-TAB on KEY_PRESSED, CTRL-SHIFT-TAB on KEY_PRESSED |
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS | Go up one focus traversal cycle | none |
Using the AWTKeyStroke API, client code can specify on which of two specific KeyEvents, KEY_PRESSED or KEY_RELEASED, the focus traversal operation will occur. Regardless of which KeyEvent is specified, however, all KeyEvents related to the focus traversal key, including the associated KEY_TYPED event, will be consumed, and will not be dispatched to any Component. It is a runtime error to specify a KEY_TYPED event as mapping to a focus traversal operation, or to map the same event to multiple default focus traversal operations.
If a value of null is specified for the Set, this Component inherits the Set from its parent. If all ancestors of this Component have null specified for the Set, then the current KeyboardFocusManager's default Set is used.
This method may throw a ClassCastException
if any Object
in keystrokes
is not an AWTKeyStroke
.
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS -
keystrokes
- the Set of AWTKeyStroke for the specified operation - Throws:
-
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or if keystrokes contains null, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another focus traversal operation for this Component - Since:
- 1.4
- See Also:
-
getFocusTraversalKeys(int)
,KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
getFocusTraversalKeys
public Set<AWTKeyStroke> getFocusTraversalKeys(int id)
Returns the Set of focus traversal keys for a given traversal operation for this Component. (See setFocusTraversalKeys
for a full description of each key.)
If a Set of traversal keys has not been explicitly defined for this Component, then this Component's parent's Set is returned. If no Set has been explicitly defined for any of this Component's ancestors, then the current KeyboardFocusManager's default Set is returned.
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS - Returns:
- the Set of AWTKeyStrokes for the specified operation. The Set will be unmodifiable, and may be empty. null will never be returned.
- Throws:
-
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS - Since:
- 1.4
- See Also:
-
setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
areFocusTraversalKeysSet
public boolean areFocusTraversalKeysSet(int id)
Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component. If this method returns false
, this Component is inheriting the Set from an ancestor, or from the current KeyboardFocusManager.
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS - Returns:
-
true
if the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component;false
otherwise. - Throws:
-
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS - Since:
- 1.4
setFocusTraversalKeysEnabled
public void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
Sets whether focus traversal keys are enabled for this Component. Components for which focus traversal keys are disabled receive key events for focus traversal keys. Components for which focus traversal keys are enabled do not see these events; instead, the events are automatically converted to traversal operations.
- Parameters:
-
focusTraversalKeysEnabled
- whether focus traversal keys are enabled for this Component - Since:
- 1.4
- See Also:
-
getFocusTraversalKeysEnabled()
,setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,getFocusTraversalKeys(int)
getFocusTraversalKeysEnabled
public boolean getFocusTraversalKeysEnabled()
Returns whether focus traversal keys are enabled for this Component. Components for which focus traversal keys are disabled receive key events for focus traversal keys. Components for which focus traversal keys are enabled do not see these events; instead, the events are automatically converted to traversal operations.
- Returns:
- whether focus traversal keys are enabled for this Component
- Since:
- 1.4
- See Also:
-
setFocusTraversalKeysEnabled(boolean)
,setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,getFocusTraversalKeys(int)
requestFocus
public void requestFocus()
Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event. If this request is denied because this Component's top-level Window cannot become the focused Window, the request will be remembered and will be granted when the Window is later focused by the user.
This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow
when possible.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Since:
- 1.0
- See Also:
-
requestFocusInWindow()
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocus
public void requestFocus(FocusEvent.Cause cause)
Requests by the reason of cause
that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
The focus request effect may also depend on the provided cause value. If this request is succeed the FocusEvent
generated in the result will receive the cause value specified as the argument of method. If this request is denied because this Component's top-level Window cannot become the focused Window, the request will be remembered and will be granted when the Window is later focused by the user.
This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow(FocusEvent.Cause)
when possible.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Parameters:
-
cause
- the cause why the focus is requested - Since:
- 9
- See Also:
-
FocusEvent
,FocusEvent.Cause
,requestFocusInWindow(FocusEvent.Cause)
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocus
protected boolean requestFocus(boolean temporary)
Requests that this Component
get the input focus, and that this Component
's top-level ancestor become the focused Window
. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event. If this request is denied because this component's top-level window cannot become the focused window, the request will be remembered and will be granted when the window is later focused by the user.
This method returns a boolean value. If false
is returned, the request is guaranteed to fail. If true
is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true
indicates that the request is likely to succeed, developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at all. Use KeyboardFocusManager.clearGlobalFocusOwner
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow
when possible.
Every effort will be made to ensure that FocusEvent
s generated as a result of this request will have the specified temporary value. However, because specifying an arbitrary temporary state may not be implementable on all native windowing systems, correct behavior for this method can be guaranteed only for lightweight Component
s. This method is not intended for general use, but exists instead as a hook for lightweight component libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Parameters:
-
temporary
- true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see the Focus Specification - Returns:
-
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed - Since:
- 1.4
- See Also:
-
FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocus
protected boolean requestFocus(boolean temporary, FocusEvent.Cause cause)
Requests by the reason of cause
that this Component
get the input focus, and that this Component
's top-level ancestor become the focused Window
. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event. If this request is denied because this component's top-level window cannot become the focused window, the request will be remembered and will be granted when the window is later focused by the user.
This method returns a boolean value. If false
is returned, the request is guaranteed to fail. If true
is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true
indicates that the request is likely to succeed, developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
The focus request effect may also depend on the provided cause value. If this request is succeed the {FocusEvent} generated in the result will receive the cause value specified as the argument of the method.
This method cannot be used to set the focus owner to no component at all. Use KeyboardFocusManager.clearGlobalFocusOwner
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow
when possible.
Every effort will be made to ensure that FocusEvent
s generated as a result of this request will have the specified temporary value. However, because specifying an arbitrary temporary state may not be implementable on all native windowing systems, correct behavior for this method can be guaranteed only for lightweight Component
s. This method is not intended for general use, but exists instead as a hook for lightweight component libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Parameters:
-
temporary
- true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see the Focus Specification -
cause
- the cause why the focus is requested - Returns:
-
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed - Since:
- 9
- See Also:
-
FocusEvent
,FocusEvent.Cause
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocusInWindow
public boolean requestFocusInWindow()
Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
This method returns a boolean value. If false
is returned, the request is guaranteed to fail. If true
is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the Component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true
indicates that the request is likely to succeed, developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus
when possible. Code which relies on requestFocus
may exhibit different focus behavior on different platforms.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Returns:
-
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed - Since:
- 1.4
- See Also:
-
requestFocus()
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocusInWindow
public boolean requestFocusInWindow(FocusEvent.Cause cause)
Requests by the reason of cause
that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
This method returns a boolean value. If false
is returned, the request is guaranteed to fail. If true
is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the Component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true
indicates that the request is likely to succeed, developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
The focus request effect may also depend on the provided cause value. If this request is succeed the FocusEvent
generated in the result will receive the cause value specified as the argument of the method.
This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus(FocusEvent.Cause)
when possible. Code which relies on requestFocus(FocusEvent.Cause)
may exhibit different focus behavior on different platforms.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Parameters:
-
cause
- the cause why the focus is requested - Returns:
-
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed - Since:
- 9
- See Also:
-
requestFocus(FocusEvent.Cause)
,FocusEvent
,FocusEvent.Cause
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
requestFocusInWindow
protected boolean requestFocusInWindow(boolean temporary)
Requests that this Component
get the input focus, if this Component
's top-level ancestor is already the focused Window
. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
This method returns a boolean value. If false
is returned, the request is guaranteed to fail. If true
is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true
indicates that the request is likely to succeed, developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at all. Use KeyboardFocusManager.clearGlobalFocusOwner
instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus
when possible. Code which relies on requestFocus
may exhibit different focus behavior on different platforms.
Every effort will be made to ensure that FocusEvent
s generated as a result of this request will have the specified temporary value. However, because specifying an arbitrary temporary state may not be implementable on all native windowing systems, correct behavior for this method can be guaranteed only for lightweight components. This method is not intended for general use, but exists instead as a hook for lightweight component libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the other requestFocus
methods of Component
being invoked.
- Parameters:
-
temporary
- true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see the Focus Specification - Returns:
-
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed - Since:
- 1.4
- See Also:
-
requestFocus()
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
getFocusCycleRootAncestor
public Container getFocusCycleRootAncestor()
Returns the Container which is the focus cycle root of this Component's focus traversal cycle. Each focus traversal cycle has only a single focus cycle root and each Component which is not a Container belongs to only a single focus traversal cycle. Containers which are focus cycle roots belong to two cycles: one rooted at the Container itself, and one rooted at the Container's nearest focus-cycle-root ancestor. For such Containers, this method will return the Container's nearest focus-cycle- root ancestor.
- Returns:
- this Component's nearest focus-cycle-root ancestor
- Since:
- 1.4
- See Also:
Container.isFocusCycleRoot()
isFocusCycleRoot
public boolean isFocusCycleRoot(Container container)
Returns whether the specified Container is the focus cycle root of this Component's focus traversal cycle. Each focus traversal cycle has only a single focus cycle root and each Component which is not a Container belongs to only a single focus traversal cycle.
- Parameters:
-
container
- the Container to be tested - Returns:
-
true
if the specified Container is a focus-cycle- root of this Component;false
otherwise - Since:
- 1.4
- See Also:
Container.isFocusCycleRoot()
transferFocus
public void transferFocus()
Transfers the focus to the next component, as though this Component were the focus owner.
- Since:
- 1.1
- See Also:
requestFocus()
nextFocus
@Deprecated public void nextFocus()
transferFocusBackward
public void transferFocusBackward()
Transfers the focus to the previous component, as though this Component were the focus owner.
- Since:
- 1.4
- See Also:
requestFocus()
transferFocusUpCycle
public void transferFocusUpCycle()
Transfers the focus up one focus traversal cycle. Typically, the focus owner is set to this Component's focus cycle root, and the current focus cycle root is set to the new focus owner's focus cycle root. If, however, this Component's focus cycle root is a Window, then the focus owner is set to the focus cycle root's default Component to focus, and the current focus cycle root is unchanged.
- Since:
- 1.4
- See Also:
-
requestFocus()
,Container.isFocusCycleRoot()
,Container.setFocusCycleRoot(boolean)
hasFocus
public boolean hasFocus()
Returns true
if this Component
is the focus owner. This method is obsolete, and has been replaced by isFocusOwner()
.
- Returns:
-
true
if thisComponent
is the focus owner;false
otherwise - Since:
- 1.2
isFocusOwner
public boolean isFocusOwner()
Returns true
if this Component
is the focus owner.
- Returns:
-
true
if thisComponent
is the focus owner;false
otherwise - Since:
- 1.4
add
public void add(PopupMenu popup)
Adds the specified popup menu to the component.
- Parameters:
-
popup
- the popup menu to be added to the component. - Throws:
-
NullPointerException
- ifpopup
isnull
- Since:
- 1.1
- See Also:
remove(MenuComponent)
remove
public void remove(MenuComponent popup)
Removes the specified popup menu from the component.
- Specified by:
-
remove
in interfaceMenuContainer
- Parameters:
-
popup
- the popup menu to be removed - Since:
- 1.1
- See Also:
add(PopupMenu)
paramString
protected String paramString()
Returns a string representing the state of this component. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null
.
- Returns:
- a string representation of this component's state
- Since:
- 1.0
toString
public String toString()
Returns a string representation of this component and its values.
list
public void list()
Prints a listing of this component to the standard system output stream System.out
.
- Since:
- 1.0
- See Also:
System.out
list
public void list(PrintStream out)
Prints a listing of this component to the specified output stream.
- Parameters:
-
out
- a print stream - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.0
list
public void list(PrintStream out, int indent)
Prints out a list, starting at the specified indentation, to the specified print stream.
- Parameters:
-
out
- a print stream -
indent
- number of spaces to indent - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.0
- See Also:
PrintStream.println(java.lang.Object)
list
public void list(PrintWriter out)
Prints a listing to the specified print writer.
- Parameters:
-
out
- the print writer to print to - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.1
list
public void list(PrintWriter out, int indent)
Prints out a list, starting at the specified indentation, to the specified print writer.
- Parameters:
-
out
- the print writer to print to -
indent
- the number of spaces to indent - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.1
- See Also:
PrintStream.println(java.lang.Object)
addPropertyChangeListener
public void addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list. The listener is registered for all bound properties of this class, including the following:
- this Component's font ("font")
- this Component's background color ("background")
- this Component's foreground color ("foreground")
- this Component's focusability ("focusable")
- this Component's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Component's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Component's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Component's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
- this Component's preferred size ("preferredSize")
- this Component's minimum size ("minimumSize")
- this Component's maximum size ("maximumSize")
- this Component's name ("name")
Component
is inheriting a bound property, then no event will be fired in response to a change in the inherited property.
If listener
is null
, no exception is thrown and no action is performed.
- Parameters:
-
listener
- the property change listener to be added - See Also:
-
removePropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
,addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
removePropertyChangeListener
public void removePropertyChangeListener(PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list. This method should be used to remove PropertyChangeListeners that were registered for all bound properties of this class.
If listener is null, no exception is thrown and no action is performed.
- Parameters:
-
listener
- the PropertyChangeListener to be removed - See Also:
-
addPropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
,removePropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)
getPropertyChangeListeners
public PropertyChangeListener[] getPropertyChangeListeners()
Returns an array of all the property change listeners registered on this component.
- Returns:
- all of this component's
PropertyChangeListener
s or an empty array if no property change listeners are currently registered - Since:
- 1.4
- See Also:
-
addPropertyChangeListener(java.beans.PropertyChangeListener)
,removePropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,PropertyChangeSupport.getPropertyChangeListeners()
addPropertyChangeListener
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list for a specific property. The specified property may be user-defined, or one of the following:
- this Component's font ("font")
- this Component's background color ("background")
- this Component's foreground color ("foreground")
- this Component's focusability ("focusable")
- this Component's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Component's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Component's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Component's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
Component
is inheriting a bound property, then no event will be fired in response to a change in the inherited property.
If propertyName
or listener
is null
, no exception is thrown and no action is taken.
- Parameters:
-
propertyName
- one of the property names listed above -
listener
- the property change listener to be added - See Also:
-
removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
removePropertyChangeListener
public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
Removes a PropertyChangeListener
from the listener list for a specific property. This method should be used to remove PropertyChangeListener
s that were registered for a specific bound property.
If propertyName
or listener
is null
, no exception is thrown and no action is taken.
- Parameters:
-
propertyName
- a valid property name -
listener
- the PropertyChangeListener to be removed - See Also:
-
addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,removePropertyChangeListener(java.beans.PropertyChangeListener)
getPropertyChangeListeners
public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
Returns an array of all the listeners which have been associated with the named property.
- Parameters:
-
propertyName
- the property name - Returns:
- all of the
PropertyChangeListener
s associated with the named property; if no such listeners have been added or ifpropertyName
isnull
, an empty array is returned - Since:
- 1.4
- See Also:
-
addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
firePropertyChange
protected void firePropertyChange(String propertyName, Object oldValue, Object newValue)
Support for reporting bound property changes for Object properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
- Parameters:
-
propertyName
- the property whose value has changed -
oldValue
- the property's previous value -
newValue
- the property's new value
firePropertyChange
protected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
Support for reporting bound property changes for boolean properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
- Parameters:
-
propertyName
- the property whose value has changed -
oldValue
- the property's previous value -
newValue
- the property's new value - Since:
- 1.4
firePropertyChange
protected void firePropertyChange(String propertyName, int oldValue, int newValue)
Support for reporting bound property changes for integer properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
- Parameters:
-
propertyName
- the property whose value has changed -
oldValue
- the property's previous value -
newValue
- the property's new value - Since:
- 1.4
firePropertyChange
public void firePropertyChange(String propertyName, byte oldValue, byte newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a byte) -
newValue
- the new value of the property (as a byte) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
firePropertyChange
public void firePropertyChange(String propertyName, char oldValue, char newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a char) -
newValue
- the new value of the property (as a char) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
firePropertyChange
public void firePropertyChange(String propertyName, short oldValue, short newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a short) -
newValue
- the new value of the property (as a short) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
firePropertyChange
public void firePropertyChange(String propertyName, long oldValue, long newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a long) -
newValue
- the new value of the property (as a long) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
firePropertyChange
public void firePropertyChange(String propertyName, float oldValue, float newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a float) -
newValue
- the new value of the property (as a float) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
firePropertyChange
public void firePropertyChange(String propertyName, double oldValue, double newValue)
Reports a bound property change.
- Parameters:
-
propertyName
- the programmatic name of the property that was changed -
oldValue
- the old value of the property (as a double) -
newValue
- the new value of the property (as a double) - Since:
- 1.5
- See Also:
firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
setComponentOrientation
public void setComponentOrientation(ComponentOrientation o)
Sets the language-sensitive orientation that is to be used to order the elements or text within this component. Language-sensitive LayoutManager
and Component
subclasses will use this property to determine how to lay out and draw components.
At construction time, a component's orientation is set to ComponentOrientation.UNKNOWN
, indicating that it has not been specified explicitly. The UNKNOWN orientation behaves the same as ComponentOrientation.LEFT_TO_RIGHT
.
To set the orientation of a single component, use this method. To set the orientation of an entire component hierarchy, use applyComponentOrientation
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
o
- the orientation to be set - See Also:
-
ComponentOrientation
,invalidate()
getComponentOrientation
public ComponentOrientation getComponentOrientation()
Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component. LayoutManager
and Component
subclasses that wish to respect orientation should call this method to get the component's orientation before performing layout or drawing.
- Returns:
- the orientation to order the elements or text
- See Also:
ComponentOrientation
applyComponentOrientation
public void applyComponentOrientation(ComponentOrientation orientation)
Sets the ComponentOrientation
property of this component and all components contained within it.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
orientation
- the new component orientation of this component and the components contained within it. - Throws:
-
NullPointerException
- iforientation
is null. - Since:
- 1.4
- See Also:
-
setComponentOrientation(java.awt.ComponentOrientation)
,getComponentOrientation()
,invalidate()
getAccessibleContext
public AccessibleContext getAccessibleContext()
Gets the AccessibleContext
associated with this Component
. The method implemented by this base class returns null. Classes that extend Component
should implement this method to return the AccessibleContext
associated with the subclass.
- Returns:
- the
AccessibleContext
of thisComponent
- Since:
- 1.3
setMixingCutoutShape
public void setMixingCutoutShape(Shape shape)
Sets a 'mixing-cutout' shape for this lightweight component. This method is used exclusively for the purposes of the Heavyweight/Lightweight Components Mixing feature and will have no effect if applied to a heavyweight component. By default a lightweight component is treated as an opaque rectangle for the purposes of the Heavyweight/Lightweight Components Mixing feature. This method enables developers to set an arbitrary shape to be cut out from heavyweight components positioned underneath the lightweight component in the z-order.
The shape
argument may have the following values:
-
null
- reverts the default cutout shape (the rectangle equal to the component'sgetBounds()
) -
empty-shape - does not cut out anything from heavyweight components. This makes this lightweight component effectively transparent. Note that descendants of the lightweight component still affect the shapes of heavyweight components. An example of an empty-shape is
new Rectangle()
. - non-empty-shape - the given shape will be cut out from heavyweight components.
The most common example when the 'mixing-cutout' shape is needed is a glass pane component. The JRootPane.setGlassPane(java.awt.Component)
method automatically sets the empty-shape as the 'mixing-cutout' shape for the given glass pane component. If a developer needs some other 'mixing-cutout' shape for the glass pane (which is rare), this must be changed manually after installing the glass pane to the root pane.
- Parameters:
-
shape
- the new 'mixing-cutout' shape - Since:
- 9