Class Container
- java.lang.Object
-
- java.awt.Component
-
- java.awt.Container
- All Implemented Interfaces:
-
ImageObserver
,MenuContainer
,Serializable
- Direct Known Subclasses:
-
BasicSplitPaneDivider
,CellRendererPane
,DefaultTreeCellEditor.EditorContainer
,JComponent
,Panel
,ScrollPane
,Window
public class Container extends Component
A generic Abstract Window Toolkit(AWT) container object is a component that can contain other AWT components.
Components added to a container are tracked in a list. The order of the list will define the components' front-to-back stacking order within the container. If no index is specified when adding a component to a container, it will be added to the end of the list (and hence to the bottom of the stacking order).
Note: 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.
- Since:
- 1.0
- See Also:
-
add(java.awt.Component, int)
,getComponent(int)
,LayoutManager
, Serialized Form
Nested Class Summary
Modifier and Type | Class | Description |
---|---|---|
protected class | Container.AccessibleAWTContainer | Inner class of Container used to provide default support for accessibility. |
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
Field Summary
Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor Summary
Constructor | Description |
---|---|
Container() | Constructs a new Container. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
Component | add(Component comp) | Appends the specified component to the end of this container. |
Component | add(Component comp,
int index) | Adds the specified component to this container at the given position. |
void | add(Component comp,
Object constraints) | Adds the specified component to the end of this container. |
void | add(Component comp,
Object constraints,
int index) | Adds the specified component to this container with the specified constraints at the specified index. |
Component | add(String name,
Component comp) | Adds the specified component to this container. |
void | addContainerListener(ContainerListener l) | Adds the specified container listener to receive container events from this container. |
protected void | addImpl(Component comp,
Object constraints,
int index) | Adds the specified component to this container at the specified index. |
void | addNotify() | Makes this Container displayable by connecting it to a native screen resource. |
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 o) | 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 Container. |
int | countComponents() | Deprecated. As of JDK version 1.1, replaced by getComponentCount(). |
void | deliverEvent(Event e) | Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e)
|
void | doLayout() | Causes this container to lay out its components. |
Component | findComponentAt(int x,
int y) | Locates the visible child component that contains the specified position. |
Component | findComponentAt(Point p) | Locates the visible child component that contains the specified point. |
float | getAlignmentX() | Returns the alignment along the x axis. |
float | getAlignmentY() | Returns the alignment along the y axis. |
Component | getComponent(int n) | Gets the nth component in this container. |
Component | getComponentAt(int x,
int y) | Locates the component that contains the x,y position. |
Component | getComponentAt(Point p) | Gets the component that contains the specified point. |
int | getComponentCount() | Gets the number of components in this panel. |
Component[] | getComponents() | Gets all the components in this container. |
int | getComponentZOrder(Component comp) | Returns the z-order index of the component inside the container. |
ContainerListener[] | getContainerListeners() | Returns an array of all the container listeners registered on this container. |
Set<AWTKeyStroke> | getFocusTraversalKeys(int id) | Returns the Set of focus traversal keys for a given traversal operation for this Container. |
FocusTraversalPolicy | getFocusTraversalPolicy() | Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root. |
Insets | getInsets() | Determines the insets of this container, which indicate the size of the container's border. |
LayoutManager | getLayout() | Gets the layout manager for this container. |
<T extends EventListener> | getListeners(Class<T> listenerType) | Returns an array of all the objects currently registered as |
Dimension | getMaximumSize() | Returns the maximum size of this container. |
Dimension | getMinimumSize() | Returns the minimum size of this container. |
Point | getMousePosition(boolean allowChildren) | Returns the position of the mouse pointer in this |
Dimension | getPreferredSize() | Returns the preferred size of this container. |
Insets | insets() | Deprecated. As of JDK version 1.1, replaced by getInsets() . |
void | invalidate() | Invalidates the container. |
boolean | isAncestorOf(Component c) | Checks if the component is contained in the component hierarchy of this container. |
boolean | isFocusCycleRoot() | Returns whether this Container is the root of a focus traversal cycle. |
boolean | isFocusCycleRoot(Container container) | Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle. |
boolean | isFocusTraversalPolicyProvider() | Returns whether this container provides focus traversal policy. |
boolean | isFocusTraversalPolicySet() | Returns whether the focus traversal policy has been explicitly set for this Container. |
boolean | isValidateRoot() | Indicates if this container is a validate root. |
void | layout() | Deprecated. As of JDK version 1.1, replaced by doLayout() . |
void | list(PrintStream out,
int indent) | Prints a listing of this container to the specified output stream. |
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) . |
Dimension | minimumSize() | Deprecated. As of JDK version 1.1, replaced by getMinimumSize() . |
void | paint(Graphics g) | Paints the container. |
void | paintComponents(Graphics g) | Paints each of the components in this container. |
protected String | paramString() | Returns a string representing the state of this |
Dimension | preferredSize() | Deprecated. As of JDK version 1.1, replaced by getPreferredSize() . |
void | print(Graphics g) | Prints the container. |
void | printComponents(Graphics g) | Prints each of the components in this container. |
protected void | processContainerEvent(ContainerEvent e) | Processes container events occurring on this container by dispatching them to any registered ContainerListener objects. |
protected void | processEvent(AWTEvent e) | Processes events on this container. |
void | remove(int index) | Removes the component, specified by |
void | remove(Component comp) | Removes the specified component from this container. |
void | removeAll() | Removes all the components from this container. |
void | removeContainerListener(ContainerListener l) | Removes the specified container listener so it no longer receives container events from this container. |
void | removeNotify() | Makes this Container undisplayable by removing its connection to its native screen resource. |
void | setComponentZOrder(Component comp,
int index) | Moves the specified component to the specified z-order index in the container. |
void | setFocusCycleRoot(boolean focusCycleRoot) | Sets whether this Container is the root of a focus traversal cycle. |
void | setFocusTraversalKeys(int id,
Set<? extends AWTKeyStroke> keystrokes) | Sets the focus traversal keys for a given traversal operation for this Container. |
void | setFocusTraversalPolicy(FocusTraversalPolicy policy) | Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root. |
void | setFocusTraversalPolicyProvider(boolean provider) | Sets whether this container will be used to provide focus traversal policy. |
void | setFont(Font f) | Sets the font of this container. |
void | setLayout(LayoutManager mgr) | Sets the layout manager for this container. |
void | transferFocusDownCycle() | Transfers the focus down one focus traversal cycle. |
void | update(Graphics g) | Updates the container. |
void | validate() | Validates this container and all of its subcomponents. |
protected void | validateTree() | Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid). |
Methods declared in class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAccessibleContext, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Constructor Detail
Container
public Container()
Constructs a new Container. Containers can be extended directly, but are lightweight in this case and must be contained by a parent somewhere higher up in the component tree that is native. (such as Frame for example).
Method Detail
getComponentCount
public int getComponentCount()
Gets the number of components in this panel.
Note: This method should be called under AWT tree lock.
- Returns:
- the number of components in this panel.
- Since:
- 1.1
- See Also:
-
getComponent(int)
,Component.getTreeLock()
countComponents
@Deprecated public int countComponents()
Returns the number of components in this container.
- Returns:
- the number of components in this container
getComponent
public Component getComponent(int n)
Gets the nth component in this container.
Note: This method should be called under AWT tree lock.
- Parameters:
-
n
- the index of the component to get. - Returns:
- the nth component in this container.
- Throws:
-
ArrayIndexOutOfBoundsException
- if the nth value does not exist. - See Also:
Component.getTreeLock()
getComponents
public Component[] getComponents()
Gets all the components in this container.
Note: This method should be called under AWT tree lock.
- Returns:
- an array of all the components in this container.
- See Also:
Component.getTreeLock()
getInsets
public Insets getInsets()
Determines the insets of this container, which indicate the size of the container's border.
A Frame
object, for example, has a top inset that corresponds to the height of the frame's title bar.
- Returns:
- the insets of this container.
- Since:
- 1.1
- See Also:
-
Insets
,LayoutManager
insets
@Deprecated public Insets insets()
getInsets()
.Returns the insets for this container.
- Returns:
- the insets for this container
add
public Component add(Component comp)
Appends the specified component to the end of this container. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int)
.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
comp
- the component to be added - Returns:
- the component argument
- Throws:
-
NullPointerException
- ifcomp
isnull
- See Also:
-
addImpl(java.awt.Component, java.lang.Object, int)
,invalidate()
,validate()
,JComponent.revalidate()
add
public Component add(String name, Component comp)
Adds the specified component to this container. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int)
.
This method is obsolete as of 1.1. Please use the method add(Component, Object)
instead.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
name
- the name of the component to be added -
comp
- the component to be added - Returns:
- the component added
- Throws:
-
NullPointerException
- ifcomp
isnull
- See Also:
-
add(Component, Object)
,invalidate()
add
public Component add(Component comp, int index)
Adds the specified component to this container at the given position. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int)
.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
comp
- the component to be added -
index
- the position at which to insert the component, or-1
to append the component to the end - Returns:
- the component
comp
- Throws:
-
NullPointerException
- ifcomp
isnull
-
IllegalArgumentException
- ifindex
is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int)
for details) - See Also:
-
addImpl(java.awt.Component, java.lang.Object, int)
,remove(int)
,invalidate()
,validate()
,JComponent.revalidate()
setComponentZOrder
public void setComponentZOrder(Component comp, int index)
Moves the specified component to the specified z-order index in the container. The z-order determines the order that components are painted; the component with the highest z-order paints first and the component with the lowest z-order paints last. Where components overlap, the component with the lower z-order paints over the component with the higher z-order.
If the component is a child of some other container, it is removed from that container before being added to this container. The important difference between this method and java.awt.Container.add(Component, int)
is that this method doesn't call removeNotify
on the component while removing it from its previous container unless necessary and when allowed by the underlying native windowing system. This way, if the component has the keyboard focus, it maintains the focus when moved to the new position.
This property is guaranteed to apply only to lightweight non-Container
components.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
Note: Not all platforms support changing the z-order of heavyweight components from one container into another without the call to removeNotify
. There is no way to detect whether a platform supports this, so developers shouldn't make any assumptions.
- Parameters:
-
comp
- the component to be moved -
index
- the position in the container's list to insert the component, wheregetComponentCount()
appends to the end - Throws:
-
NullPointerException
- ifcomp
isnull
-
IllegalArgumentException
- ifcomp
is one of the container's parents -
IllegalArgumentException
- ifindex
is not in the range[0, getComponentCount()]
for moving between containers, or not in the range[0, getComponentCount()-1]
for moving inside a container -
IllegalArgumentException
- if adding a container to itself -
IllegalArgumentException
- if adding aWindow
to a container - Since:
- 1.5
- See Also:
-
getComponentZOrder(java.awt.Component)
,invalidate()
getComponentZOrder
public int getComponentZOrder(Component comp)
Returns the z-order index of the component inside the container. The higher a component is in the z-order hierarchy, the lower its index. The component with the lowest z-order index is painted last, above all other child components.
- Parameters:
-
comp
- the component being queried - Returns:
- the z-order index of the component; otherwise returns -1 if the component is
null
or doesn't belong to the container - Since:
- 1.5
- See Also:
setComponentZOrder(java.awt.Component, int)
add
public void add(Component comp, Object constraints)
Adds the specified component to the end of this container. Also notifies the layout manager to add the component to this container's layout using the specified constraints object. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int)
.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
comp
- the component to be added -
constraints
- an object expressing layout constraints for this component - Throws:
-
NullPointerException
- ifcomp
isnull
- Since:
- 1.1
- See Also:
-
addImpl(java.awt.Component, java.lang.Object, int)
,invalidate()
,validate()
,JComponent.revalidate()
,LayoutManager
add
public void add(Component comp, Object constraints, int index)
Adds the specified component to this container with the specified constraints at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int)
.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
comp
- the component to be added -
constraints
- an object expressing layout constraints for this -
index
- the position in the container's list at which to insert the component;-1
means insert at the end component - Throws:
-
NullPointerException
- ifcomp
isnull
-
IllegalArgumentException
- ifindex
is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int)
for details) - See Also:
-
addImpl(java.awt.Component, java.lang.Object, int)
,invalidate()
,validate()
,JComponent.revalidate()
,remove(int)
,LayoutManager
addImpl
protected void addImpl(Component comp, Object constraints, int index)
Adds the specified component to this container at the specified index. This method also notifies the layout manager to add the component to this container's layout using the specified constraints object via the addLayoutComponent
method.
The constraints are defined by the particular layout manager being used. For example, the BorderLayout
class defines five constraints: BorderLayout.NORTH
, BorderLayout.SOUTH
, BorderLayout.EAST
, BorderLayout.WEST
, and BorderLayout.CENTER
.
The GridBagLayout
class requires a GridBagConstraints
object. Failure to pass the correct type of constraints object results in an IllegalArgumentException
.
If the current layout manager implements LayoutManager2
, then LayoutManager2.addLayoutComponent(Component,Object)
is invoked on it. If the current layout manager does not implement LayoutManager2
, and constraints is a String
, then LayoutManager.addLayoutComponent(String,Component)
is invoked on it.
If the component is not an ancestor of this container and has a non-null parent, it is removed from its current parent before it is added to this container.
This is the method to override if a program needs to track every add request to a container as all other add methods defer to this one. An overriding method should usually include a call to the superclass's version of the method:
super.addImpl(comp, constraints, index)
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
-
comp
- the component to be added -
constraints
- an object expressing layout constraints for this component -
index
- the position in the container's list at which to insert the component, where-1
means append to the end - Throws:
-
IllegalArgumentException
- ifindex
is invalid; ifcomp
is a child of this container, the valid range is[-1, getComponentCount()-1]
; if component is not a child of this container, the valid range is[-1, getComponentCount()]
-
IllegalArgumentException
- ifcomp
is an ancestor of this container -
IllegalArgumentException
- if adding a window to a container -
NullPointerException
- ifcomp
isnull
- Since:
- 1.1
- See Also:
-
add(Component)
,add(Component, int)
,add(Component, java.lang.Object)
,invalidate()
,LayoutManager
,LayoutManager2
remove
public void remove(int index)
Removes the component, specified by index
, from this container. This method also notifies the layout manager to remove the component from this container's layout via the removeLayoutComponent
method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- Parameters:
-
index
- the index of the component to be removed - Throws:
-
ArrayIndexOutOfBoundsException
- ifindex
is not in range[0, getComponentCount()-1]
- Since:
- 1.1
- See Also:
-
add(java.awt.Component)
,invalidate()
,validate()
,getComponentCount()
remove
public void remove(Component comp)
Removes the specified component from this container. This method also notifies the layout manager to remove the component from this container's layout via the removeLayoutComponent
method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- Parameters:
-
comp
- the component to be removed - Throws:
-
NullPointerException
- ifcomp
isnull
- See Also:
-
add(java.awt.Component)
,invalidate()
,validate()
,remove(int)
removeAll
public void removeAll()
Removes all the components from this container. This method also notifies the layout manager to remove the components from this container's layout via the removeLayoutComponent
method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- See Also:
-
add(java.awt.Component)
,remove(int)
,invalidate()
getLayout
public LayoutManager getLayout()
Gets the layout manager for this container.
- Returns:
- the current layout manager for this container
- See Also:
-
doLayout()
,setLayout(java.awt.LayoutManager)
setLayout
public void setLayout(LayoutManager mgr)
Sets the layout manager for this container.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
-
mgr
- the specified layout manager - See Also:
-
doLayout()
,getLayout()
,invalidate()
doLayout
public void doLayout()
Causes this container to lay out its components. Most programs should not call this method directly, but should invoke the validate
method instead.
- Overrides:
-
doLayout
in classComponent
- Since:
- 1.1
- See Also:
-
LayoutManager.layoutContainer(java.awt.Container)
,setLayout(java.awt.LayoutManager)
,validate()
layout
@Deprecated public void layout()
doLayout()
.isValidateRoot
public boolean isValidateRoot()
Indicates if this container is a validate root.
Layout-related changes, such as bounds of the validate root descendants, do not affect the layout of the validate root parent. This peculiarity enables the invalidate()
method to stop invalidating the component hierarchy when the method encounters a validate root. However, to preserve backward compatibility this new optimized behavior is enabled only when the java.awt.smartInvalidate
system property value is set to true
.
If a component hierarchy contains validate roots and the new optimized invalidate()
behavior is enabled, the validate()
method must be invoked on the validate root of a previously invalidated component to restore the validity of the hierarchy later. Otherwise, calling the validate()
method on the top-level container (such as a Frame
object) should be used to restore the validity of the component hierarchy.
The Window
class and the Applet
class are the validate roots in AWT. Swing introduces more validate roots.
- Returns:
- whether this container is a validate root
- Since:
- 1.7
- See Also:
-
invalidate()
,Component.invalidate()
,JComponent.isValidateRoot()
,JComponent.revalidate()
invalidate
public void invalidate()
Invalidates the container.
If the LayoutManager
installed on this container is an instance of the LayoutManager2
interface, then the LayoutManager2.invalidateLayout(Container)
method is invoked on it supplying this Container
as the argument.
Afterwards this method marks this container invalid, and invalidates its ancestors. See the Component.invalidate()
method for more details.
- Overrides:
-
invalidate
in classComponent
- See Also:
-
validate()
,layout()
,LayoutManager2
validate
public void validate()
Validates this container and all of its subcomponents.
Validating a container means laying out its subcomponents. Layout-related changes, such as setting the bounds of a component, or adding a component to the container, invalidate the container automatically. Note that the ancestors of the container may be invalidated also (see Component.invalidate()
for details.) Therefore, to restore the validity of the hierarchy, the
validate()
method should be invoked on the top-most invalid container of the hierarchy.
Validating the container may be a quite time-consuming operation. For performance reasons a developer may postpone the validation of the hierarchy till a set of layout-related operations completes, e.g. after adding all the children to the container.
If this Container
is not valid, this method invokes the validateTree
method and marks this Container
as valid. Otherwise, no action is performed.
- Overrides:
-
validate
in classComponent
- See Also:
-
add(java.awt.Component)
,invalidate()
,isValidateRoot()
,JComponent.revalidate()
,validateTree()
validateTree
protected void validateTree()
Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid). Synchronization should be provided by the method that calls this one: validate
.
- See Also:
-
doLayout()
,validate()
setFont
public void setFont(Font f)
Sets the font of this container.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Overrides:
-
setFont
in classComponent
- Parameters:
-
f
- The font to become this container's font. - Since:
- 1.0
- See Also:
-
Component.getFont()
,invalidate()
getPreferredSize
public Dimension getPreferredSize()
Returns the preferred size of this container. If the preferred size has not been set explicitly by Component.setPreferredSize(Dimension)
and this Container
has a non-null
LayoutManager
, then LayoutManager.preferredLayoutSize(Container)
is used to calculate the preferred size.
Note: some implementations may cache the value returned from the LayoutManager
. Implementations that cache need not invoke preferredLayoutSize
on the LayoutManager
every time this method is invoked, rather the LayoutManager
will only be queried after the Container
becomes invalid.
- Overrides:
-
getPreferredSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the preferred size of this container. - See Also:
-
getMinimumSize()
,getMaximumSize()
,getLayout()
,LayoutManager.preferredLayoutSize(Container)
,Component.getPreferredSize()
preferredSize
@Deprecated public Dimension preferredSize()
getPreferredSize()
.Description copied from class: Component
Returns the component's preferred size.
- Overrides:
-
preferredSize
in classComponent
- Returns:
- the component's preferred size
getMinimumSize
public Dimension getMinimumSize()
Returns the minimum size of this container. If the minimum size has not been set explicitly by Component.setMinimumSize(Dimension)
and this Container
has a non-null
LayoutManager
, then LayoutManager.minimumLayoutSize(Container)
is used to calculate the minimum size.
Note: some implementations may cache the value returned from the LayoutManager
. Implementations that cache need not invoke minimumLayoutSize
on the LayoutManager
every time this method is invoked, rather the LayoutManager
will only be queried after the Container
becomes invalid.
- Overrides:
-
getMinimumSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the minimum size of this container. - Since:
- 1.1
- See Also:
-
getPreferredSize()
,getMaximumSize()
,getLayout()
,LayoutManager.minimumLayoutSize(Container)
,Component.getMinimumSize()
minimumSize
@Deprecated public Dimension minimumSize()
getMinimumSize()
.Description copied from class: Component
Returns the minimum size of this component.
- Overrides:
-
minimumSize
in classComponent
- Returns:
- the minimum size of this component
getMaximumSize
public Dimension getMaximumSize()
Returns the maximum size of this container. If the maximum size has not been set explicitly by Component.setMaximumSize(Dimension)
and the LayoutManager
installed on this Container
is an instance of LayoutManager2
, then LayoutManager2.maximumLayoutSize(Container)
is used to calculate the maximum size.
Note: some implementations may cache the value returned from the LayoutManager2
. Implementations that cache need not invoke maximumLayoutSize
on the LayoutManager2
every time this method is invoked, rather the LayoutManager2
will only be queried after the Container
becomes invalid.
- Overrides:
-
getMaximumSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the maximum size of this container. - See Also:
-
getPreferredSize()
,getMinimumSize()
,getLayout()
,LayoutManager2.maximumLayoutSize(Container)
,Component.getMaximumSize()
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.
- Overrides:
-
getAlignmentX
in classComponent
- 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.
- Overrides:
-
getAlignmentY
in classComponent
- Returns:
- the vertical alignment of this component
paint
public void paint(Graphics g)
Paints the container. This forwards the paint to any lightweight components that are children of this container. If this method is reimplemented, super.paint(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, paint() will not be forwarded to that child.
- Overrides:
-
paint
in classComponent
- Parameters:
-
g
- the specified Graphics window - See Also:
Component.update(Graphics)
update
public void update(Graphics g)
Updates the container. This forwards the update to any lightweight components that are children of this container. If this method is reimplemented, super.update(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, update() will not be forwarded to that child.
- Overrides:
-
update
in classComponent
- Parameters:
-
g
- the specified Graphics window - See Also:
Component.update(Graphics)
public void print(Graphics g)
Prints the container. This forwards the print to any lightweight components that are children of this container. If this method is reimplemented, super.print(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, print() will not be forwarded to that child.
- Overrides:
-
print
in classComponent
- Parameters:
-
g
- the specified Graphics window - See Also:
Component.update(Graphics)
paintComponents
public void paintComponents(Graphics g)
Paints each of the components in this container.
- Parameters:
-
g
- the graphics context. - See Also:
-
Component.paint(java.awt.Graphics)
,Component.paintAll(java.awt.Graphics)
printComponents
public void printComponents(Graphics g)
Prints each of the components in this container.
- Parameters:
-
g
- the graphics context. - See Also:
-
Component.print(java.awt.Graphics)
,Component.printAll(java.awt.Graphics)
addContainerListener
public void addContainerListener(ContainerListener l)
Adds the specified container listener to receive container events from this container. 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 container listener - See Also:
-
removeContainerListener(java.awt.event.ContainerListener)
,getContainerListeners()
removeContainerListener
public void removeContainerListener(ContainerListener l)
Removes the specified container listener so it no longer receives container events from this container. 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 container listener - See Also:
-
addContainerListener(java.awt.event.ContainerListener)
,getContainerListeners()
getContainerListeners
public ContainerListener[] getContainerListeners()
Returns an array of all the container listeners registered on this container.
- Returns:
- all of this container's
ContainerListener
s or an empty array if no container listeners are currently registered - Since:
- 1.4
- See Also:
-
addContainerListener(java.awt.event.ContainerListener)
,removeContainerListener(java.awt.event.ContainerListener)
getListeners
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListener
s upon this Container
. 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 Container c
for its container listeners with the following code:
ContainerListener[] cls = (ContainerListener[])(c.getListeners(ContainerListener.class));If no such listeners exist, this method returns an empty array.
- Overrides:
-
getListeners
in classComponent
- 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 container, 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:
getContainerListeners()
processEvent
protected void processEvent(AWTEvent e)
Processes events on this container. If the event is a ContainerEvent
, it invokes the processContainerEvent
method, else it invokes its superclass's processEvent
.
Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
- Overrides:
-
processEvent
in classComponent
- Parameters:
-
e
- the event - See Also:
-
Component.processComponentEvent(java.awt.event.ComponentEvent)
,Component.processFocusEvent(java.awt.event.FocusEvent)
,Component.processKeyEvent(java.awt.event.KeyEvent)
,Component.processMouseEvent(java.awt.event.MouseEvent)
,Component.processMouseMotionEvent(java.awt.event.MouseEvent)
,Component.processInputMethodEvent(java.awt.event.InputMethodEvent)
,Component.processHierarchyEvent(java.awt.event.HierarchyEvent)
,Component.processMouseWheelEvent(java.awt.event.MouseWheelEvent)
processContainerEvent
protected void processContainerEvent(ContainerEvent e)
Processes container events occurring on this container by dispatching them to any registered ContainerListener objects. NOTE: This method will not be called unless container events are enabled for this component; this happens when one of the following occurs:
- A ContainerListener object is registered via
addContainerListener
- Container 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 container event - See Also:
Component.enableEvents(long)
deliverEvent
@Deprecated public void deliverEvent(Event e)
dispatchEvent(AWTEvent e)
- Overrides:
-
deliverEvent
in classComponent
- Parameters:
-
e
- the event to deliver
getComponentAt
public Component getComponentAt(int x, int y)
Locates the component that contains the x,y position. The top-most child component is returned in the case where there is overlap in the components. This is determined by finding the component closest to the index 0 that claims to contain the given point via Component.contains(), except that Components which have native peers take precedence over those which do not (i.e., lightweight Components).
- Overrides:
-
getComponentAt
in classComponent
- Parameters:
-
x
- the x coordinate -
y
- the y coordinate - Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned; otherwise the top-most child is returned.
- Since:
- 1.1
- See Also:
Component.contains(int, int)
locate
@Deprecated public Component locate(int x, int y)
getComponentAt(int, int)
.Description copied from class: Component
Returns the component occupying the position specified (this component, or immediate child component, or null if neither of the first two occupies the location).
- Overrides:
-
locate
in classComponent
- 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)
Gets the component that contains the specified point.
- Overrides:
-
getComponentAt
in classComponent
- Parameters:
-
p
- the point. - Returns:
- returns the component that contains the point, or
null
if the component does not contain the point. - Since:
- 1.1
- See Also:
Component.contains(int, int)
getMousePosition
public Point getMousePosition(boolean allowChildren) throws HeadlessException
Returns the position of the mouse pointer in this Container
's coordinate space if the Container
is under the mouse pointer, otherwise returns null
. This method is similar to Component.getMousePosition()
with the exception that it can take the Container
's children into account. If allowChildren
is false
, this method will return a non-null value only if the mouse pointer is above the Container
directly, not above the part obscured by children. If allowChildren
is true
, this method returns a non-null value if the mouse pointer is above Container
or any of its descendants.
- Parameters:
-
allowChildren
- true if children should be taken into account - Returns:
- mouse coordinates relative to this
Component
, or null - Throws:
-
HeadlessException
- if GraphicsEnvironment.isHeadless() returns true - Since:
- 1.5
- See Also:
Component.getMousePosition()
findComponentAt
public Component findComponentAt(int x, int y)
Locates the visible child component that contains the specified position. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.
The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.
- Parameters:
-
x
- the x coordinate -
y
- the y coordinate - Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
- Since:
- 1.2
- See Also:
-
Component.contains(int, int)
,getComponentAt(int, int)
findComponentAt
public Component findComponentAt(Point p)
Locates the visible child component that contains the specified point. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.
The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.
- Parameters:
-
p
- the point. - Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
- Throws:
-
NullPointerException
- ifp
isnull
- Since:
- 1.2
- See Also:
-
Component.contains(int, int)
,getComponentAt(int, int)
addNotify
public void addNotify()
Makes this Container displayable by connecting it to a native screen resource. Making a container displayable will cause all of its children to be made displayable. This method is called internally by the toolkit and should not be called directly by programs.
- Overrides:
-
addNotify
in classComponent
- See Also:
-
Component.isDisplayable()
,removeNotify()
removeNotify
public void removeNotify()
Makes this Container undisplayable by removing its connection to its native screen resource. Making a container undisplayable will cause all of its children to be made undisplayable. This method is called by the toolkit internally and should not be called directly by programs.
- Overrides:
-
removeNotify
in classComponent
- See Also:
-
Component.isDisplayable()
,addNotify()
isAncestorOf
public boolean isAncestorOf(Component c)
Checks if the component is contained in the component hierarchy of this container.
- Parameters:
-
c
- the component - Returns:
-
true
if it is an ancestor;false
otherwise. - Since:
- 1.1
paramString
protected String paramString()
Returns a string representing the state of this Container
. 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
.
- Overrides:
-
paramString
in classComponent
- Returns:
- the parameter string of this container
list
public void list(PrintStream out, int indent)
Prints a listing of this container to the specified output stream. The listing starts at the specified indentation.
The immediate children of the container are printed with an indentation of indent+1
. The children of those children are printed at indent+2
and so on.
- Overrides:
-
list
in classComponent
- Parameters:
-
out
- a print stream -
indent
- the number of spaces to indent - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.0
- See Also:
Component.list(java.io.PrintStream, int)
list
public void list(PrintWriter out, int indent)
Prints out a list, starting at the specified indentation, to the specified print writer.
The immediate children of the container are printed with an indentation of indent+1
. The children of those children are printed at indent+2
and so on.
- Overrides:
-
list
in classComponent
- Parameters:
-
out
- a print writer -
indent
- the number of spaces to indent - Throws:
-
NullPointerException
- ifout
isnull
- Since:
- 1.1
- See Also:
Component.list(java.io.PrintWriter, int)
setFocusTraversalKeys
public void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
Sets the focus traversal keys for a given traversal operation for this Container.
The default values for a Container'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 |
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS | Go down 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 Container. 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 Container inherits the Set from its parent. If all ancestors of this Container 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
.
- Overrides:
-
setFocusTraversalKeys
in classComponent
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_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, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_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 Container - Since:
- 1.4
- See Also:
-
getFocusTraversalKeys(int)
,KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
,KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
getFocusTraversalKeys
public Set<AWTKeyStroke> getFocusTraversalKeys(int id)
Returns the Set of focus traversal keys for a given traversal operation for this Container. (See setFocusTraversalKeys
for a full description of each key.)
If a Set of traversal keys has not been explicitly defined for this Container, then this Container's parent's Set is returned. If no Set has been explicitly defined for any of this Container's ancestors, then the current KeyboardFocusManager's default Set is returned.
- Overrides:
-
getFocusTraversalKeys
in classComponent
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_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, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_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
,KeyboardFocusManager.DOWN_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 Container. If this method returns false
, this Container is inheriting the Set from an ancestor, or from the current KeyboardFocusManager.
- Overrides:
-
areFocusTraversalKeysSet
in classComponent
- Parameters:
-
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_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, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS - Since:
- 1.4
isFocusCycleRoot
public boolean isFocusCycleRoot(Container container)
Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle. Each focus traversal cycle has only a single focus cycle root and each Container which is not a focus cycle root 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. This method will return true
for both such Containers in this case.
- Overrides:
-
isFocusCycleRoot
in classComponent
- Parameters:
-
container
- the Container to be tested - Returns:
-
true
if the specified Container is a focus-cycle- root of this Container;false
otherwise - Since:
- 1.4
- See Also:
isFocusCycleRoot()
setFocusTraversalPolicy
public void setFocusTraversalPolicy(FocusTraversalPolicy policy)
Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root. If the argument is null, this Container inherits its policy from its focus- cycle-root ancestor. If the argument is non-null, this policy will be inherited by all focus-cycle-root children that have no keyboard- traversal policy of their own (as will, recursively, their focus-cycle- root children).
If this Container is not a focus cycle root, the policy will be remembered, but will not be used or inherited by this or any other Containers until this Container is made a focus cycle root.
- Parameters:
-
policy
- the new focus traversal policy for this Container - Since:
- 1.4
- See Also:
-
getFocusTraversalPolicy()
,setFocusCycleRoot(boolean)
,isFocusCycleRoot(java.awt.Container)
getFocusTraversalPolicy
public FocusTraversalPolicy getFocusTraversalPolicy()
Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root. If no traversal policy has been explicitly set for this Container, then this Container's focus-cycle-root ancestor's policy is returned.
- Returns:
- this Container's focus traversal policy, or null if this Container is not a focus cycle root.
- Since:
- 1.4
- See Also:
-
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,setFocusCycleRoot(boolean)
,isFocusCycleRoot(java.awt.Container)
isFocusTraversalPolicySet
public boolean isFocusTraversalPolicySet()
Returns whether the focus traversal policy has been explicitly set for this Container. If this method returns false
, this Container will inherit its focus traversal policy from an ancestor.
- Returns:
-
true
if the focus traversal policy has been explicitly set for this Container;false
otherwise. - Since:
- 1.4
setFocusCycleRoot
public void setFocusCycleRoot(boolean focusCycleRoot)
Sets whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.
The alternative way to specify the traversal order of this Container's children is to make this Container a focus traversal policy provider.
- Parameters:
-
focusCycleRoot
- indicates whether this Container is the root of a focus traversal cycle - Since:
- 1.4
- See Also:
-
isFocusCycleRoot()
,setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,getFocusTraversalPolicy()
,ContainerOrderFocusTraversalPolicy
,setFocusTraversalPolicyProvider(boolean)
isFocusCycleRoot
public boolean isFocusCycleRoot()
Returns whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.
- Returns:
- whether this Container is the root of a focus traversal cycle
- Since:
- 1.4
- See Also:
-
setFocusCycleRoot(boolean)
,setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,getFocusTraversalPolicy()
,ContainerOrderFocusTraversalPolicy
setFocusTraversalPolicyProvider
public final void setFocusTraversalPolicyProvider(boolean provider)
Sets whether this container will be used to provide focus traversal policy. Container with this property as true
will be used to acquire focus traversal policy instead of closest focus cycle root ancestor.
- Parameters:
-
provider
- indicates whether this container will be used to provide focus traversal policy - Since:
- 1.5
- See Also:
-
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,getFocusTraversalPolicy()
,isFocusTraversalPolicyProvider()
isFocusTraversalPolicyProvider
public final boolean isFocusTraversalPolicyProvider()
Returns whether this container provides focus traversal policy. If this property is set to true
then when keyboard focus manager searches container hierarchy for focus traversal policy and encounters this container before any other container with this property as true or focus cycle roots then its focus traversal policy will be used instead of focus cycle root's policy.
- Returns:
-
true
if this container provides focus traversal policy,false
otherwise - Since:
- 1.5
- See Also:
-
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,getFocusTraversalPolicy()
,setFocusCycleRoot(boolean)
,setFocusTraversalPolicyProvider(boolean)
transferFocusDownCycle
public void transferFocusDownCycle()
Transfers the focus down one focus traversal cycle. If this Container is a focus cycle root, then the focus owner is set to this Container's default Component to focus, and the current focus cycle root is set to this Container. If this Container is not a focus cycle root, then no focus traversal operation occurs.
- Since:
- 1.4
- See Also:
-
Component.requestFocus()
,isFocusCycleRoot(java.awt.Container)
,setFocusCycleRoot(boolean)
applyComponentOrientation
public void applyComponentOrientation(ComponentOrientation o)
Sets the ComponentOrientation
property of this container and all components contained within it.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Overrides:
-
applyComponentOrientation
in classComponent
- Parameters:
-
o
- the new component orientation of this container and the components contained within it. - Throws:
-
NullPointerException
- iforientation
is null. - Since:
- 1.4
- See Also:
-
Component.setComponentOrientation(java.awt.ComponentOrientation)
,Component.getComponentOrientation()
,invalidate()
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 Container's font ("font")
- this Container's background color ("background")
- this Container's foreground color ("foreground")
- this Container's focusability ("focusable")
- this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
- this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
- this Container's focus traversal policy ("focusTraversalPolicy")
- this Container's focus-cycle-root state ("focusCycleRoot")
If listener is null, no exception is thrown and no action is performed.
- Overrides:
-
addPropertyChangeListener
in classComponent
- Parameters:
-
listener
- the PropertyChangeListener to be added - See Also:
-
Component.removePropertyChangeListener(java.beans.PropertyChangeListener)
,addPropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)
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 defaults:
- this Container's font ("font")
- this Container's background color ("background")
- this Container's foreground color ("foreground")
- this Container's focusability ("focusable")
- this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
- this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
- this Container's focus traversal policy ("focusTraversalPolicy")
- this Container's focus-cycle-root state ("focusCycleRoot")
- this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
- this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
If listener is null, no exception is thrown and no action is performed.
- Overrides:
-
addPropertyChangeListener
in classComponent
- Parameters:
-
propertyName
- one of the property names listed above -
listener
- the PropertyChangeListener to be added - See Also:
-
addPropertyChangeListener(java.beans.PropertyChangeListener)
,Component.removePropertyChangeListener(java.beans.PropertyChangeListener)