Class List

All Implemented Interfaces:
ImageObserver, ItemSelectable, MenuContainer, Serializable, Accessible 
public class List
extends Component
implements ItemSelectable, Accessible

The List component presents the user with a scrolling list of text items. The list can be set up so that the user can choose either one item or multiple items.

For example, the code . . . 

List lst = new List(4, false);
lst.add("Mercury");
lst.add("Venus");
lst.add("Earth");
lst.add("JavaSoft");
lst.add("Mars");
lst.add("Jupiter");
lst.add("Saturn");
lst.add("Uranus");
lst.add("Neptune");
lst.add("Pluto");
cnt.add(lst);

where cnt is a container, produces the following scrolling list:

Shows a list containing: Venus, Earth, JavaSoft, and Mars. Javasoft is selected.

If the List allows multiple selections, then clicking on an item that is already selected deselects it. In the preceding example, only one item from the scrolling list can be selected at a time, since the second argument when creating the new scrolling list is false. If the List does not allow multiple selections, selecting an item causes any other selected item to be deselected.

Note that the list in the example shown was created with four visible rows. Once the list has been created, the number of visible rows cannot be changed. A default List is created with four rows, so that lst = new List() is equivalent to list = new List(4, false).

Beginning with Java 1.1, the Abstract Window Toolkit sends the List object all mouse, keyboard, and focus events that occur over it. (The old AWT event model is being maintained only for backwards compatibility, and its use is discouraged.)

When an item is selected or deselected by the user, AWT sends an instance of ItemEvent to the list. When the user double-clicks on an item in a scrolling list, AWT sends an instance of ActionEvent to the list following the item event. AWT also generates an action event when the user presses the return key while an item in the list is selected.

If an application wants to perform some action based on an item in this list being selected or activated by the user, it should implement ItemListener or ActionListener as appropriate and register the new listener to receive events from this list.

For multiple-selection scrolling lists, it is considered a better user interface to use an external gesture (such as clicking on a button) to trigger the action.

Since:
1.0
See Also:
ItemEvent, ItemListener, ActionEvent, ActionListener, Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type Class Description
protected class  List.AccessibleAWTList

This class implements accessibility support for the List class.

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

Constructors
Constructor Description
List()

Creates a new scrolling list.
List​(int rows)

Creates a new scrolling list initialized with the specified number of visible lines.
List​(int rows, boolean multipleMode)

Creates a new scrolling list initialized to display the specified number of rows.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type Method Description
void add​(String item)

Adds the specified item to the end of scrolling list.
void add​(String item, int index)

Adds the specified item to the scrolling list at the position indicated by the index.
void addActionListener​(ActionListener l)

Adds the specified action listener to receive action events from this list.
void addItem​(String item)

Deprecated.

replaced by add(String).
void addItem​(String item, int index)

Deprecated.

replaced by add(String, int).
void addItemListener​(ItemListener l)

Adds the specified item listener to receive item events from this list.
void addNotify()

Creates the peer for the list.
boolean allowsMultipleSelections()

Deprecated.

As of JDK version 1.1, replaced by isMultipleMode().
void clear()

Deprecated.

As of JDK version 1.1, replaced by removeAll().
int countItems()

Deprecated.

As of JDK version 1.1, replaced by getItemCount().
void delItem​(int position)

Deprecated.

replaced by remove(String) and remove(int).
void delItems​(int start, int end)

Deprecated.

As of JDK version 1.1, Not for public use in the future.
void deselect​(int index)

Deselects the item at the specified index.
AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this List.
ActionListener[] getActionListeners()

Returns an array of all the action listeners registered on this list.
String getItem​(int index)

Gets the item associated with the specified index.
int getItemCount()

Gets the number of items in the list.
ItemListener[] getItemListeners()

Returns an array of all the item listeners registered on this list.
String[] getItems()

Gets the items in the list.
<T extends EventListener>
T[]		 getListeners​(Class<T> listenerType)

Returns an array of all the objects currently registered as FooListeners upon this List.
Dimension getMinimumSize()

Determines the minimum size of this scrolling list.
Dimension getMinimumSize​(int rows)

Gets the minimum dimensions for a list with the specified number of rows.
Dimension getPreferredSize()

Gets the preferred size of this scrolling list.
Dimension getPreferredSize​(int rows)

Gets the preferred dimensions for a list with the specified number of rows.
int getRows()

Gets the number of visible lines in this list.
int getSelectedIndex()

Gets the index of the selected item on the list,
int[] getSelectedIndexes()

Gets the selected indexes on the list.
String getSelectedItem()

Gets the selected item on this scrolling list.
String[] getSelectedItems()

Gets the selected items on this scrolling list.
Object[] getSelectedObjects()

Gets the selected items on this scrolling list in an array of Objects.
int getVisibleIndex()

Gets the index of the item that was last made visible by the method makeVisible.
boolean isIndexSelected​(int index)

Determines if the specified item in this scrolling list is selected.
boolean isMultipleMode()

Determines whether this list allows multiple selections.
boolean isSelected​(int index)

Deprecated.

As of JDK version 1.1, replaced by isIndexSelected(int).
void makeVisible​(int index)

Makes the item at the specified index visible.
Dimension minimumSize()

Deprecated.

As of JDK version 1.1, replaced by getMinimumSize().
Dimension minimumSize​(int rows)

Deprecated.

As of JDK version 1.1, replaced by getMinimumSize(int).
protected String paramString()

Returns the parameter string representing the state of this scrolling list.
Dimension preferredSize()

Deprecated.

As of JDK version 1.1, replaced by getPreferredSize().
Dimension preferredSize​(int rows)

Deprecated.

As of JDK version 1.1, replaced by getPreferredSize(int).
protected void processActionEvent​(ActionEvent e)

Processes action events occurring on this component by dispatching them to any registered ActionListener objects.
protected void processEvent​(AWTEvent e)

Processes events on this scrolling list.
protected void processItemEvent​(ItemEvent e)

Processes item events occurring on this list by dispatching them to any registered ItemListener objects.
void remove​(int position)

Removes the item at the specified position from this scrolling list.
void remove​(String item)

Removes the first occurrence of an item from the list.
void removeActionListener​(ActionListener l)

Removes the specified action listener so that it no longer receives action events from this list.
void removeAll()

Removes all items from this list.
void removeItemListener​(ItemListener l)

Removes the specified item listener so that it no longer receives item events from this list.
void removeNotify()

Removes the peer for this list.
void replaceItem​(String newValue, int index)

Replaces the item at the specified index in the scrolling list with the new string.
void select​(int index)

Selects the item at the specified index in the scrolling list.
void setMultipleMode​(boolean b)

Sets the flag that determines whether this list allows multiple selections.
void setMultipleSelections​(boolean b)

Deprecated.

As of JDK version 1.1, replaced by setMultipleMode(boolean).

Methods declared in class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, prepareImage, prepareImage, print, 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, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

List

public List()
     throws HeadlessException

Creates a new scrolling list. By default, there are four visible lines and multiple selections are not allowed. Note that this is a convenience method for List(0, false). Also note that the number of visible lines in the list cannot be changed after it has been created.

Throws:
HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
See Also:
GraphicsEnvironment.isHeadless()

List

public List​(int rows)
     throws HeadlessException

Creates a new scrolling list initialized with the specified number of visible lines. By default, multiple selections are not allowed. Note that this is a convenience method for List(rows, false). Also note that the number of visible rows in the list cannot be changed after it has been created.

Parameters:
rows - the number of items to show.
Throws:
HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
Since:
1.1
See Also:
GraphicsEnvironment.isHeadless()

List

public List​(int rows,
            boolean multipleMode)
     throws HeadlessException

Creates a new scrolling list initialized to display the specified number of rows. Note that if zero rows are specified, then the list will be created with a default of four rows. Also note that the number of visible rows in the list cannot be changed after it has been created. If the value of multipleMode is true, then the user can select multiple items from the list. If it is false, only one item at a time can be selected.

Parameters:
rows - the number of items to show.
multipleMode - if true, then multiple selections are allowed; otherwise, only one item can be selected at a time.
Throws:
HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
See Also:
GraphicsEnvironment.isHeadless()

Method Detail

addNotify

public void addNotify()

Creates the peer for the list. The peer allows us to modify the list's appearance without changing its functionality.

Overrides:
addNotify in class Component
See Also:
Component.isDisplayable(), Component.removeNotify(), Component.invalidate()

removeNotify

public void removeNotify()

Removes the peer for this list. The peer allows us to modify the list's appearance without changing its functionality.

Overrides:
removeNotify in class Component
See Also:
Component.isDisplayable(), Component.addNotify()

getItemCount

public int getItemCount()

Gets the number of items in the list.

Returns:
the number of items in the list
Since:
1.1
See Also:
getItem(int)

countItems

@Deprecated
public int countItems()
Deprecated.
As of JDK version 1.1, replaced by getItemCount().

Returns the number of items in the list.

Returns:
the number of items in the list

getItem

public String getItem​(int index)

Gets the item associated with the specified index.

Parameters:
index - the position of the item
Returns:
an item that is associated with the specified index
See Also:
getItemCount()

getItems

public String[] getItems()

Gets the items in the list.

Returns:
a string array containing items of the list
Since:
1.1
See Also:
select(int), deselect(int), isIndexSelected(int)

add

public void add​(String item)

Adds the specified item to the end of scrolling list.

Parameters:
item - the item to be added
Since:
1.1

addItem

@Deprecated
public void addItem​(String item)
Deprecated.
replaced by add(String).

Adds the specified item to the end of the list.

Parameters:
item - the item to be added

add

public void add​(String item,
                int index)

Adds the specified item to the scrolling list at the position indicated by the index. The index is zero-based. If the value of the index is less than zero, or if the value of the index is greater than or equal to the number of items in the list, then the item is added to the end of the list.

Parameters:
item - the item to be added; if this parameter is null then the item is treated as an empty string, ""
index - the position at which to add the item
Since:
1.1

addItem

@Deprecated
public void addItem​(String item,
                    int index)
Deprecated.
replaced by add(String, int).

Adds the specified item to the list at the position indicated by the index.

Parameters:
item - the item to be added
index - the position at which to add the item

replaceItem

public void replaceItem​(String newValue,
                        int index)

Replaces the item at the specified index in the scrolling list with the new string.

Parameters:
newValue - a new string to replace an existing item
index - the position of the item to replace
Throws:
ArrayIndexOutOfBoundsException - if index is out of range

removeAll

public void removeAll()

Removes all items from this list.

Since:
1.1
See Also:
remove(java.lang.String), delItems(int, int)

clear

@Deprecated
public void clear()
Deprecated.
As of JDK version 1.1, replaced by removeAll().

remove

public void remove​(String item)

Removes the first occurrence of an item from the list. If the specified item is selected, and is the only selected item in the list, the list is set to have no selection.

Parameters:
item - the item to remove from the list
Throws:
IllegalArgumentException - if the item doesn't exist in the list
Since:
1.1

remove

public void remove​(int position)

Removes the item at the specified position from this scrolling list. If the item with the specified position is selected, and is the only selected item in the list, the list is set to have no selection.

Parameters:
position - the index of the item to delete
Throws:
ArrayIndexOutOfBoundsException - if the position is less than 0 or greater than getItemCount()-1
Since:
1.1
See Also:
add(String, int)

delItem

@Deprecated
public void delItem​(int position)
Deprecated.
replaced by remove(String) and remove(int).

Removes the item at the specified position.

Parameters:
position - the index of the item to delete

getSelectedIndex

public int getSelectedIndex()

Gets the index of the selected item on the list,

Returns:
the index of the selected item; if no item is selected, or if multiple items are selected, -1 is returned.
See Also:
select(int), deselect(int), isIndexSelected(int)

getSelectedIndexes

public int[] getSelectedIndexes()

Gets the selected indexes on the list.

Returns:
an array of the selected indexes on this scrolling list; if no item is selected, a zero-length array is returned.
See Also:
select(int), deselect(int), isIndexSelected(int)

getSelectedItem

public String getSelectedItem()

Gets the selected item on this scrolling list.

Returns:
the selected item on the list; if no item is selected, or if multiple items are selected, null is returned.
See Also:
select(int), deselect(int), isIndexSelected(int)

getSelectedItems

public String[] getSelectedItems()

Gets the selected items on this scrolling list.

Returns:
an array of the selected items on this scrolling list; if no item is selected, a zero-length array is returned.
See Also:
select(int), deselect(int), isIndexSelected(int)

getSelectedObjects

public Object[] getSelectedObjects()

Gets the selected items on this scrolling list in an array of Objects.

Specified by:
getSelectedObjects in interface ItemSelectable
Returns:
an array of Objects representing the selected items on this scrolling list; if no item is selected, a zero-length array is returned.
See Also:
getSelectedItems(), ItemSelectable

select

public void select​(int index)

Selects the item at the specified index in the scrolling list.

Note that passing out of range parameters is invalid, and will result in unspecified behavior.

Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent. The only way to trigger an ItemEvent is by user interaction.

Parameters:
index - the position of the item to select
See Also:
getSelectedItem(), deselect(int), isIndexSelected(int)

deselect

public void deselect​(int index)

Deselects the item at the specified index.

Note that passing out of range parameters is invalid, and will result in unspecified behavior.

If the item at the specified index is not selected, then the operation is ignored.

Parameters:
index - the position of the item to deselect
See Also:
select(int), getSelectedItem(), isIndexSelected(int)

isIndexSelected

public boolean isIndexSelected​(int index)

Determines if the specified item in this scrolling list is selected.

Parameters:
index - the item to be checked
Returns:
true if the specified item has been selected; false otherwise
Since:
1.1
See Also:
select(int), deselect(int)

isSelected

@Deprecated
public boolean isSelected​(int index)
Deprecated.
As of JDK version 1.1, replaced by isIndexSelected(int).

Determines if the specified item in the list is selected.

Parameters:
index - specifies the item to be checked
Returns:
true if the item is selected; otherwise false

getRows

public int getRows()

Gets the number of visible lines in this list. Note that once the List has been created, this number will never change.

Returns:
the number of visible lines in this scrolling list

isMultipleMode

public boolean isMultipleMode()

Determines whether this list allows multiple selections.

Returns:
true if this list allows multiple selections; otherwise, false
Since:
1.1
See Also:
setMultipleMode(boolean)

allowsMultipleSelections

@Deprecated
public boolean allowsMultipleSelections()
Deprecated.
As of JDK version 1.1, replaced by isMultipleMode().

Determines whether this list allows multiple selections.

Returns:
true if this list allows multiple selections; otherwise false

setMultipleMode

public void setMultipleMode​(boolean b)

Sets the flag that determines whether this list allows multiple selections. When the selection mode is changed from multiple-selection to single-selection, the selected items change as follows: If a selected item has the location cursor, only that item will remain selected. If no selected item has the location cursor, all items will be deselected.

Parameters:
b - if true then multiple selections are allowed; otherwise, only one item from the list can be selected at once
Since:
1.1
See Also:
isMultipleMode()

setMultipleSelections

@Deprecated
public void setMultipleSelections​(boolean b)
Deprecated.
As of JDK version 1.1, replaced by setMultipleMode(boolean).

Enables or disables multiple selection mode for this list.

Parameters:
b - true to enable multiple mode, false otherwise

getVisibleIndex

public int getVisibleIndex()

Gets the index of the item that was last made visible by the method makeVisible.

Returns:
the index of the item that was last made visible
See Also:
makeVisible(int)

makeVisible

public void makeVisible​(int index)

Makes the item at the specified index visible.

Parameters:
index - the position of the item
See Also:
getVisibleIndex()

getPreferredSize

public Dimension getPreferredSize​(int rows)

Gets the preferred dimensions for a list with the specified number of rows.

Parameters:
rows - number of rows in the list
Returns:
the preferred dimensions for displaying this scrolling list given that the specified number of rows must be visible
Since:
1.1
See Also:
Component.getPreferredSize()

preferredSize

@Deprecated
public Dimension preferredSize​(int rows)
Deprecated.
As of JDK version 1.1, replaced by getPreferredSize(int).

Returns the preferred size of this component assuming it has the specified number of rows.

Parameters:
rows - the number of rows
Returns:
the preferred dimensions for displaying this list

getPreferredSize

public Dimension getPreferredSize()

Gets the preferred size of this scrolling list.

Overrides:
getPreferredSize in class Component
Returns:
the preferred dimensions for displaying this scrolling list
Since:
1.1
See Also:
Component.getPreferredSize()

preferredSize

@Deprecated
public Dimension preferredSize()
Deprecated.
As of JDK version 1.1, replaced by getPreferredSize().

Description copied from class: Component

Returns the component's preferred size.

Overrides:
preferredSize in class Component
Returns:
the component's preferred size

getMinimumSize

public Dimension getMinimumSize​(int rows)

Gets the minimum dimensions for a list with the specified number of rows.

Parameters:
rows - number of rows in the list
Returns:
the minimum dimensions for displaying this scrolling list given that the specified number of rows must be visible
Since:
1.1
See Also:
Component.getMinimumSize()

minimumSize

@Deprecated
public Dimension minimumSize​(int rows)
Deprecated.
As of JDK version 1.1, replaced by getMinimumSize(int).

Returns the minimum dimensions for the list with the specified number of rows.

Parameters:
rows - the number of rows in the list
Returns:
the minimum dimensions for displaying this list

getMinimumSize

public Dimension getMinimumSize()

Determines the minimum size of this scrolling list.

Overrides:
getMinimumSize in class Component
Returns:
the minimum dimensions needed to display this scrolling list
Since:
1.1
See Also:
Component.getMinimumSize()

minimumSize

@Deprecated
public Dimension minimumSize()
Deprecated.
As of JDK version 1.1, replaced by getMinimumSize().

Description copied from class: Component

Returns the minimum size of this component.

Overrides:
minimumSize in class Component
Returns:
the minimum size of this component

addItemListener

public void addItemListener​(ItemListener l)

Adds the specified item listener to receive item events from this list. Item events are sent in response to user input, but not in response to calls to select or deselect. 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.

Specified by:
addItemListener in interface ItemSelectable
Parameters:
l - the item listener
Since:
1.1
See Also:
removeItemListener(java.awt.event.ItemListener), getItemListeners(), select(int), deselect(int), ItemEvent, ItemListener

removeItemListener

public void removeItemListener​(ItemListener l)

Removes the specified item listener so that it no longer receives item events from this list. 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.

Specified by:
removeItemListener in interface ItemSelectable
Parameters:
l - the item listener
Since:
1.1
See Also:
addItemListener(java.awt.event.ItemListener), getItemListeners(), ItemEvent, ItemListener

getItemListeners

public ItemListener[] getItemListeners()

Returns an array of all the item listeners registered on this list.

Returns:
all of this list's ItemListeners or an empty array if no item listeners are currently registered
Since:
1.4
See Also:
addItemListener(java.awt.event.ItemListener), removeItemListener(java.awt.event.ItemListener), ItemEvent, ItemListener

addActionListener

public void addActionListener​(ActionListener l)

Adds the specified action listener to receive action events from this list. Action events occur when a user double-clicks on a list item or types Enter when the list has the keyboard 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 action listener
Since:
1.1
See Also:
removeActionListener(java.awt.event.ActionListener), getActionListeners(), ActionEvent, ActionListener

removeActionListener

public void removeActionListener​(ActionListener l)

Removes the specified action listener so that it no longer receives action events from this list. Action events occur when a user double-clicks on a list item. 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 action listener
Since:
1.1
See Also:
addActionListener(java.awt.event.ActionListener), getActionListeners(), ActionEvent, ActionListener

getActionListeners

public ActionListener[] getActionListeners()

Returns an array of all the action listeners registered on this list.

Returns:
all of this list's ActionListeners or an empty array if no action listeners are currently registered
Since:
1.4
See Also:
addActionListener(java.awt.event.ActionListener), removeActionListener(java.awt.event.ActionListener), ActionEvent, ActionListener

getListeners

public <T extends EventListener> T[] getListeners​(Class<T> listenerType)

Returns an array of all the objects currently registered as FooListeners upon this List. FooListeners 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 List l for its item listeners with the following code: 

ItemListener[] ils = (ItemListener[])(l.getListeners(ItemListener.class));
If no such listeners exist, this method returns an empty array.
Overrides:
getListeners in class Component
Type Parameters:
T - the type of the listeners
Parameters:
listenerType - the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener
Returns:
an array of all objects registered as FooListeners on this list, or an empty array if no such listeners have been added
Throws:
ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener
Since:
1.3
See Also:
getItemListeners()

processEvent

protected void processEvent​(AWTEvent e)

Processes events on this scrolling list. If an event is an instance of ItemEvent, it invokes the processItemEvent method. Else, if the event is an instance of ActionEvent, it invokes processActionEvent. If the event is not an item event or an action event, it invokes processEvent on the superclass.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

Overrides:
processEvent in class Component
Parameters:
e - the event
Since:
1.1
See Also:
ActionEvent, ItemEvent, processActionEvent(java.awt.event.ActionEvent), processItemEvent(java.awt.event.ItemEvent)

processItemEvent

protected void processItemEvent​(ItemEvent e)

Processes item events occurring on this list by dispatching them to any registered ItemListener objects.

This method is not called unless item events are enabled for this component. Item events are enabled when one of the following occurs:

  • An ItemListener object is registered via addItemListener.
  • Item 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 item event
Since:
1.1
See Also:
ItemEvent, ItemListener, addItemListener(java.awt.event.ItemListener), Component.enableEvents(long)

processActionEvent

protected void processActionEvent​(ActionEvent e)

Processes action events occurring on this component by dispatching them to any registered ActionListener objects.

This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:

  • An ActionListener object is registered via addActionListener.
  • Action 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 action event
Since:
1.1
See Also:
ActionEvent, ActionListener, addActionListener(java.awt.event.ActionListener), Component.enableEvents(long)

paramString

protected String paramString()

Returns the parameter string representing the state of this scrolling list. This string is useful for debugging.

Overrides:
paramString in class Component
Returns:
the parameter string of this scrolling list

delItems

@Deprecated
public void delItems​(int start,
                     int end)
Deprecated.
As of JDK version 1.1, Not for public use in the future. This method is expected to be retained only as a package private method.

Deletes the list items in the specified index range.

Parameters:
start - the beginning index of the range to delete
end - the ending index of the range to delete

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this List. For lists, the AccessibleContext takes the form of an AccessibleAWTList. A new AccessibleAWTList instance is created, if necessary.

Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class Component
Returns:
an AccessibleAWTList that serves as the AccessibleContext of this List
Since:
1.3