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ItemEvent.javaAPI DocJava SE 5 API5057Fri Aug 26 14:56:50 BST 2005java.awt.event

ItemEvent

public class ItemEvent extends AWTEvent
A semantic event which indicates that an item was selected or deselected. This high-level event is generated by an ItemSelectable object (such as a List) when an item is selected or deselected by the user. The event is passed to every ItemListener object which registered to receive such events using the component's addItemListener method.

The object that implements the ItemListener interface gets this ItemEvent when the event occurs. The listener is spared the details of processing individual mouse movements and mouse clicks, and can instead process a "meaningful" (semantic) event like "item selected" or "item deselected".

version
1.28 12/19/03
author
Carl Quinn
see
java.awt.ItemSelectable
see
ItemListener
see
Tutorial: Writing an Item Listener
see
Reference: The Java Class Libraries (update file)
since
1.1

Fields Summary
public static final int
ITEM_FIRST
The first number in the range of ids used for item events.
public static final int
ITEM_LAST
The last number in the range of ids used for item events.
public static final int
ITEM_STATE_CHANGED
This event id indicates that an item's state changed.
public static final int
SELECTED
This state-change value indicates that an item was selected.
public static final int
DESELECTED
This state-change-value indicates that a selected item was deselected.
Object
item
The item whose selection state has changed.
int
stateChange
stateChange indicates whether the item was selected or deselected.
private static final long
serialVersionUID
Constructors Summary
public ItemEvent(ItemSelectable source, int id, Object item, int stateChange)
Constructs an ItemEvent object.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.

param
source the ItemSelectable object that originated the event
param
id an integer that identifies the event type
param
item an object -- the item affected by the event
param
stateChange an integer that indicates whether the item was selected or deselected
throws
IllegalArgumentException if source is null


                                                                                                                                  
             
        super(source, id);
	this.item = item;
        this.stateChange = stateChange;
Methods Summary
public java.lang.ObjectgetItem()
Returns the item affected by the event.

return
the item (object) that was affected by the event

        return item;
public java.awt.ItemSelectablegetItemSelectable()
Returns the originator of the event.

return
the ItemSelectable object that originated the event.

        return (ItemSelectable)source;
public intgetStateChange()
Returns the type of state change (selected or deselected).

return
an integer that indicates whether the item was selected or deselected
see
#SELECTED
see
#DESELECTED

        return stateChange;
public java.lang.StringparamString()
Returns a parameter string identifying this item event. This method is useful for event-logging and for debugging.

return
a string identifying the event and its attributes

        String typeStr;
        switch(id) {
          case ITEM_STATE_CHANGED:
              typeStr = "ITEM_STATE_CHANGED";
              break;
          default:
              typeStr = "unknown type";
        }

        String stateStr;
        switch(stateChange) {
          case SELECTED:
              stateStr = "SELECTED";
              break;
          case DESELECTED:
              stateStr = "DESELECTED";
              break;
          default:
              stateStr = "unknown type";
        }
        return typeStr + ",item="+item + ",stateChange="+stateStr;