001 /* ItemEvent.java -- event for item state changes 002 Copyright (C) 1999, 2002, 2005 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.awt.event; 040 041 import java.awt.AWTEvent; 042 import java.awt.ItemSelectable; 043 044 /** 045 * This event is generated when a selection item changes state. This is an 046 * abstraction that distills a large number of individual mouse or keyboard 047 * events into a simpler "item selected" and "item deselected" events. 048 * 049 * @author Aaron M. Renn (arenn@urbanophile.com) 050 * @see ItemSelectable 051 * @see ItemListener 052 * @since 1.1 053 * @status updated to 1.4 054 */ 055 public class ItemEvent extends AWTEvent 056 { 057 /** 058 * Compatible with JDK 1.1+. 059 */ 060 private static final long serialVersionUID = -608708132447206933L; 061 062 /** This is the first id in the event id range used by this class. */ 063 public static final int ITEM_FIRST = 701; 064 065 /** This is the last id in the event id range used by this class. */ 066 public static final int ITEM_LAST = 701; 067 068 /** This event id indicates a state change occurred. */ 069 public static final int ITEM_STATE_CHANGED = 701; 070 071 /** This type indicates that the item was selected. */ 072 public static final int SELECTED = 1; 073 074 /** This type indicates that the item was deselected. */ 075 public static final int DESELECTED = 2; 076 077 /** 078 * The item affected by this event. 079 * 080 * @serial the item of the selection 081 */ 082 private final Object item; 083 084 /** 085 * The state change direction, one of {@link #SELECTED} or 086 * {@link #DESELECTED}. 087 * 088 * @serial the selection state 089 */ 090 private final int stateChange; 091 092 /** 093 * Initializes a new instance of <code>ItemEvent</code> with the specified 094 * source, id, and state change constant. Note that an invalid id leads to 095 * unspecified results. 096 * 097 * @param source the source of the event 098 * @param id the event id 099 * @param item the item affected by the state change 100 * @param stateChange one of {@link #SELECTED} or {@link #DESELECTED} 101 */ 102 public ItemEvent(ItemSelectable source, int id, Object item, int stateChange) 103 { 104 super(source, id); 105 this.item = item; 106 this.stateChange = stateChange; 107 } 108 109 /** 110 * This method returns the event source as an <code>ItemSelectable</code>. 111 * 112 * @return the event source as an <code>ItemSelected</code> 113 * @throws ClassCastException if source is changed to a non-ItemSelectable 114 */ 115 public ItemSelectable getItemSelectable() 116 { 117 return (ItemSelectable) source; 118 } 119 120 /** 121 * Returns the item affected by this state change. 122 * 123 * @return the item affected by this state change 124 */ 125 public Object getItem() 126 { 127 return item; 128 } 129 130 /** 131 * Returns the type of state change, either {@link #SELECTED} or 132 * {@link #DESELECTED}. 133 * 134 * @return the type of state change 135 */ 136 public int getStateChange() 137 { 138 return stateChange; 139 } 140 141 /** 142 * Returns a string identifying this event. This is in the format: 143 * <code>"ITEM_STATE_CHANGED,item=" + item + ",stateChange=" 144 * + (getStateChange() == DESELECTED ? "DESELECTED" : "SELECTED")</code>. 145 * 146 * @return a string identifying this event 147 */ 148 public String paramString() 149 { 150 return (id == ITEM_STATE_CHANGED ? "ITEM_STATE_CHANGED,item=" 151 : "unknown type,item=") + item + ",stateChange=" 152 + (stateChange == SELECTED ? "SELECTED" 153 : stateChange == DESELECTED ? "DESELECTED" : "unknown type"); 154 } 155 } // class ItemEvent