J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2007 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.awt.event; |
| 27 | |
| 28 | import java.awt.AWTEvent; |
| 29 | import java.awt.ItemSelectable; |
| 30 | |
| 31 | /** |
| 32 | * A semantic event which indicates that an item was selected or deselected. |
| 33 | * This high-level event is generated by an ItemSelectable object (such as a |
| 34 | * List) when an item is selected or deselected by the user. |
| 35 | * The event is passed to every <code>ItemListener</code> object which |
| 36 | * registered to receive such events using the component's |
| 37 | * <code>addItemListener</code> method. |
| 38 | * <P> |
| 39 | * The object that implements the <code>ItemListener</code> interface gets |
| 40 | * this <code>ItemEvent</code> when the event occurs. The listener is |
| 41 | * spared the details of processing individual mouse movements and mouse |
| 42 | * clicks, and can instead process a "meaningful" (semantic) event like |
| 43 | * "item selected" or "item deselected". |
| 44 | * |
| 45 | * @author Carl Quinn |
| 46 | * |
| 47 | * @see java.awt.ItemSelectable |
| 48 | * @see ItemListener |
| 49 | * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/itemlistener.html">Tutorial: Writing an Item Listener</a> |
| 50 | * |
| 51 | * @since 1.1 |
| 52 | */ |
| 53 | public class ItemEvent extends AWTEvent { |
| 54 | |
| 55 | /** |
| 56 | * The first number in the range of ids used for item events. |
| 57 | */ |
| 58 | public static final int ITEM_FIRST = 701; |
| 59 | |
| 60 | /** |
| 61 | * The last number in the range of ids used for item events. |
| 62 | */ |
| 63 | public static final int ITEM_LAST = 701; |
| 64 | |
| 65 | /** |
| 66 | * This event id indicates that an item's state changed. |
| 67 | */ |
| 68 | public static final int ITEM_STATE_CHANGED = ITEM_FIRST; //Event.LIST_SELECT |
| 69 | |
| 70 | /** |
| 71 | * This state-change value indicates that an item was selected. |
| 72 | */ |
| 73 | public static final int SELECTED = 1; |
| 74 | |
| 75 | /** |
| 76 | * This state-change-value indicates that a selected item was deselected. |
| 77 | */ |
| 78 | public static final int DESELECTED = 2; |
| 79 | |
| 80 | /** |
| 81 | * The item whose selection state has changed. |
| 82 | * |
| 83 | * @serial |
| 84 | * @see #getItem() |
| 85 | */ |
| 86 | Object item; |
| 87 | |
| 88 | /** |
| 89 | * <code>stateChange</code> indicates whether the <code>item</code> |
| 90 | * was selected or deselected. |
| 91 | * |
| 92 | * @serial |
| 93 | * @see #getStateChange() |
| 94 | */ |
| 95 | int stateChange; |
| 96 | |
| 97 | /* |
| 98 | * JDK 1.1 serialVersionUID |
| 99 | */ |
| 100 | private static final long serialVersionUID = -608708132447206933L; |
| 101 | |
| 102 | /** |
| 103 | * Constructs an <code>ItemEvent</code> object. |
| 104 | * <p>Note that passing in an invalid <code>id</code> results in |
| 105 | * unspecified behavior. This method throws an |
| 106 | * <code>IllegalArgumentException</code> if <code>source</code> |
| 107 | * is <code>null</code>. |
| 108 | * |
| 109 | * @param source the <code>ItemSelectable</code> object |
| 110 | * that originated the event |
| 111 | * @param id an integer that identifies the event type |
| 112 | * @param item an object -- the item affected by the event |
| 113 | * @param stateChange |
| 114 | * an integer that indicates whether the item was |
| 115 | * selected or deselected |
| 116 | * @throws IllegalArgumentException if <code>source</code> is null |
| 117 | */ |
| 118 | public ItemEvent(ItemSelectable source, int id, Object item, int stateChange) { |
| 119 | super(source, id); |
| 120 | this.item = item; |
| 121 | this.stateChange = stateChange; |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * Returns the originator of the event. |
| 126 | * |
| 127 | * @return the ItemSelectable object that originated the event. |
| 128 | */ |
| 129 | public ItemSelectable getItemSelectable() { |
| 130 | return (ItemSelectable)source; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * Returns the item affected by the event. |
| 135 | * |
| 136 | * @return the item (object) that was affected by the event |
| 137 | */ |
| 138 | public Object getItem() { |
| 139 | return item; |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * Returns the type of state change (selected or deselected). |
| 144 | * |
| 145 | * @return an integer that indicates whether the item was selected |
| 146 | * or deselected |
| 147 | * |
| 148 | * @see #SELECTED |
| 149 | * @see #DESELECTED |
| 150 | */ |
| 151 | public int getStateChange() { |
| 152 | return stateChange; |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Returns a parameter string identifying this item event. |
| 157 | * This method is useful for event-logging and for debugging. |
| 158 | * |
| 159 | * @return a string identifying the event and its attributes |
| 160 | */ |
| 161 | public String paramString() { |
| 162 | String typeStr; |
| 163 | switch(id) { |
| 164 | case ITEM_STATE_CHANGED: |
| 165 | typeStr = "ITEM_STATE_CHANGED"; |
| 166 | break; |
| 167 | default: |
| 168 | typeStr = "unknown type"; |
| 169 | } |
| 170 | |
| 171 | String stateStr; |
| 172 | switch(stateChange) { |
| 173 | case SELECTED: |
| 174 | stateStr = "SELECTED"; |
| 175 | break; |
| 176 | case DESELECTED: |
| 177 | stateStr = "DESELECTED"; |
| 178 | break; |
| 179 | default: |
| 180 | stateStr = "unknown type"; |
| 181 | } |
| 182 | return typeStr + ",item="+item + ",stateChange="+stateStr; |
| 183 | } |
| 184 | |
| 185 | } |