Source for java.awt.event.ItemEvent

   1: /* ItemEvent.java -- event for item state changes
   2:    Copyright (C) 1999, 2002, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.awt.event;
  40: 
  41: import java.awt.AWTEvent;
  42: import java.awt.ItemSelectable;
  43: 
  44: /**
  45:  * This event is generated when a selection item changes state. This is an
  46:  * abstraction that distills a large number of individual mouse or keyboard
  47:  * events into a simpler "item selected" and "item deselected" events.
  48:  *
  49:  * @author Aaron M. Renn (arenn@urbanophile.com)
  50:  * @see ItemSelectable
  51:  * @see ItemListener
  52:  * @since 1.1
  53:  * @status updated to 1.4
  54:  */
  55: public class ItemEvent extends AWTEvent
  56: {
  57:   /**
  58:    * Compatible with JDK 1.1+.
  59:    */
  60:   private static final long serialVersionUID = -608708132447206933L;
  61: 
  62:   /** This is the first id in the event id range used by this class. */
  63:   public static final int ITEM_FIRST = 701;
  64: 
  65:   /** This is the last id in the event id range used by this class. */
  66:   public static final int ITEM_LAST = 701;
  67: 
  68:   /** This event id indicates a state change occurred. */
  69:   public static final int ITEM_STATE_CHANGED = 701;
  70: 
  71:   /** This type indicates that the item was selected. */
  72:   public static final int SELECTED = 1;
  73: 
  74:   /** This type indicates that the item was deselected. */
  75:   public static final int DESELECTED = 2;
  76: 
  77:   /**
  78:    * The item affected by this event.
  79:    *
  80:    * @serial the item of the selection
  81:    */
  82:   private final Object item;
  83: 
  84:   /**
  85:    * The state change direction, one of {@link #SELECTED} or
  86:    * {@link #DESELECTED}.
  87:    *
  88:    * @serial the selection state
  89:    */
  90:   private final int stateChange;
  91: 
  92:   /**
  93:    * Initializes a new instance of <code>ItemEvent</code> with the specified
  94:    * source, id, and state change constant. Note that an invalid id leads to
  95:    * unspecified results.
  96:    *
  97:    * @param source the source of the event
  98:    * @param id the event id
  99:    * @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