001 /* ComponentEvent.java -- notification of events for components
002 Copyright (C) 1999, 2002, 2005, 2006 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 gnu.java.lang.CPStringBuilder;
042
043 import java.awt.AWTEvent;
044 import java.awt.Component;
045
046 /**
047 * This class is for events generated when a component is moved, resized,
048 * hidden, or shown. These events normally do not need to be handled by the
049 * application, since the AWT system automatically takes care of them. This
050 * is also the superclass for other events on components, but
051 * ComponentListeners ignore such subclasses.
052 *
053 * @author Aaron M. Renn (arenn@urbanophile.com)
054 * @see ComponentAdapter
055 * @see ComponentListener
056 * @since 1.1
057 * @status updated to 1.4
058 */
059 public class ComponentEvent extends AWTEvent
060 {
061 /**
062 * Compatible with JDK 1.1+.
063 */
064 private static final long serialVersionUID = 8101406823902992965L;
065
066 /** This is the first id in the range of ids used by this class. */
067 public static final int COMPONENT_FIRST = 100;
068
069 /** This is the last id in the range of ids used by this class. */
070 public static final int COMPONENT_LAST = 103;
071
072 /** This id indicates that a component was moved. */
073 public static final int COMPONENT_MOVED = 100;
074
075 /** This id indicates that a component was resized. */
076 public static final int COMPONENT_RESIZED = 101;
077
078 /** This id indicates that a component was shown. */
079 public static final int COMPONENT_SHOWN = 102;
080
081 /** This id indicates that a component was hidden. */
082 public static final int COMPONENT_HIDDEN = 103;
083
084 /**
085 * Initializes a new instance of <code>ComponentEvent</code> with the
086 * specified source and id. Note that an invalid id leads to unspecified
087 * results.
088 *
089 * @param source the source of the event
090 * @param id the event id
091 * @throws IllegalArgumentException if source is null
092 */
093 public ComponentEvent(Component source, int id)
094 {
095 super(source, id);
096 }
097
098 /**
099 * This method returns the event source as a <code>Component</code>. If the
100 * source has subsequently been modified to a non-Component, this returns
101 * null.
102 *
103 * @return the event source as a <code>Component</code>, or null
104 */
105 public Component getComponent()
106 {
107 return source instanceof Component ? (Component) source : null;
108 }
109
110 /**
111 * This method returns a string identifying this event. This is the field
112 * name of the id type, and for COMPONENT_MOVED or COMPONENT_RESIZED, the
113 * new bounding box of the component.
114 *
115 * @return a string identifying this event
116 */
117 public String paramString()
118 {
119 CPStringBuilder s = new CPStringBuilder();
120
121 // Unlike Sun, we don't throw NullPointerException or ClassCastException
122 // when source was illegally changed.
123 if (id == COMPONENT_MOVED)
124 s.append("COMPONENT_MOVED ");
125 else if (id == COMPONENT_RESIZED)
126 s.append("COMPONENT_RESIZED ");
127 else if (id == COMPONENT_SHOWN)
128 s.append("COMPONENT_SHOWN ");
129 else if (id == COMPONENT_HIDDEN)
130 s.append("COMPONENT_HIDDEN ");
131 else
132 return "unknown type";
133
134 s.append("(").append(getComponent().getX()).append(",")
135 .append(getComponent().getY()).append(" ")
136 .append(getComponent().getWidth()).append("x")
137 .append(getComponent().getHeight()).append(")");
138
139 return s.toString();
140 }
141
142 } // class ComponentEvent