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