001/* ComponentEvent.java -- notification of events for components
002   Copyright (C) 1999, 2002, 2005, 2006  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.awt.event;
040
041import gnu.java.lang.CPStringBuilder;
042
043import java.awt.AWTEvent;
044import 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 */
059public 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