Source for java.awt.event.ContainerEvent

   1: /* ContainerEvent.java -- components added/removed from a container
   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.Component;
  42: import java.awt.Container;
  43: 
  44: /**
  45:  * This event is generated when a component is added or removed from a
  46:  * container.  Applications do not ordinarily need to handle these events
  47:  * since the AWT system handles them internally.
  48:  *
  49:  * @author Aaron M. Renn (arenn@urbanophile.com)
  50:  * @see ContainerAdapter
  51:  * @see ContainerListener
  52:  * @since 1.1
  53:  * @status updated to 1.4
  54:  */
  55: public class ContainerEvent extends ComponentEvent
  56: {
  57:   /**
  58:    * Compatible with JDK 1.1+.
  59:    */
  60:   private static final long serialVersionUID = -4114942250539772041L;
  61: 
  62:   /** This is the first id in the id range used by this class. */
  63:   public static final int CONTAINER_FIRST = 300;
  64: 
  65:   /** This is the last id in the id range used by this class. */
  66:   public static final int CONTAINER_LAST = 301;
  67: 
  68:   /** This id indicates a component was added to the container. */
  69:   public static final int COMPONENT_ADDED = 300;
  70: 
  71:   /** This id indicates a component was removed from the container. */
  72:   public static final int COMPONENT_REMOVED = 301;
  73: 
  74:   /**
  75:    * The non-null child component that was added or removed.
  76:    *
  77:    * @serial the child component that changed
  78:    */
  79:   private final Component child;
  80: 
  81:   /**
  82:    * Initializes a new instance of <code>ContainerEvent</code> with the
  83:    * specified source and id.  Additionally, the affected child component
  84:    * is also passed as a parameter. Note that an invalid id leads to
  85:    * unspecified results.
  86:    *
  87:    * @param source the source container of the event
  88:    * @param id the event id
  89:    * @param child the child component affected by this event
  90:    * @throws IllegalArgumentException if source is null
  91:    */
  92:   public ContainerEvent(Component source, int id, Component child)
  93:   {
  94:     super(source, id);
  95:     this.child = child;
  96:   }
  97: 
  98:   /**
  99:    * Returns the source of this event as a <code>Container</code>.
 100:    *
 101:    * @return the source of the event
 102:    * @throws ClassCastException if the source is changed to a non-Container
 103:    */
 104:   public Container getContainer()
 105:   {
 106:     return (Container) source;
 107:   }
 108: 
 109:   /**
 110:    * This method returns the child object that was added or removed from
 111:    * the container.
 112:    *
 113:    * @return the child object added or removed
 114:    */
 115:   public Component getChild()
 116:   {
 117:     return child;
 118:   }
 119: 
 120:   /**
 121:    * This method returns a string identifying this event. It is formatted as:
 122:    * <code>(getID() == COMPONENT_ADDED ? "COMPONENT_ADDED"
 123:    * : "COMPONENT_REMOVED") + ",child=" + getChild().getName()</code>.
 124:    *
 125:    * @return a string identifying this event
 126:    */
 127:   public String paramString()
 128:   {
 129:     // Unlike Sun, we don't throw NullPointerException if child is illegally
 130:     // null.
 131:     return (id == COMPONENT_ADDED ? "COMPONENT_ADDED,child="
 132:             : id == COMPONENT_REMOVED ? "COMPONENT_REMOVED,child="
 133:             : "unknown type,child=") + (child == null ? "" : child.getName());
 134:   }
 135: } // class ContainerEvent