Source for java.awt.event.HierarchyEvent

   1: /* HierarchyEvent.java -- generated for a change in hierarchy
   2:    Copyright (C) 2000, 2002 Free Software Foundation
   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 gnu.java.lang.CPStringBuilder;
  42: 
  43: import java.awt.AWTEvent;
  44: import java.awt.Component;
  45: import java.awt.Container;
  46: 
  47: /**
  48:  * This class represents an event generated for an ancestor component which
  49:  * may affect this component. These events normally do not need to be handled
  50:  * by the application, since the AWT system automatically takes care of them.
  51:  *
  52:  * <p>There are two types of hierarchy events. The first type is handled by
  53:  * HierarchyListener, and includes addition or removal of an ancestor, or
  54:  * an ancestor changing its on-screen status (visible and/or displayble). The
  55:  * second type is handled by HierarchyBoundsListener, and includes resizing
  56:  * or moving of an ancestor.
  57:  *
  58:  * @author Bryce McKinlay
  59:  * @see HierarchyListener
  60:  * @see HierarchyBoundsAdapter
  61:  * @see HierarchyBoundsListener
  62:  * @since 1.3
  63:  * @status updated to 1.4
  64:  */
  65: public class HierarchyEvent extends AWTEvent
  66: {
  67:   /**
  68:    * Compatible with JDK 1.3+.
  69:    */
  70:   private static final long serialVersionUID = -5337576970038043990L;
  71: 
  72:   /** This is the first id in the range of ids used by this class. */
  73:   public static final int HIERARCHY_FIRST = 1400;
  74: 
  75:   /** This id indicates that the hierarchy tree changed. */
  76:   public static final int HIERARCHY_CHANGED = 1400;
  77: 
  78:   /** This id indicates that an ancestor was moved. */
  79:   public static final int ANCESTOR_MOVED = 1401;
  80: 
  81:   /** This id indicates that an ancestor was resized. */
  82:   public static final int ANCESTOR_RESIZED = 1402;
  83: 
  84:   /** This is the last id in the range of ids used by this class. */
  85:   public static final int HIERARCHY_LAST = 1402;
  86: 
  87:   /** This indicates that the HIERARCHY_CHANGED is a changed parent. */
  88:   public static final int PARENT_CHANGED = 1;
  89: 
  90:   /**
  91:    * This indicates that the HIERARCHY_CHANGED is caused by a change in
  92:    * displayability.
  93:    *
  94:    * @see Component#isDisplayable()
  95:    * @see Component#addNotify()
  96:    * @see Component#removeNotify()
  97:    */
  98:   public static final int DISPLAYABILITY_CHANGED = 2;
  99: 
 100:   /**
 101:    * This indicates that the HIERARCHY_CHANGED is a changed visibility.
 102:    *
 103:    * @see Component#isShowing()
 104:    * @see Component#addNotify()
 105:    * @see Component#removeNotify()
 106:    * @see Component#show()
 107:    * @see Component#hide()
 108:    */
 109:   public static final int SHOWING_CHANGED = 4;
 110: 
 111:   /**
 112:    * The component at the top of the changed hierarchy.
 113:    *
 114:    * @serial the top component changed
 115:    */
 116:   private final Component changed;
 117: 
 118:   /**
 119:    * The parent of this component, either before or after the change depending
 120:    * on the type of change.
 121:    *
 122:    * @serial the parent component changed
 123:    */
 124:   private final Container changedParent;
 125: 
 126:   /**
 127:    * The bitmask of HIERARCHY_CHANGED event types.
 128:    *
 129:    * @serial the change flags
 130:    */
 131:   private final long changeFlags;
 132: 
 133:   /**
 134:    * Initializes a new instance of <code>HierarchyEvent</code> with the
 135:    * specified parameters. Note that an invalid id leads to unspecified
 136:    * results.
 137:    *
 138:    * @param source the component whose hierarchy changed
 139:    * @param id the event id
 140:    * @param changed the top component in the tree of changed hierarchy
 141:    * @param changedParent the updated parent of this object
 142:    * @throws IllegalArgumentException if source is null
 143:    */
 144:   public HierarchyEvent(Component source, int id, Component changed,
 145:                         Container changedParent)
 146:   {
 147:     this(source, id, changed, changedParent, 0);
 148:   }
 149: 
 150:   /**
 151:    * Initializes a new instance of <code>HierarchyEvent</code> with the
 152:    * specified parameters. Note that an invalid id leads to unspecified
 153:    * results.
 154:    *
 155:    * @param source the component whose hierarchy changed
 156:    * @param id the event id
 157:    * @param changed the top component in the tree of changed hierarchy
 158:    * @param changedParent the updated parent of this object
 159:    * @param changeFlags the bitmask of specific HIERARCHY_CHANGED events
 160:    * @throws IllegalArgumentException if source is null
 161:    */
 162:   public HierarchyEvent(Component source, int id, Component changed,
 163:                         Container changedParent, long changeFlags)
 164:   {
 165:     super(source, id);
 166:     this.changed = changed;
 167:     this.changedParent = changedParent;
 168:     this.changeFlags = changeFlags;
 169:   }
 170: 
 171:   /**
 172:    * This method returns the event source as a <code>Component</code>. If the
 173:    * source has subsequently been modified to a non-Component, this returns
 174:    * null.
 175:    *
 176:    * @return the event source as a <code>Component</code>, or null
 177:    */
 178:   public Component getComponent()
 179:   {
 180:     return source instanceof Component ? (Component) source : null;
 181:   }
 182: 
 183:   /**
 184:    * Returns the component at the top of the hierarchy which changed.
 185:    *
 186:    * @return the top changed component
 187:    */
 188:   public Component getChanged()
 189:   {
 190:     return changed;
 191:   }
 192: 
 193:   /**
 194:    * Returns the parent of the component listed in <code>getChanged()</code>.
 195:    * If the cause of this event was <code>Container.add</code>, this is the
 196:    * new parent; if the cause was <code>Container.remove</code>, this is the
 197:    * old parent; otherwise it is the unchanged parent.
 198:    *
 199:    * @return the parent container of the changed component
 200:    */
 201:   public Container getChangedParent()
 202:   {
 203:     return changedParent;
 204:   }
 205: 
 206:   /**
 207:    * If this is a HIERARCHY_CHANGED event, this returns a bitmask of the
 208:    * types of changes that took place.
 209:    *
 210:    * @return the bitwise or of hierarchy change types, or 0
 211:    * @see #PARENT_CHANGED
 212:    * @see #DISPLAYABILITY_CHANGED
 213:    * @see #SHOWING_CHANGED
 214:    */
 215:   public long getChangeFlags()
 216:   {
 217:     return changeFlags;
 218:   }
 219: 
 220:   /**
 221:    * This method returns a string identifying this event. This is the field
 222:    * name of the id type, followed by a parenthesized listing of the changed
 223:    * component and its parent container. In addition, if the type is
 224:    * HIERARCHY_CHANGED, the flags preceed the changed component, in the
 225:    * order PARENT_CHANGED, DISPLAYABILITY_CHANGED, and SHOWING_CHANGED.
 226:    *
 227:    * @return a string identifying this event
 228:    */
 229:   public String paramString()
 230:   {
 231:     CPStringBuilder r = new CPStringBuilder();
 232:     switch (id)
 233:       {
 234:       case HIERARCHY_CHANGED:
 235:         r.append("HIERARCHY_CHANGED (");
 236:         if ((changeFlags & PARENT_CHANGED) != 0)
 237:           r.append("PARENT_CHANGED,");
 238:         if ((changeFlags & DISPLAYABILITY_CHANGED) != 0)
 239:           r.append("DISPLAYABILITY_CHANGED,");
 240:         if ((changeFlags & SHOWING_CHANGED) != 0)
 241:           r.append("SHOWING_CHANGED,");
 242:         break;
 243:       case ANCESTOR_MOVED:
 244:         r.append("ANCESTOR_MOVED (");
 245:         break;
 246:       case ANCESTOR_RESIZED:
 247:         r.append("ANCESTOR_RESIZED (");
 248:         break;
 249:       default:
 250:         return "unknown type";
 251:       }
 252:     r.append(changed).append(',').append(changedParent).append(')');
 253:     return r.toString();
 254:   }
 255: } // class HierarchyEvent