platform/platform-impl/src/com/intellij/openapi/wm/impl/HierarchyWatcher.java

   1 /*
   2  * Copyright 2000-2009 JetBrains s.r.o.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package com.intellij.openapi.wm.impl;
  17
  18 import java.awt.*;
  19 import java.awt.event.ContainerEvent;
  20 import java.awt.event.ContainerListener;
  21
  22 /**
  23  * @author Anton Katilin
  24  * @author Vladimir Kondratyev
  25  */
  26 public abstract class HierarchyWatcher implements ContainerListener{
  27   public final void componentAdded(final ContainerEvent e){
  28     install(e.getChild());
  29     hierarchyChanged(e);
  30   }
  31
  32   public final void componentRemoved(final ContainerEvent e){
  33     final Component removedChild=e.getChild();
  34     deinstall(removedChild);
  35     hierarchyChanged(e);
  36   }
  37
  38   private void install(final Component component){
  39     if(component instanceof Container){
  40       final Container container=(Container)component;
  41       final int componentCount=container.getComponentCount();
  42       for(int i=0;i<componentCount;i++){
  43         install(container.getComponent(i));
  44       }
  45       container.addContainerListener(this);
  46     }
  47   }
  48
  49   private void deinstall(final Component component){
  50     if(component instanceof Container){
  51       final Container container=(Container)component;
  52       final int componentCount=container.getComponentCount();
  53       for(int i=0;i<componentCount;i++){
  54         deinstall(container.getComponent(i));
  55       }
  56       container.removeContainerListener(this);
  57     }
  58   }
  59
  60   /**
  61    * Override this method to get notifications abot changes in component hierarchy.
  62    * <code>HierarchyWatcher</code> invokes this method each time one of the populated container changes.
  63    * @param e event which describes the changes.
  64    */
  65   protected abstract void hierarchyChanged(ContainerEvent e);
  66 }