BaseObservableMapping


1   /*******************************************************************************
2    * Copyright (c) 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   ******************************************************************************/
11  
12  package org.eclipse.jface.internal.databinding.provisional.observable.mapping;
13  
14  import java.util.ArrayList  ;
15  import java.util.Collection  ;
16  import java.util.HashSet  ;
17  
18  import org.eclipse.jface.internal.databinding.provisional.observable.AbstractObservable;
19  import org.eclipse.jface.internal.databinding.provisional.observable.IChangeListener;
20  
21  /**
22   * @since 3.2
23   *
24   */
25  public abstract class BaseObservableMapping extends AbstractObservable {
26  
27      /**
28       * Points to an instance of IChangeListener or a Collection of
29       * IMappingChangeListener
30       */
31      protected Object   mappingChangeListeners = null;
32  
33      public void addMappingChangeListener(IMappingChangeListener listener) {
34          if (mappingChangeListeners == null) {
35              boolean hadListeners = hasListeners();
36              mappingChangeListeners = listener;
37              if (!hadListeners) {
38                  firstListenerAdded();
39              }
40              return;
41          }
42      
43          Collection   listenerList;
44          if (mappingChangeListeners instanceof IMappingChangeListener) {
45              IChangeListener l = (IChangeListener) mappingChangeListeners;
46      
47              listenerList = new ArrayList  ();
48              listenerList.add(l);
49          } else {
50              listenerList = (Collection  ) mappingChangeListeners;
51          }
52      
53          if (listenerList.size() > 16) {
54              HashSet   listenerSet = new HashSet  ();
55              listenerSet.addAll(listenerList);
56              mappingChangeListeners = listenerList;
57          }
58      
59          listenerList.add(listener);
60      }
61  
62      public void removeMappingChangeListener(IMappingChangeListener listener) {
63          if (mappingChangeListeners == listener) {
64              mappingChangeListeners = null;
65              if (!hasListeners()) {
66                  lastListenerRemoved();
67              }
68              return;
69          }
70      
71          if (mappingChangeListeners instanceof Collection  ) {
72              Collection   listenerList = (Collection  ) mappingChangeListeners;
73              listenerList.remove(listener);
74              if (listenerList.size() == 0) {
75                  mappingChangeListeners = null;
76                  if (!hasListeners()) {
77                      lastListenerRemoved();
78                  }
79              }
80          }
81      }
82  
83      protected void fireMappingValueChange(MappingDiff diff) {
84          if (mappingChangeListeners == null) {
85              return;
86          }
87      
88          if (mappingChangeListeners instanceof IMappingChangeListener) {
89              ((IMappingChangeListener) mappingChangeListeners).handleMappingValueChange(this, diff);
90              return;
91          }
92      
93          Collection   changeListenerCollection = (Collection  ) mappingChangeListeners;
94      
95          IMappingChangeListener[] listeners = (IMappingChangeListener[]) (changeListenerCollection)
96                  .toArray(new IMappingChangeListener[changeListenerCollection.size()]);
97          for (int i = 0; i < listeners.length; i++) {
98              listeners[i].handleMappingValueChange(this, diff);
99          }
100     }
101 
102 }
103
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