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Java > Open Source Codes > org > eclipse > jface > internal > databinding > internal > swt > ComboObservableValue


1 /*******************************************************************************
2  * Copyright (c) 2005, 2007 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  * Brad Reynolds - bug 164653
11  * Ashley Cambrell - bug 198904
12  *******************************************************************************/
13 package org.eclipse.jface.internal.databinding.internal.swt;
14
15 import org.eclipse.core.databinding.observable.Diffs;
16 import org.eclipse.jface.internal.databinding.provisional.swt.AbstractSWTObservableValue;
17 import org.eclipse.jface.util.Assert;
18 import org.eclipse.swt.events.ModifyEvent;
19 import org.eclipse.swt.events.ModifyListener;
20 import org.eclipse.swt.widgets.Combo;
21
22 /**
23  * @since 3.2
24  *
25  */
26 public class ComboObservableValue extends AbstractSWTObservableValue {
27
28     private final Combo combo;
29     private final String JavaDoc attribute;
30     private boolean updating = false;
31     private String JavaDoc currentValue;
32     private ModifyListener modifyListener;
33
34     /**
35      * @param combo
36      * @param attribute
37      */
38     public ComboObservableValue(Combo combo, String JavaDoc attribute) {
39         super(combo);
40         this.combo = combo;
41         this.attribute = attribute;
42         
43         if (attribute.equals(SWTProperties.SELECTION)
44                 || attribute.equals(SWTProperties.TEXT)) {
45             this.currentValue = combo.getText();
46             modifyListener = new ModifyListener() {
47
48                 public void modifyText(ModifyEvent e) {
49                     if (!updating) {
50                         String JavaDoc oldValue = currentValue;
51                         currentValue = ComboObservableValue.this.combo
52                                 .getText();
53                         fireValueChange(Diffs.createValueDiff(oldValue,
54                                 currentValue));
55                     }
56                 }
57             };
58             combo.addModifyListener(modifyListener);
59         } else
60             throw new IllegalArgumentException JavaDoc();
61     }
62
63     public void doSetValue(final Object JavaDoc value) {
64         String JavaDoc oldValue = combo.getText();
65         try {
66             updating = true;
67             if (attribute.equals(SWTProperties.TEXT)) {
68                 String JavaDoc stringValue = value != null ? value.toString() : ""; //$NON-NLS-1$
69 combo.setText(stringValue);
70             } else if (attribute.equals(SWTProperties.SELECTION)) {
71                 String JavaDoc items[] = combo.getItems();
72                 int index = -1;
73                 if (items != null && value != null) {
74                     for (int i = 0; i < items.length; i++) {
75                         if (value.equals(items[i])) {
76                             index = i;
77                             break;
78                         }
79                     }
80                     if (index == -1) {
81                         combo.setText((String JavaDoc) value);
82                     } else {
83                         combo.select(index); // -1 will not "unselect"
84 }
85                 }
86             }
87         } finally {
88             updating = false;
89         }
90         fireValueChange(Diffs.createValueDiff(oldValue, combo.getText()));
91     }
92
93     public Object JavaDoc doGetValue() {
94         if (attribute.equals(SWTProperties.TEXT))
95             return combo.getText();
96
97         Assert.isTrue(attribute.equals(SWTProperties.SELECTION),
98                 "unexpected attribute: " + attribute); //$NON-NLS-1$
99 // The problem with a ccombo, is that it changes the text and
100 // fires before it update its selection index
101 return combo.getText();
102     }
103
104     public Object JavaDoc getValueType() {
105         Assert.isTrue(attribute.equals(SWTProperties.TEXT)
106                 || attribute.equals(SWTProperties.SELECTION),
107                 "unexpected attribute: " + attribute); //$NON-NLS-1$
108 return String JavaDoc.class;
109     }
110
111     /**
112      * @return attribute being observed
113      */
114     public String JavaDoc getAttribute() {
115         return attribute;
116     }
117
118     /*
119      * (non-Javadoc)
120      *
121      * @see org.eclipse.core.databinding.observable.value.AbstractObservableValue#dispose()
122      */
123     public synchronized void dispose() {
124         super.dispose();
125
126         if (modifyListener != null && !combo.isDisposed()) {
127             combo.removeModifyListener(modifyListener);
128         }
129     }
130 }
131
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