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Java > Open Source Codes > org > eclipse > jface > internal > databinding > internal > ListBinding


1 /*******************************************************************************
2  * Copyright (c) 2005, 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 package org.eclipse.jface.internal.databinding.internal;
12
13 import org.eclipse.jface.internal.databinding.provisional.BindSpec;
14 import org.eclipse.jface.internal.databinding.provisional.Binding;
15 import org.eclipse.jface.internal.databinding.provisional.BindingEvent;
16 import org.eclipse.jface.internal.databinding.provisional.DataBindingContext;
17 import org.eclipse.jface.internal.databinding.provisional.observable.list.IListChangeListener;
18 import org.eclipse.jface.internal.databinding.provisional.observable.list.IObservableList;
19 import org.eclipse.jface.internal.databinding.provisional.observable.list.ListDiff;
20 import org.eclipse.jface.internal.databinding.provisional.observable.list.ListDiffEntry;
21 import org.eclipse.jface.internal.databinding.provisional.observable.value.IObservableValue;
22 import org.eclipse.jface.internal.databinding.provisional.observable.value.WritableValue;
23 import org.eclipse.jface.internal.databinding.provisional.validation.ValidationError;
24
25 /**
26  *
27  *
28  */

29 public class ListBinding extends Binding {
30
31     private boolean updating = false;
32
33     private IObservableList modelList;
34
35     private final IObservableList targetList;
36
37     /**
38      * @param context
39      * @param targetList
40      * @param target
41      * @param modelList
42      * @param model
43      * @param bindSpec
44      */

45     public ListBinding(DataBindingContext context, IObservableList targetList,
46             IObservableList modelList, BindSpec bindSpec) {
47         super(context);
48         this.targetList = targetList;
49         this.modelList = modelList;
50         // TODO validation/conversion as specified by the bindSpec
51
targetList.addListChangeListener(targetChangeListener);
52         modelList.addListChangeListener(modelChangeListener);
53         updateTargetFromModel();
54     }
55
56     private final IListChangeListener targetChangeListener = new IListChangeListener() {
57         public void handleListChange(IObservableList source, ListDiff diff) {
58             if (updating) {
59                 return;
60             }
61             // TODO validation
62
BindingEvent e = new BindingEvent(modelList, targetList, diff,
63                     BindingEvent.EVENT_COPY_TO_MODEL,
64                     BindingEvent.PIPELINE_AFTER_GET);
65             if (failure(errMsg(fireBindingEvent(e)))) {
66                 return;
67             }
68             updating = true;
69             try {
70                 // get setDiff from event object - might have been modified by a
71
// listener
72
ListDiff setDiff = (ListDiff) e.diff;
73                 ListDiffEntry[] differences = setDiff.getDifferences();
74                 for (int i = 0; i < differences.length; i++) {
75                     ListDiffEntry entry = differences[i];
76                     if (entry.isAddition()) {
77                         modelList.add(entry.getPosition(), entry.getElement());
78                     } else {
79                         modelList.remove(entry.getPosition());
80                     }
81                 }
82                 e.pipelinePosition = BindingEvent.PIPELINE_AFTER_CHANGE;
83                 if (failure(errMsg(fireBindingEvent(e)))) {
84                     return;
85                 }
86             } finally {
87                 updating = false;
88             }
89         }
90     };
91
92     private IListChangeListener modelChangeListener = new IListChangeListener() {
93         public void handleListChange(IObservableList source, ListDiff diff) {
94             if (updating) {
95                 return;
96             }
97             // TODO validation
98
BindingEvent e = new BindingEvent(modelList, targetList, diff,
99                     BindingEvent.EVENT_COPY_TO_TARGET,
100                     BindingEvent.PIPELINE_AFTER_GET);
101             if (failure(errMsg(fireBindingEvent(e)))) {
102                 return;
103             }
104             updating = true;
105             try {
106                 // get setDiff from event object - might have been modified by a
107
// listener
108
ListDiff setDiff = (ListDiff) e.diff;
109                 ListDiffEntry[] differences = setDiff.getDifferences();
110                 for (int i = 0; i < differences.length; i++) {
111                     ListDiffEntry entry = differences[i];
112                     if (entry.isAddition()) {
113                         targetList.add(entry.getPosition(), entry.getElement());
114                     } else {
115                         targetList.remove(entry.getPosition());
116                     }
117                 }
118                 e.pipelinePosition = BindingEvent.PIPELINE_AFTER_CHANGE;
119                 if (failure(errMsg(fireBindingEvent(e)))) {
120                     return;
121                 }
122             } finally {
123                 updating = false;
124             }
125         }
126     };
127
128     private WritableValue partialValidationErrorObservable = new WritableValue(
129             null);
130
131     private WritableValue validationErrorObservable = new WritableValue(null);
132
133     private ValidationError errMsg(ValidationError validationError) {
134         partialValidationErrorObservable.setValue(null);
135         validationErrorObservable.setValue(validationError);
136         return validationError;
137     }
138
139     private boolean failure(ValidationError errorMessage) {
140         // FIXME: Need to fire a BindingEvent here
141
if (errorMessage != null
142                 && errorMessage.status == ValidationError.ERROR) {
143             return true;
144         }
145         return false;
146     }
147
148     public void updateTargetFromModel() {
149         updating = true;
150         try {
151             targetList.clear();
152             targetList.addAll(modelList);
153         } finally {
154             updating = false;
155         }
156     }
157
158     public IObservableValue getValidationError() {
159         return validationErrorObservable;
160     }
161
162     public IObservableValue getPartialValidationError() {
163         return partialValidationErrorObservable;
164     }
165
166     public void updateModelFromTarget() {
167         updating = true;
168         try {
169             modelList.clear();
170             modelList.addAll(targetList);
171         } finally {
172             updating = false;
173         }
174     }
175 }
176
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