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comparison org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/swt/DelayedObservableValue.d @ 78:0a55d2d5a946

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Added file for databinding
author Frank Benoit <benoit@tionex.de>
date Tue, 14 Apr 2009 11:35:29 +0200
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76:f05e6e8b2f2d 78:0a55d2d5a946
1 /*******************************************************************************
2 * Copyright (c) 2007 Matthew Hall 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 * Matthew Hall - initial API and implementation (bug 180746)
10 * Boris Bokowski, IBM - initial API and implementation
11 * Matthew Hall - bug 212223
12 * Will Horn - bug 215297
13 * Matthew Hall - bug 208332
14 ******************************************************************************/
15
16 module org.eclipse.jface.internal.databinding.swt.DelayedObservableValue;
17
18 import java.lang.all;
19
20 import org.eclipse.core.databinding.observable.Diffs;
21 import org.eclipse.core.databinding.observable.IStaleListener;
22 import org.eclipse.core.databinding.observable.ObservableTracker;
23 import org.eclipse.core.databinding.observable.StaleEvent;
24 import org.eclipse.core.databinding.observable.value.IObservableValue;
25 import org.eclipse.core.databinding.observable.value.IValueChangeListener;
26 import org.eclipse.core.databinding.observable.value.IVetoableValue;
27 import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
28 import org.eclipse.core.databinding.observable.value.ValueChangingEvent;
29 import org.eclipse.core.databinding.observable.value.ValueDiff;
30 import org.eclipse.jface.databinding.swt.ISWTObservableValue;
31 import org.eclipse.jface.internal.databinding.provisional.swt.AbstractSWTObservableValue;
32 import org.eclipse.jface.util.Util;
33 import org.eclipse.swt.SWT;
34 import org.eclipse.swt.widgets.Control;
35 import org.eclipse.swt.widgets.Event;
36 import org.eclipse.swt.widgets.Listener;
37 import org.eclipse.swt.widgets.Widget;
38
39 /**
40 * {@link IObservableValue} implementation that wraps any
41 * {@link ISWTObservableValue} and delays notification of value change events
42 * from the wrapped observable value until a certain time has passed since the
43 * last change event, or until a FocusOut event is received from the underlying
44 * widget (whichever happens earlier). This class helps to delay validation
45 * until the user stops typing. To notify about pending changes, a delayed
46 * observable value will fire a stale event when the wrapped observable value
47 * fires a change event, but this change is being delayed.
48 *
49 * Note that this class will not forward {@link ValueChangingEvent} events from
50 * a wrapped {@link IVetoableValue}.
51 *
52 * @since 1.2
53 */
54 public class DelayedObservableValue : AbstractSWTObservableValue {
55 class ValueUpdater : Runnable {
56 private final Object oldValue;
57
58 bool cancel = false;
59 bool running = false;
60
61 this(Object oldValue) {
62 this.oldValue = oldValue;
63 }
64
65 void cancel() {
66 cancel = true;
67 }
68
69 public void run() {
70 if (!cancel)
71 try {
72 running = true;
73 internalFireValueChange(oldValue);
74 } finally {
75 running = false;
76 }
77 }
78 }
79
80 private IStaleListener staleListener = new class() IStaleListener {
81 public void handleStale(StaleEvent staleEvent) {
82 if (!updating)
83 fireStale();
84 }
85 };
86
87 private IValueChangeListener valueChangeListener = new class() IValueChangeListener {
88 public void handleValueChange(ValueChangeEvent event) {
89 if (!updating)
90 makeDirty();
91 }
92 };
93
94 private Listener focusOutListener = new class() Listener {
95 public void handleEvent(Event event) {
96 // Force update on focus out
97 if (dirty)
98 internalFireValueChange(cachedValue);
99 }
100 };
101
102 private final int delay;
103 private ISWTObservableValue observable;
104 private Control control;
105
106 private bool dirty = true;
107 private Object cachedValue = null;
108
109 private bool updating = false;
110
111 private ValueUpdater updater = null;
112
113 /**
114 * Constructs a new instance bound to the given
115 * <code>ISWTObservableValue</code> and configured to fire change events
116 * once there have been no value changes in the observable for
117 * <code>delay</code> milliseconds.
118 *
119 * @param delayMillis
120 * @param observable
121 * @throws IllegalArgumentException
122 * if <code>updateEventType</code> is an incorrect type.
123 */
124 public this(int delayMillis,
125 ISWTObservableValue observable) {
126 super(observable.getRealm(), observable.getWidget());
127 this.delay = delayMillis;
128 this.observable = observable;
129
130 observable.addValueChangeListener(valueChangeListener);
131 observable.addStaleListener(staleListener);
132 Widget widget = observable.getWidget();
133 if (null !is cast(Control)widget) {
134 control = cast(Control) widget;
135 control.addListener(SWT.FocusOut, focusOutListener);
136 }
137
138 cachedValue = doGetValue();
139 }
140
141 protected Object doGetValue() {
142 if (dirty) {
143 cachedValue = observable.getValue();
144 dirty = false;
145
146 if (updater !is null && !updater.running) {
147 fireValueChange(Diffs.createValueDiff(updater.oldValue,
148 cachedValue));
149 cancelScheduledUpdate();
150 }
151 }
152 return cachedValue;
153 }
154
155 protected void doSetValue(Object value) {
156 updating = true;
157 try {
158 // Principle of least surprise: setValue overrides any pending
159 // update from observable.
160 dirty = false;
161 cancelScheduledUpdate();
162
163 Object oldValue = cachedValue;
164 observable.setValue(value);
165 // Bug 215297 - target observable could veto or override value
166 // passed to setValue(). Make sure we cache whatever is set.
167 cachedValue = observable.getValue();
168
169 if (!Util.equals(oldValue, cachedValue))
170 fireValueChange(Diffs.createValueDiff(oldValue, cachedValue));
171 } finally {
172 updating = false;
173 }
174 }
175
176 public bool isStale() {
177 ObservableTracker.getterCalled(this);
178 return (dirty && updater !is null) || observable.isStale();
179 }
180
181 /**
182 * Returns the type of the value from {@link #doGetValue()}, i.e.
183 * String.class
184 *
185 * @see org.eclipse.core.databinding.observable.value.IObservableValue#getValueType()
186 */
187 public Object getValueType() {
188 return observable.getValueType();
189 }
190
191 public void dispose() {
192 cancelScheduledUpdate();
193 if (observable !is null) {
194 observable.dispose();
195 observable.removeValueChangeListener(valueChangeListener);
196 observable.removeStaleListener(staleListener);
197 observable = null;
198 }
199 if (control !is null) {
200 control.removeListener(SWT.FocusOut, focusOutListener);
201 control = null;
202 }
203 super.dispose();
204 }
205
206 private void makeDirty() {
207 if (!dirty) {
208 dirty = true;
209 fireStale();
210 }
211 cancelScheduledUpdate(); // if any
212 scheduleUpdate();
213 }
214
215 private void cancelScheduledUpdate() {
216 if (updater !is null) {
217 updater.cancel();
218 updater = null;
219 }
220 }
221
222 private void scheduleUpdate() {
223 updater = new ValueUpdater(cachedValue);
224 observable.getWidget().getDisplay().timerExec(delay, updater);
225 }
226
227 private void internalFireValueChange(Object oldValue) {
228 cancelScheduledUpdate();
229 fireValueChange(new class(oldValue) ValueDiff {
230 Object oldValue_;
231 this(Object o){ oldValue_ = o; }
232 public Object getOldValue() {
233 return oldValue_;
234 }
235
236 public Object getNewValue() {
237 return getValue();
238 }
239 });
240 }
241 }