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1 /*******************************************************************************
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2 * Copyright (c) 2006, 2007 IBM Corporation and others.
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3 * All rights reserved. This program and the accompanying materials
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4 * are made available under the terms of the Eclipse Public License v1.0
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5 * which accompanies this distribution, and is available at
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6 * http://www.eclipse.org/legal/epl-v10.html
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7 *
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8 * Contributors:
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9 * IBM Corporation - initial API and implementation
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10 * Brad Reynolds - bug 158687
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11 * Brad Reynolds - bug 164653, 147515
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12 *******************************************************************************/
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13
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14 module org.eclipse.core.databinding.observable.value.WritableValue;
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15
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16 import java.lang.all;
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17
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18 import org.eclipse.core.databinding.observable.Diffs;
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19 import org.eclipse.core.databinding.observable.Realm;
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20
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21 /**
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22 * Mutable (writable) implementation of {@link IObservableValue} that will maintain a value and fire
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23 * change events when the value changes.
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24 * <p>
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25 * This class is thread safe. All state accessing methods must be invoked from
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26 * the {@link Realm#isCurrent() current realm}. Methods for adding and removing
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27 * listeners may be invoked from any thread.
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28 * </p>
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29 * @since 1.0
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30 */
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31 public class WritableValue : AbstractObservableValue {
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32
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33 private final Object valueType;
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34
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35 /**
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36 * Constructs a new instance with the default realm, a <code>null</code>
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37 * value type, and a <code>null</code> value.
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38 */
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39 public this() {
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40 this(null, null);
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41 }
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42
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43 /**
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44 * Constructs a new instance with the default realm.
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45 *
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46 * @param initialValue
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47 * can be <code>null</code>
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48 * @param valueType
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49 * can be <code>null</code>
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50 */
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51 public this(Object initialValue, Object valueType) {
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52 this(Realm.getDefault(), initialValue, valueType);
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53 }
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54
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55 /**
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56 * Constructs a new instance with the provided <code>realm</code>, a
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57 * <code>null</code> value type, and a <code>null</code> initial value.
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58 *
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59 * @param realm
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60 */
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61 public this(Realm realm) {
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62 this(realm, null, null);
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63 }
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64
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65 /**
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66 * Constructs a new instance.
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67 *
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68 * @param realm
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69 * @param initialValue
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70 * can be <code>null</code>
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71 * @param valueType
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72 * can be <code>null</code>
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73 */
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74 public this(Realm realm, Object initialValue, Object valueType) {
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75 super(realm);
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76 this.valueType = valueType;
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77 this.value = initialValue;
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78 }
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79
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80 private Object value = null;
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81
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82 public Object doGetValue() {
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83 return value;
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84 }
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85
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86 /**
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87 * @param value
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88 * The value to set.
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89 */
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90 public void doSetValue(Object value) {
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91 bool changed = false;
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92
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93 if (this.value is null && value !is null) {
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94 changed = true;
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95 } else if (this.value !is null && !this.value.equals(value)) {
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96 changed = true;
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97 }
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98
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99 if (changed) {
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100 fireValueChange(Diffs.createValueDiff(this.value, this.value = value));
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101 }
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102 }
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103
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104 public Object getValueType() {
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105 return valueType;
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106 }
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107
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108 /**
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109 * @param elementType can be <code>null</code>
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110 * @return new instance with the default realm and a value of <code>null</code>
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111 */
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112 public static WritableValue withValueType(Object elementType) {
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113 return new WritableValue(Realm.getDefault(), null, elementType);
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114 }
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115 }
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