1 /*
2 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javafx.beans.property;
27
28 import javafx.beans.InvalidationListener;
29 import javafx.beans.Observable;
30 import javafx.beans.binding.BooleanBinding;
31 import javafx.beans.value.ChangeListener;
32 import javafx.beans.value.ObservableBooleanValue;
33 import javafx.beans.value.ObservableValue;
34
35 import com.sun.javafx.binding.ExpressionHelper;
36 import java.lang.ref.WeakReference;
37 import javafx.beans.WeakListener;
38
39 /**
40 * The class {@code BooleanPropertyBase} is the base class for a property
41 * wrapping a {@code boolean} value.
42 *
43 * It provides all the functionality required for a property except for the
44 * {@link #getBean()} and {@link #getName()} methods, which must be implemented
45 * by extending classes.
46 *
47 * @see BooleanProperty
48 * @since JavaFX 2.0
49 */
50 public abstract class BooleanPropertyBase extends BooleanProperty {
51
52 private boolean value;
53 private ObservableBooleanValue observable = null;
54 private InvalidationListener listener = null;
55 private boolean valid = true;
56 private ExpressionHelper<Boolean> helper = null;
57
58 /**
59 * The constructor of the {@code BooleanPropertyBase}.
60 */
61 public BooleanPropertyBase() {
62 }
63
64 /**
65 * The constructor of the {@code BooleanPropertyBase}.
66 *
67 * @param initialValue
68 * the initial value of the wrapped value
69 */
70 public BooleanPropertyBase(boolean initialValue) {
71 this.value = initialValue;
72 }
73
74 @Override
75 public void addListener(InvalidationListener listener) {
76 helper = ExpressionHelper.addListener(helper, this, listener);
77 }
78
79 @Override
80 public void removeListener(InvalidationListener listener) {
81 helper = ExpressionHelper.removeListener(helper, listener);
82 }
83
84 @Override
85 public void addListener(ChangeListener<? super Boolean> listener) {
86 helper = ExpressionHelper.addListener(helper, this, listener);
87 }
88
89 @Override
90 public void removeListener(ChangeListener<? super Boolean> listener) {
91 helper = ExpressionHelper.removeListener(helper, listener);
92 }
93
94 /**
95 * Sends notifications to all attached
96 * {@link javafx.beans.InvalidationListener InvalidationListeners} and
97 * {@link javafx.beans.value.ChangeListener ChangeListeners}.
98 *
99 * This method is called when the value is changed, either manually by
100 * calling {@link #set(boolean)} or in case of a bound property, if the
101 * binding becomes invalid.
102 */
103 protected void fireValueChangedEvent() {
104 ExpressionHelper.fireValueChangedEvent(helper);
105 }
106
107 private void markInvalid() {
108 if (valid) {
109 valid = false;
110 invalidated();
111 fireValueChangedEvent();
112 }
113 }
114
115 /**
116 * The method {@code invalidated()} can be overridden to receive
117 * invalidation notifications. This is the preferred option in
118 * {@code Objects} defining the property, because it requires less memory.
119 *
120 * The default implementation is empty.
121 */
122 protected void invalidated() {
123 }
124
125 /**
126 * {@inheritDoc}
127 */
128 @Override
129 public boolean get() {
130 valid = true;
131 return observable == null ? value : observable.get();
132 }
133
134 /**
135 * {@inheritDoc}
136 */
137 @Override
138 public void set(boolean newValue) {
139 if (isBound()) {
140 throw new java.lang.RuntimeException((getBean() != null && getName() != null ?
141 getBean().getClass().getSimpleName() + "." + getName() + " : ": "") + "A bound value cannot be set.");
142 }
143 if (value != newValue) {
144 value = newValue;
145 markInvalid();
146 }
147 }
148
149 /**
150 * {@inheritDoc}
151 */
152 @Override
153 public boolean isBound() {
154 return observable != null;
155 }
156
157 /**
158 * {@inheritDoc}
159 * Note:
160 */
161 @Override
162 public void bind(final ObservableValue<? extends Boolean> rawObservable) {
163 if (rawObservable == null) {
164 throw new NullPointerException("Cannot bind to null");
165 }
166
167 final ObservableBooleanValue newObservable = (rawObservable instanceof ObservableBooleanValue) ? (ObservableBooleanValue) rawObservable
168 : new ValueWrapper(rawObservable);
169
170 if (!newObservable.equals(observable)) {
171 unbind();
172 observable = newObservable;
173 if (listener == null) {
174 listener = new Listener(this);
175 }
176 observable.addListener(listener);
177 markInvalid();
178 }
179 }
180
181 /**
182 * {@inheritDoc}
183 */
184 @Override
185 public void unbind() {
186 if (observable != null) {
187 value = observable.get();
188 observable.removeListener(listener);
189 if (observable instanceof ValueWrapper) {
190 ((ValueWrapper)observable).dispose();
191 }
192 observable = null;
193 }
194 }
195
196 /**
197 * Returns a string representation of this {@code BooleanPropertyBase} object.
198 * @return a string representation of this {@code BooleanPropertyBase} object.
199 */
200 @Override
201 public String toString() {
202 final Object bean = getBean();
203 final String name = getName();
204 final StringBuilder result = new StringBuilder("BooleanProperty [");
205 if (bean != null) {
206 result.append("bean: ").append(bean).append(", ");
207 }
208 if ((name != null) && (!name.equals(""))) {
209 result.append("name: ").append(name).append(", ");
210 }
211 if (isBound()) {
212 result.append("bound, ");
213 if (valid) {
214 result.append("value: ").append(get());
215 } else {
216 result.append("invalid");
217 }
218 } else {
219 result.append("value: ").append(get());
220 }
221 result.append("]");
222 return result.toString();
223 }
224
225 private static class Listener implements InvalidationListener, WeakListener {
226
227 private final WeakReference<BooleanPropertyBase> wref;
228
229 public Listener(BooleanPropertyBase ref) {
230 this.wref = new WeakReference<>(ref);
231 }
232
233 @Override
234 public void invalidated(Observable observable) {
235 BooleanPropertyBase ref = wref.get();
236 if (ref == null) {
237 observable.removeListener(this);
238 } else {
239 ref.markInvalid();
240 }
241 }
242
243 @Override
244 public boolean wasGarbageCollected() {
245 return wref.get() == null;
246 }
247 }
248
249 private class ValueWrapper extends BooleanBinding {
250 private ObservableValue<? extends Boolean> observable;
251
252 public ValueWrapper(ObservableValue<? extends Boolean> observable) {
253 this.observable = observable;
254 bind(observable);
255 }
256
257 @Override
258 protected boolean computeValue() {
259 final Boolean value = observable.getValue();
260 return (value == null) ? false : value;
261 }
262
263 @Override
264 public void dispose() {
265 unbind(observable);
266 }
267 }
268 }