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.DoubleBinding;
31 import javafx.beans.value.ChangeListener;
32 import javafx.beans.value.ObservableValue;
33
34 import com.sun.javafx.binding.ExpressionHelper;
35 import java.lang.ref.WeakReference;
36 import javafx.beans.WeakListener;
37 import javafx.beans.value.ObservableDoubleValue;
38 import javafx.beans.value.ObservableNumberValue;
39
40 /**
41 * The class {@code DoublePropertyBase} is the base class for a property
42 * wrapping a {@code double} value.
43 *
44 * It provides all the functionality required for a property except for the
45 * {@link #getBean()} and {@link #getName()} methods, which must be implemented
46 * by extending classes.
47 *
48 * @see DoubleProperty
49 *
50 *
51 * @since JavaFX 2.0
52 */
53 public abstract class DoublePropertyBase extends DoubleProperty {
54
55 private double value;
56 private ObservableDoubleValue observable = null;
57 private InvalidationListener listener = null;
58 private boolean valid = true;
59 private ExpressionHelper<Number> helper = null;
60
61 /**
62 * The constructor of the {@code DoublePropertyBase}.
63 */
64 public DoublePropertyBase() {
65 }
66
67 /**
68 * The constructor of the {@code DoublePropertyBase}.
69 *
70 * @param initialValue
71 * the initial value of the wrapped value
72 */
73 public DoublePropertyBase(double initialValue) {
74 this.value = initialValue;
75 }
76
77 @Override
78 public void addListener(InvalidationListener listener) {
79 helper = ExpressionHelper.addListener(helper, this, listener);
80 }
81
82 @Override
83 public void removeListener(InvalidationListener listener) {
84 helper = ExpressionHelper.removeListener(helper, listener);
85 }
86
87 @Override
88 public void addListener(ChangeListener<? super Number> listener) {
89 helper = ExpressionHelper.addListener(helper, this, listener);
90 }
91
92 @Override
93 public void removeListener(ChangeListener<? super Number> listener) {
94 helper = ExpressionHelper.removeListener(helper, listener);
95 }
96
97 /**
98 * Sends notifications to all attached
99 * {@link javafx.beans.InvalidationListener InvalidationListeners} and
100 * {@link javafx.beans.value.ChangeListener ChangeListeners}.
101 *
102 * This method is called when the value is changed, either manually by
103 * calling {@link #set(double)} or in case of a bound property, if the
104 * binding becomes invalid.
105 */
106 protected void fireValueChangedEvent() {
107 ExpressionHelper.fireValueChangedEvent(helper);
108 }
109
110 private void markInvalid() {
111 if (valid) {
112 valid = false;
113 invalidated();
114 fireValueChangedEvent();
115 }
116 }
117
118 /**
119 * The method {@code invalidated()} can be overridden to receive
120 * invalidation notifications. This is the preferred option in
121 * {@code Objects} defining the property, because it requires less memory.
122 *
123 * The default implementation is empty.
124 */
125 protected void invalidated() {
126 }
127
128 /**
129 * {@inheritDoc}
130 */
131 @Override
132 public double get() {
133 valid = true;
134 return observable == null ? value : observable.get();
135 }
136
137 /**
138 * {@inheritDoc}
139 */
140 @Override
141 public void set(double newValue) {
142 if (isBound()) {
143 throw new java.lang.RuntimeException((getBean() != null && getName() != null ?
144 getBean().getClass().getSimpleName() + "." + getName() + " : ": "") + "A bound value cannot be set.");
145 }
146 if (value != newValue) {
147 value = newValue;
148 markInvalid();
149 }
150 }
151
152 /**
153 * {@inheritDoc}
154 */
155 @Override
156 public boolean isBound() {
157 return observable != null;
158 }
159
160 /**
161 * {@inheritDoc}
162 */
163 @Override
164 public void bind(final ObservableValue<? extends Number> rawObservable) {
165 if (rawObservable == null) {
166 throw new NullPointerException("Cannot bind to null");
167 }
168
169 ObservableDoubleValue newObservable;
170 if (rawObservable instanceof ObservableDoubleValue) {
171 newObservable = (ObservableDoubleValue)rawObservable;
172 } else if (rawObservable instanceof ObservableNumberValue) {
173 final ObservableNumberValue numberValue = (ObservableNumberValue)rawObservable;
174 newObservable = new DoubleBinding() {
175 {
176 super.bind(rawObservable);
177 }
178
179 @Override
180 protected double computeValue() {
181 return numberValue.doubleValue();
182 }
183 };
184 } else {
185 newObservable = new DoubleBinding() {
186 {
187 super.bind(rawObservable);
188 }
189
190 @Override
191 protected double computeValue() {
192 final Number value = rawObservable.getValue();
193 return (value == null)? 0.0 : value.doubleValue();
194 }
195 };
196 }
197
198 if (!newObservable.equals(observable)) {
199 unbind();
200 observable = newObservable;
201 if (listener == null) {
202 listener = new Listener(this);
203 }
204 observable.addListener(listener);
205 markInvalid();
206 }
207 }
208
209 /**
210 * {@inheritDoc}
211 */
212 @Override
213 public void unbind() {
214 if (observable != null) {
215 value = observable.get();
216 observable.removeListener(listener);
217 observable = null;
218 }
219 }
220
221 /**
222 * Returns a string representation of this {@code DoublePropertyBase} object.
223 * @return a string representation of this {@code DoublePropertyBase} object.
224 */
225 @Override
226 public String toString() {
227 final Object bean = getBean();
228 final String name = getName();
229 final StringBuilder result = new StringBuilder("DoubleProperty [");
230 if (bean != null) {
231 result.append("bean: ").append(bean).append(", ");
232 }
233 if ((name != null) && (!name.equals(""))) {
234 result.append("name: ").append(name).append(", ");
235 }
236 if (isBound()) {
237 result.append("bound, ");
238 if (valid) {
239 result.append("value: ").append(get());
240 } else {
241 result.append("invalid");
242 }
243 } else {
244 result.append("value: ").append(get());
245 }
246 result.append("]");
247 return result.toString();
248 }
249
250 private static class Listener implements InvalidationListener, WeakListener {
251
252 private final WeakReference<DoublePropertyBase> wref;
253
254 public Listener(DoublePropertyBase ref) {
255 this.wref = new WeakReference<>(ref);
256 }
257
258 @Override
259 public void invalidated(Observable observable) {
260 DoublePropertyBase ref = wref.get();
261 if (ref == null) {
262 observable.removeListener(this);
263 } else {
264 ref.markInvalid();
265 }
266 }
267
268 @Override
269 public boolean wasGarbageCollected() {
270 return wref.get() == null;
271 }
272 }
273 }