1 /*
2 * Copyright (c) 2010, 2016, 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.binding;
27
28 import com.sun.javafx.binding.StringFormatter;
29 import javafx.beans.value.ObservableObjectValue;
30 import javafx.collections.FXCollections;
31 import javafx.collections.ObservableList;
32
33 import java.util.Locale;
34
35 /**
36 * {@code ObjectExpression} is an
37 * {@link javafx.beans.value.ObservableObjectValue} plus additional convenience
38 * methods to generate bindings in a fluent style.
39 * <p>
40 * A concrete sub-class of {@code ObjectExpression} has to implement the method
41 * {@link javafx.beans.value.ObservableObjectValue#get()}, which provides the
42 * actual value of this expression.
43 * @since JavaFX 2.0
44 */
45 public abstract class ObjectExpression<T> implements ObservableObjectValue<T> {
46
47 @Override
48 public T getValue() {
49 return get();
50 }
51
52 /**
53 * Returns an {@code ObjectExpression} that wraps an
54 * {@link javafx.beans.value.ObservableObjectValue}. If the
55 * {@code ObservableObjectValue} is already an {@code ObjectExpression}, it
56 * will be returned. Otherwise a new
57 * {@link javafx.beans.binding.ObjectBinding} is created that is bound to
58 * the {@code ObservableObjectValue}.
59 *
60 * @param <T> the type of the wrapped {@code Object}
61 * @param value
62 * The source {@code ObservableObjectValue}
63 * @return A {@code ObjectExpression} that wraps the
64 * {@code ObservableObjectValue} if necessary
65 * @throws NullPointerException
66 * if {@code value} is {@code null}
67 */
68 public static <T> ObjectExpression<T> objectExpression(
69 final ObservableObjectValue<T> value) {
70 if (value == null) {
71 throw new NullPointerException("Value must be specified.");
72 }
73 return value instanceof ObjectExpression ? (ObjectExpression<T>) value
74 : new ObjectBinding<T>() {
75 {
76 super.bind(value);
77 }
78
79 @Override
80 public void dispose() {
81 super.unbind(value);
82 }
83
84 @Override
85 protected T computeValue() {
86 return value.get();
87 }
88
89 @Override
90 public ObservableList<ObservableObjectValue<T>> getDependencies() {
91 return FXCollections.singletonObservableList(value);
92 }
93 };
94 }
95
96 /**
97 * Creates a new {@code BooleanExpression} that holds {@code true} if this and
98 * another {@link javafx.beans.value.ObservableObjectValue} are equal.
99 *
100 * @param other
101 * the other {@code ObservableObjectValue}
102 * @return the new {@code BooleanExpression}
103 * @throws NullPointerException
104 * if {@code other} is {@code null}
105 */
106 public BooleanBinding isEqualTo(final ObservableObjectValue<?> other) {
107 return Bindings.equal(this, other);
108 }
109
110 /**
111 * Creates a new {@code BooleanExpression} that holds {@code true} if this
112 * {@code ObjectExpression} is equal to a constant value.
113 *
114 * @param other
115 * the constant value
116 * @return the new {@code BooleanExpression}
117 */
118 public BooleanBinding isEqualTo(final Object other) {
119 return Bindings.equal(this, other);
120 }
121
122 /**
123 * Creates a new {@code BooleanExpression} that holds {@code true} if this and
124 * another {@link javafx.beans.value.ObservableObjectValue} are not equal.
125 *
126 * @param other
127 * the other {@code ObservableObjectValue}
128 * @return the new {@code BooleanExpression}
129 * @throws NullPointerException
130 * if {@code other} is {@code null}
131 */
132 public BooleanBinding isNotEqualTo(final ObservableObjectValue<?> other) {
133 return Bindings.notEqual(this, other);
134 }
135
136 /**
137 * Creates a new {@code BooleanExpression} that holds {@code true} if this
138 * {@code ObjectExpression} is not equal to a constant value.
139 *
140 * @param other
141 * the constant value
142 * @return the new {@code BooleanExpression}
143 */
144 public BooleanBinding isNotEqualTo(final Object other) {
145 return Bindings.notEqual(this, other);
146 }
147
148 /**
149 * Creates a new {@link BooleanBinding} that holds {@code true} if this
150 * {@code ObjectExpression} is {@code null}.
151 *
152 * @return the new {@code BooleanBinding}
153 */
154 public BooleanBinding isNull() {
155 return Bindings.isNull(this);
156 }
157
158 /**
159 * Creates a new {@link BooleanBinding} that holds {@code true} if this
160 * {@code ObjectExpression} is not {@code null}.
161 *
162 * @return the new {@code BooleanBinding}
163 */
164 public BooleanBinding isNotNull() {
165 return Bindings.isNotNull(this);
166 }
167
168 /**
169 * Creates a {@link javafx.beans.binding.StringBinding} that holds the value
170 * of this {@code ObjectExpression} turned into a {@code String}. If the
171 * value of this {@code ObjectExpression} changes, the value of the
172 * {@code StringBinding} will be updated automatically.
173 *
174 * @return the new {@code StringBinding}
175 * @since JavaFX 8.0
176 */
177 public StringBinding asString() {
178 return (StringBinding) StringFormatter.convert(this);
179 }
180
181 /**
182 * Creates a {@link javafx.beans.binding.StringBinding} that holds the value
183 * of the {@code ObjectExpression} turned into a {@code String}. If the
184 * value of this {@code ObjectExpression} changes, the value of the
185 * {@code StringBinding} will be updated automatically.
186 * <p>
187 * The result is formatted according to the formatting {@code String}. See
188 * {@code java.util.Formatter} for formatting rules.
189 *
190 * @param format
191 * the formatting {@code String}
192 * @return the new {@code StringBinding}
193 * @since JavaFX 8.0
194 */
195 public StringBinding asString(String format) {
196 return (StringBinding) Bindings.format(format, this);
197 }
198
199 /**
200 * Creates a {@link javafx.beans.binding.StringBinding} that holds the value
201 * of the {@code NumberExpression} turned into a {@code String}. If the
202 * value of this {@code NumberExpression} changes, the value of the
203 * {@code StringBinding} will be updated automatically.
204 * <p>
205 * The result is formatted according to the formatting {@code String} and
206 * the passed in {@code Locale}. See {@code java.util.Formatter} for
207 * formatting rules. See {@code java.util.Locale} for details on
208 * {@code Locale}.
209 *
210 * @param locale the Locale to be used
211 * @param format
212 * the formatting {@code String}
213 * @return the new {@code StringBinding}
214 * @since JavaFX 8.0
215 */
216 public StringBinding asString(Locale locale, String format) {
217 return (StringBinding) Bindings.format(locale, format, this);
218 }
219 }