1 /*
2 * Copyright (c) 1996, 2007, 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 java.beans;
27
28 import java.beans;
29
30 /**
31 * This is a support class to help build property editors.
32 * <p>
33 * It can be used either as a base class or as a delagatee.
34 */
35
36 public class PropertyEditorSupport implements PropertyEditor {
37
38 /**
39 * Constructs a <code>PropertyEditorSupport</code> object.
40 *
41 * @since 1.5
42 */
43 public PropertyEditorSupport() {
44 setSource(this);
45 }
46
47 /**
48 * Constructs a <code>PropertyEditorSupport</code> object.
49 *
50 * @param source the source used for event firing
51 * @since 1.5
52 */
53 public PropertyEditorSupport(Object source) {
54 if (source == null) {
55 throw new NullPointerException();
56 }
57 setSource(source);
58 }
59
60 /**
61 * Returns the bean that is used as the
62 * source of events. If the source has not
63 * been explicitly set then this instance of
64 * <code>PropertyEditorSupport</code> is returned.
65 *
66 * @return the source object or this instance
67 * @since 1.5
68 */
69 public Object getSource() {
70 return source;
71 }
72
73 /**
74 * Sets the source bean.
75 * <p>
76 * The source bean is used as the source of events
77 * for the property changes. This source should be used for information
78 * purposes only and should not be modified by the PropertyEditor.
79 *
80 * @param source source object to be used for events
81 * @since 1.5
82 */
83 public void setSource(Object source) {
84 this.source = source;
85 }
86
87 /**
88 * Set (or change) the object that is to be edited.
89 *
90 * @param value The new target object to be edited. Note that this
91 * object should not be modified by the PropertyEditor, rather
92 * the PropertyEditor should create a new object to hold any
93 * modified value.
94 */
95 public void setValue(Object value) {
96 this.value = value;
97 firePropertyChange();
98 }
99
100 /**
101 * Gets the value of the property.
102 *
103 * @return The value of the property.
104 */
105 public Object getValue() {
106 return value;
107 }
108
109 //----------------------------------------------------------------------
110
111 /**
112 * Determines whether the class will honor the paintValue method.
113 *
114 * @return True if the class will honor the paintValue method.
115 */
116
117 public boolean isPaintable() {
118 return false;
119 }
120
121 /**
122 * Paint a representation of the value into a given area of screen
123 * real estate. Note that the propertyEditor is responsible for doing
124 * its own clipping so that it fits into the given rectangle.
125 * <p>
126 * If the PropertyEditor doesn't honor paint requests (see isPaintable)
127 * this method should be a silent noop.
128 *
129 * @param gfx Graphics object to paint into.
130 * @param box Rectangle within graphics object into which we should paint.
131 */
132 public void paintValue(java.awt.Graphics gfx, java.awt.Rectangle box) {
133 }
134
135 //----------------------------------------------------------------------
136
137 /**
138 * This method is intended for use when generating Java code to set
139 * the value of the property. It should return a fragment of Java code
140 * that can be used to initialize a variable with the current property
141 * value.
142 * <p>
143 * Example results are "2", "new Color(127,127,34)", "Color.orange", etc.
144 *
145 * @return A fragment of Java code representing an initializer for the
146 * current value.
147 */
148 public String getJavaInitializationString() {
149 return "???";
150 }
151
152 //----------------------------------------------------------------------
153
154 /**
155 * Gets the property value as a string suitable for presentation
156 * to a human to edit.
157 *
158 * @return The property value as a string suitable for presentation
159 * to a human to edit.
160 * <p> Returns null if the value can't be expressed as a string.
161 * <p> If a non-null value is returned, then the PropertyEditor should
162 * be prepared to parse that string back in setAsText().
163 */
164 public String getAsText() {
165 return (this.value != null)
166 ? this.value.toString()
167 : null;
168 }
169
170 /**
171 * Sets the property value by parsing a given String. May raise
172 * java.lang.IllegalArgumentException if either the String is
173 * badly formatted or if this kind of property can't be expressed
174 * as text.
175 *
176 * @param text The string to be parsed.
177 */
178 public void setAsText(String text) throws java.lang.IllegalArgumentException {
179 if (value instanceof String) {
180 setValue(text);
181 return;
182 }
183 throw new java.lang.IllegalArgumentException(text);
184 }
185
186 //----------------------------------------------------------------------
187
188 /**
189 * If the property value must be one of a set of known tagged values,
190 * then this method should return an array of the tag values. This can
191 * be used to represent (for example) enum values. If a PropertyEditor
192 * supports tags, then it should support the use of setAsText with
193 * a tag value as a way of setting the value.
194 *
195 * @return The tag values for this property. May be null if this
196 * property cannot be represented as a tagged value.
197 *
198 */
199 public String[] getTags() {
200 return null;
201 }
202
203 //----------------------------------------------------------------------
204
205 /**
206 * A PropertyEditor may chose to make available a full custom Component
207 * that edits its property value. It is the responsibility of the
208 * PropertyEditor to hook itself up to its editor Component itself and
209 * to report property value changes by firing a PropertyChange event.
210 * <P>
211 * The higher-level code that calls getCustomEditor may either embed
212 * the Component in some larger property sheet, or it may put it in
213 * its own individual dialog, or ...
214 *
215 * @return A java.awt.Component that will allow a human to directly
216 * edit the current property value. May be null if this is
217 * not supported.
218 */
219
220 public java.awt.Component getCustomEditor() {
221 return null;
222 }
223
224 /**
225 * Determines whether the propertyEditor can provide a custom editor.
226 *
227 * @return True if the propertyEditor can provide a custom editor.
228 */
229 public boolean supportsCustomEditor() {
230 return false;
231 }
232
233 //----------------------------------------------------------------------
234
235 /**
236 * Adds a listener for the value change.
237 * When the property editor changes its value
238 * it should fire a {@link PropertyChangeEvent}
239 * on all registered {@link PropertyChangeListener}s,
240 * specifying the {@code null} value for the property name.
241 * If the source property is set,
242 * it should be used as the source of the event.
243 * <p>
244 * The same listener object may be added more than once,
245 * and will be called as many times as it is added.
246 * If {@code listener} is {@code null},
247 * no exception is thrown and no action is taken.
248 *
249 * @param listener the {@link PropertyChangeListener} to add
250 */
251 public synchronized void addPropertyChangeListener(
252 PropertyChangeListener listener) {
253 if (listeners == null) {
254 listeners = new java.util.Vector();
255 }
256 listeners.addElement(listener);
257 }
258
259 /**
260 * Removes a listener for the value change.
261 * <p>
262 * If the same listener was added more than once,
263 * it will be notified one less time after being removed.
264 * If {@code listener} is {@code null}, or was never added,
265 * no exception is thrown and no action is taken.
266 *
267 * @param listener the {@link PropertyChangeListener} to remove
268 */
269 public synchronized void removePropertyChangeListener(
270 PropertyChangeListener listener) {
271 if (listeners == null) {
272 return;
273 }
274 listeners.removeElement(listener);
275 }
276
277 /**
278 * Report that we have been modified to any interested listeners.
279 */
280 public void firePropertyChange() {
281 java.util.Vector targets;
282 synchronized (this) {
283 if (listeners == null) {
284 return;
285 }
286 targets = (java.util.Vector) listeners.clone();
287 }
288 // Tell our listeners that "everything" has changed.
289 PropertyChangeEvent evt = new PropertyChangeEvent(source, null, null, null);
290
291 for (int i = 0; i < targets.size(); i++) {
292 PropertyChangeListener target = (PropertyChangeListener)targets.elementAt(i);
293 target.propertyChange(evt);
294 }
295 }
296
297 //----------------------------------------------------------------------
298
299 private Object value;
300 private Object source;
301 private java.util.Vector listeners;
302 }