1 /*
2 * Copyright (c) 1996, 2003, 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 /**
29 * A PropertyEditor class provides support for GUIs that want to
30 * allow users to edit a property value of a given type.
31 * <p>
32 * PropertyEditor supports a variety of different kinds of ways of
33 * displaying and updating property values. Most PropertyEditors will
34 * only need to support a subset of the different options available in
35 * this API.
36 * <P>
37 * Simple PropertyEditors may only support the getAsText and setAsText
38 * methods and need not support (say) paintValue or getCustomEditor. More
39 * complex types may be unable to support getAsText and setAsText but will
40 * instead support paintValue and getCustomEditor.
41 * <p>
42 * Every propertyEditor must support one or more of the three simple
43 * display styles. Thus it can either (1) support isPaintable or (2)
44 * both return a non-null String[] from getTags() and return a non-null
45 * value from getAsText or (3) simply return a non-null String from
46 * getAsText().
47 * <p>
48 * Every property editor must support a call on setValue when the argument
49 * object is of the type for which this is the corresponding propertyEditor.
50 * In addition, each property editor must either support a custom editor,
51 * or support setAsText.
52 * <p>
53 * Each PropertyEditor should have a null constructor.
54 */
55
56 public interface PropertyEditor {
57
58 /**
59 * Set (or change) the object that is to be edited. Primitive types such
60 * as "int" must be wrapped as the corresponding object type such as
61 * "java.lang.Integer".
62 *
63 * @param value The new target object to be edited. Note that this
64 * object should not be modified by the PropertyEditor, rather
65 * the PropertyEditor should create a new object to hold any
66 * modified value.
67 */
68 void setValue(Object value);
69
70 /**
71 * Gets the property value.
72 *
73 * @return The value of the property. Primitive types such as "int" will
74 * be wrapped as the corresponding object type such as "java.lang.Integer".
75 */
76
77 Object getValue();
78
79 //----------------------------------------------------------------------
80
81 /**
82 * Determines whether this property editor is paintable.
83 *
84 * @return True if the class will honor the paintValue method.
85 */
86
87 boolean isPaintable();
88
89 /**
90 * Paint a representation of the value into a given area of screen
91 * real estate. Note that the propertyEditor is responsible for doing
92 * its own clipping so that it fits into the given rectangle.
93 * <p>
94 * If the PropertyEditor doesn't honor paint requests (see isPaintable)
95 * this method should be a silent noop.
96 * <p>
97 * The given Graphics object will have the default font, color, etc of
98 * the parent container. The PropertyEditor may change graphics attributes
99 * such as font and color and doesn't need to restore the old values.
100 *
101 * @param gfx Graphics object to paint into.
102 * @param box Rectangle within graphics object into which we should paint.
103 */
104 void paintValue(java.awt.Graphics gfx, java.awt.Rectangle box);
105
106 //----------------------------------------------------------------------
107
108 /**
109 * Returns a fragment of Java code that can be used to set a property
110 * to match the editors current state. This method is intended
111 * for use when generating Java code to reflect changes made through the
112 * property editor.
113 * <p>
114 * The code fragment should be context free and must be a legal Java
115 * expression as specified by the JLS.
116 * <p>
117 * Specifically, if the expression represents a computation then all
118 * classes and static members should be fully qualified. This rule
119 * applies to constructors, static methods and non primitive arguments.
120 * <p>
121 * Caution should be used when evaluating the expression as it may throw
122 * exceptions. In particular, code generators must ensure that generated
123 * code will compile in the presence of an expression that can throw
124 * checked exceptions.
125 * <p>
126 * Example results are:
127 * <ul>
128 * <li>Primitive expresssion: <code>2</code>
129 * <li>Class constructor: <code>new java.awt.Color(127,127,34)</code>
130 * <li>Static field: <code>java.awt.Color.orange</code>
131 * <li>Static method: <code>javax.swing.Box.createRigidArea(new
132 * java.awt.Dimension(0, 5))</code>
133 * </ul>
134 *
135 * @return a fragment of Java code representing an initializer for the
136 * current value. It should not contain a semi-colon
137 * ('<code>;</code>') to end the expression.
138 */
139 String getJavaInitializationString();
140
141 //----------------------------------------------------------------------
142
143 /**
144 * Gets the property value as text.
145 *
146 * @return The property value as a human editable string.
147 * <p> Returns null if the value can't be expressed as an editable string.
148 * <p> If a non-null value is returned, then the PropertyEditor should
149 * be prepared to parse that string back in setAsText().
150 */
151 String getAsText();
152
153 /**
154 * Set the property value by parsing a given String. May raise
155 * java.lang.IllegalArgumentException if either the String is
156 * badly formatted or if this kind of property can't be expressed
157 * as text.
158 * @param text The string to be parsed.
159 */
160 void setAsText(String text) throws java.lang.IllegalArgumentException;
161
162 //----------------------------------------------------------------------
163
164 /**
165 * If the property value must be one of a set of known tagged values,
166 * then this method should return an array of the tags. This can
167 * be used to represent (for example) enum values. If a PropertyEditor
168 * supports tags, then it should support the use of setAsText with
169 * a tag value as a way of setting the value and the use of getAsText
170 * to identify the current value.
171 *
172 * @return The tag values for this property. May be null if this
173 * property cannot be represented as a tagged value.
174 *
175 */
176 String[] getTags();
177
178 //----------------------------------------------------------------------
179
180 /**
181 * A PropertyEditor may choose to make available a full custom Component
182 * that edits its property value. It is the responsibility of the
183 * PropertyEditor to hook itself up to its editor Component itself and
184 * to report property value changes by firing a PropertyChange event.
185 * <P>
186 * The higher-level code that calls getCustomEditor may either embed
187 * the Component in some larger property sheet, or it may put it in
188 * its own individual dialog, or ...
189 *
190 * @return A java.awt.Component that will allow a human to directly
191 * edit the current property value. May be null if this is
192 * not supported.
193 */
194
195 java.awt.Component getCustomEditor();
196
197 /**
198 * Determines whether this property editor supports a custom editor.
199 *
200 * @return True if the propertyEditor can provide a custom editor.
201 */
202 boolean supportsCustomEditor();
203
204 //----------------------------------------------------------------------
205
206 /**
207 * Adds a listener for the value change.
208 * When the property editor changes its value
209 * it should fire a {@link PropertyChangeEvent}
210 * on all registered {@link PropertyChangeListener}s,
211 * specifying the {@code null} value for the property name
212 * and itself as the source.
213 *
214 * @param listener the {@link PropertyChangeListener} to add
215 */
216 void addPropertyChangeListener(PropertyChangeListener listener);
217
218 /**
219 * Removes a listener for the value change.
220 *
221 * @param listener the {@link PropertyChangeListener} to remove
222 */
223 void removePropertyChangeListener(PropertyChangeListener listener);
224
225 }