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 * @since 1.1
56 */
57
58 public interface PropertyEditor {
59
60 /**
61 * Set (or change) the object that is to be edited. Primitive types such
62 * as "int" must be wrapped as the corresponding object type such as
63 * "java.lang.Integer".
64 *
65 * @param value The new target object to be edited. Note that this
66 * object should not be modified by the PropertyEditor, rather
67 * the PropertyEditor should create a new object to hold any
68 * modified value.
69 */
70 void setValue(Object value);
71
72 /**
73 * Gets the property value.
74 *
75 * @return The value of the property. Primitive types such as "int" will
76 * be wrapped as the corresponding object type such as "java.lang.Integer".
77 */
78
79 Object getValue();
80
81 //----------------------------------------------------------------------
82
83 /**
84 * Determines whether this property editor is paintable.
85 *
86 * @return True if the class will honor the paintValue method.
87 */
88
89 boolean isPaintable();
90
91 /**
92 * Paint a representation of the value into a given area of screen
93 * real estate. Note that the propertyEditor is responsible for doing
94 * its own clipping so that it fits into the given rectangle.
95 * <p>
96 * If the PropertyEditor doesn't honor paint requests (see isPaintable)
97 * this method should be a silent noop.
98 * <p>
99 * The given Graphics object will have the default font, color, etc of
100 * the parent container. The PropertyEditor may change graphics attributes
101 * such as font and color and doesn't need to restore the old values.
102 *
103 * @param gfx Graphics object to paint into.
104 * @param box Rectangle within graphics object into which we should paint.
105 */
106 void paintValue(java.awt.Graphics gfx, java.awt.Rectangle box);
107
108 //----------------------------------------------------------------------
109
110 /**
111 * Returns a fragment of Java code that can be used to set a property
112 * to match the editors current state. This method is intended
113 * for use when generating Java code to reflect changes made through the
114 * property editor.
115 * <p>
116 * The code fragment should be context free and must be a legal Java
117 * expression as specified by the JLS.
118 * <p>
119 * Specifically, if the expression represents a computation then all
120 * classes and static members should be fully qualified. This rule
121 * applies to constructors, static methods and non primitive arguments.
122 * <p>
123 * Caution should be used when evaluating the expression as it may throw
124 * exceptions. In particular, code generators must ensure that generated
125 * code will compile in the presence of an expression that can throw
126 * checked exceptions.
127 * <p>
128 * Example results are:
129 * <ul>
130 * <li>Primitive expresssion: <code>2</code>
131 * <li>Class constructor: <code>new java.awt.Color(127,127,34)</code>
132 * <li>Static field: <code>java.awt.Color.orange</code>
133 * <li>Static method: <code>javax.swing.Box.createRigidArea(new
134 * java.awt.Dimension(0, 5))</code>
135 * </ul>
136 *
137 * @return a fragment of Java code representing an initializer for the
138 * current value. It should not contain a semi-colon
139 * ('<code>;</code>') to end the expression.
140 */
141 String getJavaInitializationString();
142
143 //----------------------------------------------------------------------
144
145 /**
146 * Gets the property value as text.
147 *
148 * @return The property value as a human editable string.
149 * <p> Returns null if the value can't be expressed as an editable string.
150 * <p> If a non-null value is returned, then the PropertyEditor should
151 * be prepared to parse that string back in setAsText().
152 */
153 String getAsText();
154
155 /**
156 * Set the property value by parsing a given String. May raise
157 * java.lang.IllegalArgumentException if either the String is
158 * badly formatted or if this kind of property can't be expressed
159 * as text.
160 * @param text The string to be parsed.
161 */
162 void setAsText(String text) throws java.lang.IllegalArgumentException;
163
164 //----------------------------------------------------------------------
165
166 /**
167 * If the property value must be one of a set of known tagged values,
168 * then this method should return an array of the tags. This can
169 * be used to represent (for example) enum values. If a PropertyEditor
170 * supports tags, then it should support the use of setAsText with
171 * a tag value as a way of setting the value and the use of getAsText
172 * to identify the current value.
173 *
174 * @return The tag values for this property. May be null if this
175 * property cannot be represented as a tagged value.
176 *
177 */
178 String[] getTags();
179
180 //----------------------------------------------------------------------
181
182 /**
183 * A PropertyEditor may choose to make available a full custom Component
184 * that edits its property value. It is the responsibility of the
185 * PropertyEditor to hook itself up to its editor Component itself and
186 * to report property value changes by firing a PropertyChange event.
187 * <P>
188 * The higher-level code that calls getCustomEditor may either embed
189 * the Component in some larger property sheet, or it may put it in
190 * its own individual dialog, or ...
191 *
192 * @return A java.awt.Component that will allow a human to directly
193 * edit the current property value. May be null if this is
194 * not supported.
195 */
196
197 java.awt.Component getCustomEditor();
198
199 /**
200 * Determines whether this property editor supports a custom editor.
201 *
202 * @return True if the propertyEditor can provide a custom editor.
203 */
204 boolean supportsCustomEditor();
205
206 //----------------------------------------------------------------------
207
208 /**
209 * Adds a listener for the value change.
210 * When the property editor changes its value
211 * it should fire a {@link PropertyChangeEvent}
212 * on all registered {@link PropertyChangeListener}s,
213 * specifying the {@code null} value for the property name
214 * and itself as the source.
215 *
216 * @param listener the {@link PropertyChangeListener} to add
217 */
218 void addPropertyChangeListener(PropertyChangeListener listener);
219
220 /**
221 * Removes a listener for the value change.
222 *
223 * @param listener the {@link PropertyChangeListener} to remove
224 */
225 void removePropertyChangeListener(PropertyChangeListener listener);
226
227 }