1 /*
2 * Copyright 1996-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.beans;
27
28 import sun.beans.editors;
29
30 /**
31 * The PropertyEditorManager can be used to locate a property editor for
32 * any given type name. This property editor must support the
33 * java.beans.PropertyEditor interface for editing a given object.
34 * <P>
35 * The PropertyEditorManager uses three techniques for locating an editor
36 * for a given type. First, it provides a registerEditor method to allow
37 * an editor to be specifically registered for a given type. Second it
38 * tries to locate a suitable class by adding "Editor" to the full
39 * qualified classname of the given type (e.g. "foo.bah.FozEditor").
40 * Finally it takes the simple classname (without the package name) adds
41 * "Editor" to it and looks in a search-path of packages for a matching
42 * class.
43 * <P>
44 * So for an input class foo.bah.Fred, the PropertyEditorManager would
45 * first look in its tables to see if an editor had been registered for
46 * foo.bah.Fred and if so use that. Then it will look for a
47 * foo.bah.FredEditor class. Then it will look for (say)
48 * standardEditorsPackage.FredEditor class.
49 * <p>
50 * Default PropertyEditors will be provided for the Java primitive types
51 * "boolean", "byte", "short", "int", "long", "float", and "double"; and
52 * for the classes java.lang.String. java.awt.Color, and java.awt.Font.
53 */
54
55 public class PropertyEditorManager {
56
57 /**
58 * Register an editor class to be used to edit values of
59 * a given target class.
60 *
61 * <p>First, if there is a security manager, its <code>checkPropertiesAccess</code>
62 * method is called. This could result in a SecurityException.
63 *
64 * @param targetType the Class object of the type to be edited
65 * @param editorClass the Class object of the editor class. If
66 * this is null, then any existing definition will be removed.
67 * @exception SecurityException if a security manager exists and its
68 * <code>checkPropertiesAccess</code> method doesn't allow setting
69 * of system properties.
70 * @see SecurityManager#checkPropertiesAccess
71 */
72
73 public static void registerEditor(Class<?> targetType, Class<?> editorClass) {
74 SecurityManager sm = System.getSecurityManager();
75 if (sm != null) {
76 sm.checkPropertiesAccess();
77 }
78 initialize();
79 if (editorClass == null) {
80 registry.remove(targetType);
81 } else {
82 registry.put(targetType, editorClass);
83 }
84 }
85
86 /**
87 * Locate a value editor for a given target type.
88 *
89 * @param targetType The Class object for the type to be edited
90 * @return An editor object for the given target class.
91 * The result is null if no suitable editor can be found.
92 */
93
94 public static synchronized PropertyEditor findEditor(Class<?> targetType) {
95 initialize();
96 Class editorClass = (Class)registry.get(targetType);
97 if (editorClass != null) {
98 try {
99 Object o = editorClass.newInstance();
100 return (PropertyEditor)o;
101 } catch (Exception ex) {
102 System.err.println("Couldn't instantiate type editor \"" +
103 editorClass.getName() + "\" : " + ex);
104 }
105 }
106
107 // Now try adding "Editor" to the class name.
108
109 String editorName = targetType.getName() + "Editor";
110 try {
111 return (PropertyEditor) Introspector.instantiate(targetType, editorName);
112 } catch (Exception ex) {
113 // Silently ignore any errors.
114 }
115
116 // Now try looking for <searchPath>.fooEditor
117 int index = editorName.lastIndexOf('.') + 1;
118 if (index > 0) {
119 editorName = editorName.substring(index);
120 }
121 for (String path : searchPath) {
122 String name = path + '.' + editorName;
123 try {
124 return (PropertyEditor) Introspector.instantiate(targetType, name);
125 } catch (Exception ex) {
126 // Silently ignore any errors.
127 }
128 }
129
130 if (null != targetType.getEnumConstants()) {
131 return new EnumEditor(targetType);
132 }
133 // We couldn't find a suitable Editor.
134 return null;
135 }
136
137 /**
138 * Gets the package names that will be searched for property editors.
139 *
140 * @return The array of package names that will be searched in
141 * order to find property editors.
142 * <p> The default value for this array is implementation-dependent,
143 * e.g. Sun implementation initially sets to {"sun.beans.editors"}.
144 */
145 public static synchronized String[] getEditorSearchPath() {
146 // Return a copy of the searchPath.
147 String result[] = new String[searchPath.length];
148 System.arraycopy(searchPath, 0, result, 0, searchPath.length);
149 return result;
150 }
151
152 /**
153 * Change the list of package names that will be used for
154 * finding property editors.
155 *
156 * <p>First, if there is a security manager, its <code>checkPropertiesAccess</code>
157 * method is called. This could result in a SecurityException.
158 *
159 * @param path Array of package names.
160 * @exception SecurityException if a security manager exists and its
161 * <code>checkPropertiesAccess</code> method doesn't allow setting
162 * of system properties.
163 * @see SecurityManager#checkPropertiesAccess
164 */
165
166 public static synchronized void setEditorSearchPath(String path[]) {
167 SecurityManager sm = System.getSecurityManager();
168 if (sm != null) {
169 sm.checkPropertiesAccess();
170 }
171 if (path == null) {
172 path = new String[0];
173 }
174 searchPath = path;
175 }
176
177 private static synchronized void initialize() {
178 if (registry != null) {
179 return;
180 }
181 registry = new java.util.Hashtable();
182 registry.put(Byte.TYPE, ByteEditor.class);
183 registry.put(Short.TYPE, ShortEditor.class);
184 registry.put(Integer.TYPE, IntegerEditor.class);
185 registry.put(Long.TYPE, LongEditor.class);
186 registry.put(Boolean.TYPE, BooleanEditor.class);
187 registry.put(Float.TYPE, FloatEditor.class);
188 registry.put(Double.TYPE, DoubleEditor.class);
189 }
190
191 private static String[] searchPath = { "sun.beans.editors" };
192 private static java.util.Hashtable registry;
193 }
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