001    /* java.beans.PropertyEditorManager
002       Copyright (C) 1998 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010     
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.beans;
040    
041    import gnu.java.beans.editors.ColorEditor;
042    import gnu.java.beans.editors.FontEditor;
043    import gnu.java.beans.editors.NativeBooleanEditor;
044    import gnu.java.beans.editors.NativeByteEditor;
045    import gnu.java.beans.editors.NativeDoubleEditor;
046    import gnu.java.beans.editors.NativeFloatEditor;
047    import gnu.java.beans.editors.NativeIntEditor;
048    import gnu.java.beans.editors.NativeLongEditor;
049    import gnu.java.beans.editors.NativeShortEditor;
050    import gnu.java.beans.editors.StringEditor;
051    import gnu.java.lang.ClassHelper;
052    
053    import java.awt.Color;
054    import java.awt.Font;
055    
056    /**
057     * PropertyEditorManager is used to find property editors
058     * for various types (not necessarily Beans).<P>
059     *
060     * It first checks to see if the property editor is
061     * already registered; if it is, that property editor is
062     * used.  Next it takes the type's classname and appends
063     * "Editor" to it, and searches first in the class's
064     * package and then in the property editor search path.
065     *
066     * <p>Default property editors are provided for:</p>
067     * 
068     * <ol>
069     * <li>boolean, byte, short, int, long, float, and double</li>
070     * <li>java.lang.String</li>
071     * <li>java.awt.Color</li>
072     * <li>java.awt.Font</li>
073     * </ol>
074     *
075     * <p><strong>Spec Suggestion:</strong> Perhaps an editor for
076     * Filename or something like it should be provided.  As well
077     * as char.</p>
078     *
079     * @author John Keiser
080     * @since 1.1
081     * @version 1.1.0, 29 Jul 1998
082     */
083    
084    public class PropertyEditorManager
085    {
086      static java.util.Hashtable<Class<?>,Class<?>> editors =
087        new java.util.Hashtable<Class<?>,Class<?>>();
088      static String[] editorSearchPath = { "gnu.java.beans.editors",
089                                           "sun.beans.editors" };
090    
091      static
092        {
093          registerEditor(Boolean.TYPE, NativeBooleanEditor.class);
094          registerEditor(Byte.TYPE,    NativeByteEditor.class);
095          registerEditor(Short.TYPE,   NativeShortEditor.class);
096          registerEditor(Integer.TYPE, NativeIntEditor.class);
097          registerEditor(Long.TYPE,    NativeLongEditor.class);
098          registerEditor(Float.TYPE,   NativeFloatEditor.class);
099          registerEditor(Double.TYPE,  NativeDoubleEditor.class);
100          registerEditor(String.class, StringEditor.class);
101          registerEditor(Color.class,  ColorEditor.class);
102          registerEditor(Font.class,   FontEditor.class);
103        }
104    
105      /**
106       * Beats me why this class can be instantiated, but there
107       * you have it.
108       */
109      public PropertyEditorManager()
110      {
111        // Do nothing here
112      }
113    
114      /**
115       * Register an editor for a class.  Replaces old editor
116       * if there was one registered before.
117       *
118       * @param editedClass the class that the property editor
119       *        will edit.
120       * @param editorClass the PropertyEditor class.
121       */
122      public static void registerEditor(Class<?> editedClass, Class<?> editorClass)
123      {
124        editors.put(editedClass, editorClass);
125      }
126    
127      /**
128       * Returns a new instance of the property editor for the
129       * specified class.
130       *
131       * @param editedClass the class that the property editor
132       *        will edit.
133       * @return a PropertyEditor instance that can edit the
134       *         specified class.
135       */
136      public static PropertyEditor findEditor(Class<?> editedClass)
137      {
138        try
139          {
140            Class found = (Class)editors.get(editedClass);
141            if(found != null)
142              {
143                return (PropertyEditor)found.newInstance();
144              }
145    
146            ClassLoader contextClassLoader
147                    = Thread.currentThread().getContextClassLoader();
148    
149            try
150              {
151                found = Class.forName(editedClass.getName()+"Editor", true,
152                                      contextClassLoader);
153                registerEditor(editedClass,found);
154                return (PropertyEditor)found.newInstance();
155              }
156            catch(ClassNotFoundException E)
157              {
158              }
159    
160            String appendName
161                    = "."
162                    + ClassHelper.getTruncatedClassName(editedClass)
163                    + "Editor";
164            synchronized(editorSearchPath)
165              {
166                for(int i=0;i<editorSearchPath.length;i++)
167                  {
168                    try
169                      {
170                        found = Class.forName(editorSearchPath[i] + appendName,
171                                              true, contextClassLoader);
172                        registerEditor(editedClass,found);
173                        return (PropertyEditor)found.newInstance();
174                      }
175                    catch(ClassNotFoundException E)
176                      {
177                      }
178                  }
179              }
180          }
181        catch(InstantiationException E)
182          {
183          }
184        catch(IllegalAccessException E)
185          {
186          }
187        
188        return null;
189      }
190    
191      /**
192       * Get the editor search path.
193       * As a minor departure from the spec, the default value
194       * for the editor search path is "gnu.java.beans.editors",
195       * "sun.beans.editors".
196       *
197       * @return the editor search path.
198       */
199      public static String[] getEditorSearchPath()
200      {
201        return editorSearchPath;
202      }
203    
204      /**
205       * Set the editor search path.
206       *
207       * @param editorSearchPath the new value for the editor search path.
208       */
209      public static void setEditorSearchPath(String[] editorSearchPath)
210      {
211        synchronized(editorSearchPath)
212          {
213            PropertyEditorManager.editorSearchPath = editorSearchPath;
214          }
215      }
216    }