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    1   /*
    2    * Copyright (c) 1996, 2010, 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
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   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
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   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 com.sun.beans.finder.PropertyEditorFinder;
   29   import sun.awt.AppContext;
   30   
   31   /**
   32    * The PropertyEditorManager can be used to locate a property editor for
   33    * any given type name.  This property editor must support the
   34    * java.beans.PropertyEditor interface for editing a given object.
   35    * <P>
   36    * The PropertyEditorManager uses three techniques for locating an editor
   37    * for a given type.  First, it provides a registerEditor method to allow
   38    * an editor to be specifically registered for a given type.  Second it
   39    * tries to locate a suitable class by adding "Editor" to the full
   40    * qualified classname of the given type (e.g. "foo.bah.FozEditor").
   41    * Finally it takes the simple classname (without the package name) adds
   42    * "Editor" to it and looks in a search-path of packages for a matching
   43    * class.
   44    * <P>
   45    * So for an input class foo.bah.Fred, the PropertyEditorManager would
   46    * first look in its tables to see if an editor had been registered for
   47    * foo.bah.Fred and if so use that.  Then it will look for a
   48    * foo.bah.FredEditor class.  Then it will look for (say)
   49    * standardEditorsPackage.FredEditor class.
   50    * <p>
   51    * Default PropertyEditors will be provided for the Java primitive types
   52    * "boolean", "byte", "short", "int", "long", "float", and "double"; and
   53    * for the classes java.lang.String. java.awt.Color, and java.awt.Font.
   54    */
   55   
   56   public class PropertyEditorManager {
   57   
   58       private static final Object FINDER_KEY = new Object();
   59   
   60       /**
   61        * Registers an editor class to edit values of the given target class.
   62        * If the editor class is {@code null},
   63        * then any existing definition will be removed.
   64        * Thus this method can be used to cancel the registration.
   65        * The registration is canceled automatically
   66        * if either the target or editor class is unloaded.
   67        * <p>
   68        * If there is a security manager, its {@code checkPropertiesAccess}
   69        * method is called. This could result in a {@linkplain SecurityException}.
   70        *
   71        * @param targetType   the class object of the type to be edited
   72        * @param editorClass  the class object of the editor class
   73        * @throws SecurityException  if a security manager exists and
   74        *                            its {@code checkPropertiesAccess} method
   75        *                            doesn't allow setting of system properties
   76        *
   77        * @see SecurityManager#checkPropertiesAccess
   78        */
   79       public static void registerEditor(Class<?> targetType, Class<?> editorClass) {
   80           SecurityManager sm = System.getSecurityManager();
   81           if (sm != null) {
   82               sm.checkPropertiesAccess();
   83           }
   84           getFinder().register(targetType, editorClass);
   85       }
   86   
   87       /**
   88        * Locate a value editor for a given target type.
   89        *
   90        * @param targetType  The Class object for the type to be edited
   91        * @return An editor object for the given target class.
   92        * The result is null if no suitable editor can be found.
   93        */
   94       public static PropertyEditor findEditor(Class<?> targetType) {
   95           return getFinder().find(targetType);
   96       }
   97   
   98       /**
   99        * Gets the package names that will be searched for property editors.
  100        *
  101        * @return  The array of package names that will be searched in
  102        *          order to find property editors.
  103        * <p>     The default value for this array is implementation-dependent,
  104        *         e.g. Sun implementation initially sets to  {"sun.beans.editors"}.
  105        */
  106       public static String[] getEditorSearchPath() {
  107           return getFinder().getPackages();
  108       }
  109   
  110       /**
  111        * Change the list of package names that will be used for
  112        *          finding property editors.
  113        *
  114        * <p>First, if there is a security manager, its <code>checkPropertiesAccess</code>
  115        * method is called. This could result in a SecurityException.
  116        *
  117        * @param path  Array of package names.
  118        * @exception  SecurityException  if a security manager exists and its
  119        *             <code>checkPropertiesAccess</code> method doesn't allow setting
  120        *              of system properties.
  121        * @see SecurityManager#checkPropertiesAccess
  122        */
  123       public static void setEditorSearchPath(String[] path) {
  124           SecurityManager sm = System.getSecurityManager();
  125           if (sm != null) {
  126               sm.checkPropertiesAccess();
  127           }
  128           getFinder().setPackages(path);
  129       }
  130   
  131       private static PropertyEditorFinder getFinder() {
  132           AppContext context = AppContext.getAppContext();
  133           Object object = context.get(FINDER_KEY);
  134           if (object instanceof PropertyEditorFinder) {
  135               return (PropertyEditorFinder) object;
  136           }
  137           PropertyEditorFinder finder = new PropertyEditorFinder();
  138           context.put(FINDER_KEY, finder);
  139           return finder;
  140       }
  141   }

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