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    1   /*
    2    * Copyright (c) 1997, 2008, 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   package javax.swing.text;
   26   
   27   import java.awt.event.ActionEvent;
   28   import java.awt.KeyboardFocusManager;
   29   import java.awt.Component;
   30   import java.util.Hashtable;
   31   import java.util.Enumeration;
   32   import javax.swing.Action;
   33   import javax.swing.AbstractAction;
   34   import javax.swing.KeyStroke;
   35   
   36   /**
   37    * An Action implementation useful for key bindings that are
   38    * shared across a number of different text components.  Because
   39    * the action is shared, it must have a way of getting it's
   40    * target to act upon.  This class provides support to try and
   41    * find a text component to operate on.  The preferred way of
   42    * getting the component to act upon is through the ActionEvent
   43    * that is received.  If the Object returned by getSource can
   44    * be narrowed to a text component, it will be used.  If the
   45    * action event is null or can't be narrowed, the last focused
   46    * text component is tried.  This is determined by being
   47    * used in conjunction with a JTextController which
   48    * arranges to share that information with a TextAction.
   49    * <p>
   50    * <strong>Warning:</strong>
   51    * Serialized objects of this class will not be compatible with
   52    * future Swing releases. The current serialization support is
   53    * appropriate for short term storage or RMI between applications running
   54    * the same version of Swing.  As of 1.4, support for long term storage
   55    * of all JavaBeans<sup><font size="-2">TM</font></sup>
   56    * has been added to the <code>java.beans</code> package.
   57    * Please see {@link java.beans.XMLEncoder}.
   58    *
   59    * @author  Timothy Prinzing
   60    */
   61   public abstract class TextAction extends AbstractAction {
   62   
   63       /**
   64        * Creates a new JTextAction object.
   65        *
   66        * @param name the name of the action
   67        */
   68       public TextAction(String name) {
   69           super(name);
   70       }
   71   
   72       /**
   73        * Determines the component to use for the action.
   74        * This if fetched from the source of the ActionEvent
   75        * if it's not null and can be narrowed.  Otherwise,
   76        * the last focused component is used.
   77        *
   78        * @param e the ActionEvent
   79        * @return the component
   80        */
   81       protected final JTextComponent getTextComponent(ActionEvent e) {
   82           if (e != null) {
   83               Object o = e.getSource();
   84               if (o instanceof JTextComponent) {
   85                   return (JTextComponent) o;
   86               }
   87           }
   88           return getFocusedComponent();
   89       }
   90   
   91       /**
   92        * Takes one list of
   93        * commands and augments it with another list
   94        * of commands.  The second list takes precedence
   95        * over the first list; that is, when both lists
   96        * contain a command with the same name, the command
   97        * from the second list is used.
   98        *
   99        * @param list1 the first list, may be empty but not
  100        *              <code>null</code>
  101        * @param list2 the second list, may be empty but not
  102        *              <code>null</code>
  103        * @return the augmented list
  104        */
  105       public static final Action[] augmentList(Action[] list1, Action[] list2) {
  106           Hashtable<String, Action> h = new Hashtable<String, Action>();
  107           for (Action a : list1) {
  108               String value = (String)a.getValue(Action.NAME);
  109               h.put((value!=null ? value:""), a);
  110           }
  111           for (Action a : list2) {
  112               String value = (String)a.getValue(Action.NAME);
  113               h.put((value!=null ? value:""), a);
  114           }
  115           Action[] actions = new Action[h.size()];
  116           int index = 0;
  117           for (Enumeration e = h.elements() ; e.hasMoreElements() ;) {
  118               actions[index++] = (Action) e.nextElement();
  119           }
  120           return actions;
  121       }
  122   
  123       /**
  124        * Fetches the text component that currently has focus.
  125        * This allows actions to be shared across text components
  126        * which is useful for key-bindings where a large set of
  127        * actions are defined, but generally used the same way
  128        * across many different components.
  129        *
  130        * @return the component
  131        */
  132       protected final JTextComponent getFocusedComponent() {
  133           return JTextComponent.getFocusedComponent();
  134       }
  135   }

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