001    /* ActionMap.java --
002       Copyright (C) 2002, 2004, 2006, 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    package javax.swing;
039    
040    import java.io.Serializable;
041    import java.util.Arrays;
042    import java.util.HashMap;
043    import java.util.HashSet;
044    import java.util.Map;
045    import java.util.Set;
046    
047    
048    /**
049     * Maps arbitrary keys (usually Strings) to {@link Action} instances. This
050     * is used in combination with {@link InputMap}s.
051     *
052     * If a component receives an input event, this is looked up in
053     * the component's <code>InputMap</code>. The result is an object which
054     * serves as a key to the components <code>ActionMap</code>. Finally
055     * the <code>Action</code> that is stored is executed.
056     *
057     * @author Andrew Selkirk
058     * @author Michael Koch
059     */
060    public class ActionMap
061      implements Serializable
062    {
063      private static final long serialVersionUID = -6277518704513986346L;
064    
065      /**
066       * actionMap
067       */
068      private Map actionMap = new HashMap();
069    
070      /**
071       * parent
072       */
073      private ActionMap parent;
074    
075      /**
076       * Creates a new <code>ActionMap</code> instance.
077       */
078      public ActionMap()
079      {
080        // Nothing to do here.
081      }
082    
083      /**
084       * Returns an action associated with an object.
085       *
086       * @param key the key of the enty
087       *
088       * @return the action associated with key, may be null
089       */
090      public Action get(Object key)
091      {
092        Object result = actionMap.get(key);
093    
094        if (result == null && parent != null)
095          result = parent.get(key);
096    
097        return (Action) result;
098      }
099    
100      /**
101       * Puts a new <code>Action</code> into the <code>ActionMap</code>.
102       * If action is null an existing entry will be removed.
103       *
104       * @param key the key for the entry
105       * @param action the action.
106       */
107      public void put(Object key, Action action)
108      {
109        if (action == null)
110          actionMap.remove(key);
111        else
112          actionMap.put(key, action);
113      }
114    
115      /**
116       * Remove an entry from the <code>ActionMap</code>.
117       *
118       * @param key the key of the entry to remove
119       */
120      public void remove(Object key)
121      {
122        actionMap.remove(key);
123      }
124    
125      /**
126       * Returns the parent of this <code>ActionMap</code>.
127       *
128       * @return the parent, may be null.
129       */
130      public ActionMap getParent()
131      {
132        return parent;
133      }
134    
135      /**
136       * Sets a parent for this <code>ActionMap</code>.
137       *
138       * @param parentMap the new parent
139       */
140      public void setParent(ActionMap parentMap)
141      {
142        if (parentMap != this)
143          parent = parentMap;
144      }
145    
146      /**
147       * Returns the number of entries in this <code>ActionMap</code>.
148       *
149       * @return the number of entries
150       */
151      public int size()
152      {
153        return actionMap.size();
154      }
155    
156      /**
157       * Clears the <code>ActionMap</code>.
158       */
159      public void clear()
160      {
161        actionMap.clear();
162      }
163    
164      /**
165       * Returns all keys of entries in this <code>ActionMap</code>.
166       *
167       * @return an array of keys
168       */
169      public Object[] keys()
170      {
171        if (size() != 0)
172          return actionMap.keySet().toArray();
173        return null;
174      }
175    
176      /**
177       * Returns all keys of entries in this <code>ActionMap</code>
178       * and all its parents.
179       *
180       * @return an array of keys
181       */
182      public Object[] allKeys()
183      {
184        Set set = new HashSet();
185    
186        if (parent != null)
187          set.addAll(Arrays.asList(parent.allKeys()));
188    
189        set.addAll(actionMap.keySet());
190        if (set.size() != 0)
191          return set.toArray();
192        return null;
193      }
194    
195    }