AbstractAction


1   /*
2    * @(#)AbstractAction.java  1.51 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   package javax.swing;
8   
9   import java.awt.*;
10  import java.awt.event.*;
11  import java.beans.*;
12  import java.util.Hashtable  ;
13  import java.util.Enumeration  ;
14  import java.io.Serializable  ;
15  import java.io.IOException  ;
16  import java.io.ObjectInputStream  ;
17  import java.io.ObjectOutputStream  ;
18  import javax.swing.event.SwingPropertyChangeSupport  ;
19  
20  /**
21   * This class provides default implementations for the JFC <code>Action</code> 
22   * interface. Standard behaviors like the get and set methods for
23   * <code>Action</code> object properties (icon, text, and enabled) are defined
24   * here. The developer need only subclass this abstract class and
25   * define the <code>actionPerformed</code> method. 
26   * <p>
27   * <strong>Warning:</strong>
28   * Serialized objects of this class will not be compatible with
29   * future Swing releases. The current serialization support is
30   * appropriate for short term storage or RMI between applications running
31   * the same version of Swing.  As of 1.4, support for long term storage
32   * of all JavaBeans<sup><font size="-2">TM</font></sup>
33   * has been added to the <code>java.beans</code> package.
34   * Please see {@link java.beans.XMLEncoder}.
35   *
36   * @version 1.51 12/19/03
37   * @author Georges Saab
38   * @see Action
39   */
40  public abstract class AbstractAction implements Action  , Cloneable  , Serializable   
41  {
42      /**
43       * Specifies whether action is enabled; the default is true.
44       */
45      protected boolean enabled = true;
46  
47  
48      /**
49       * Contains the array of key bindings.
50       */
51      private transient ArrayTable   arrayTable;
52      
53      /**
54       * Defines an <code>Action</code> object with a default
55       * description string and default icon.
56       */
57      public AbstractAction() {
58      }
59      
60      /**
61       * Defines an <code>Action</code> object with the specified
62       * description string and a default icon.
63       */
64      public AbstractAction(String   name) {
65      putValue(Action.NAME, name);
66      }
67  
68      /**
69       * Defines an <code>Action</code> object with the specified
70       * description string and a the specified icon.
71       */
72      public AbstractAction(String   name, Icon   icon) {
73      this(name);
74      putValue(Action.SMALL_ICON, icon);
75      }
76      
77      /** 
78       * Gets the <code>Object</code> associated with the specified key.
79       *
80       * @param key a string containing the specified <code>key</code>
81       * @return the binding <code>Object</code> stored with this key; if there
82       *      are no keys, it will return <code>null</code>
83       * @see Action#getValue
84       */
85      public Object   getValue(String   key) {
86      if (arrayTable == null) {
87          return null;
88      }
89      return arrayTable.get(key);
90      }
91      
92      /** 
93       * Sets the <code>Value</code> associated with the specified key.
94       *
95       * @param key  the <code>String</code> that identifies the stored object
96       * @param newValue the <code>Object</code> to store using this key
97       * @see Action#putValue 
98       */
99      public void putValue(String   key, Object   newValue) {
100     Object   oldValue = null;
101     if (arrayTable == null) {
102         arrayTable = new ArrayTable  ();
103     }
104     if (arrayTable.containsKey(key))
105         oldValue = arrayTable.get(key);
106     // Remove the entry for key if newValue is null
107     // else put in the newValue for key.
108     if (newValue == null) {
109         arrayTable.remove(key);
110     } else {
111         arrayTable.put(key,newValue);
112     }
113     firePropertyChange(key, oldValue, newValue);
114     }
115 
116     /**
117      * Returns true if the action is enabled.
118      *
119      * @return true if the action is enabled, false otherwise
120      * @see Action#isEnabled
121      */
122     public boolean isEnabled() {
123     return enabled;
124     }
125 
126     /**
127      * Enables or disables the action.
128      *
129      * @param newValue  true to enable the action, false to
130      *                  disable it
131      * @see Action#setEnabled
132      */
133     public void setEnabled(boolean newValue) {
134     boolean oldValue = this.enabled;
135 
136     if (oldValue != newValue) {
137         this.enabled = newValue;
138         firePropertyChange("enabled", 
139                    Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
140     }
141     }
142 
143 
144     /**
145      * Returns an array of <code>Object</code>s which are keys for
146      * which values have been set for this <code>AbstractAction</code>,
147      * or <code>null</code> if no keys have values set.
148      * @return an array of key objects, or <code>null</code> if no
149      *          keys have values set
150      * @since 1.3
151      */
152     public Object  [] getKeys() {
153     if (arrayTable == null) {
154         return null;
155     }
156     Object  [] keys = new Object  [arrayTable.size()];
157     arrayTable.getKeys(keys);
158     return keys;
159     }
160 
161     /**
162      * If any <code>PropertyChangeListeners</code> have been registered, the
163      * <code>changeSupport</code> field describes them.
164      */
165     protected SwingPropertyChangeSupport   changeSupport;
166 
167     /**
168      * Supports reporting bound property changes.  This method can be called
169      * when a bound property has changed and it will send the appropriate
170      * <code>PropertyChangeEvent</code> to any registered 
171      * <code>PropertyChangeListeners</code>.
172      */
173     protected void firePropertyChange(String   propertyName, Object   oldValue, Object   newValue) {
174         if (changeSupport == null || 
175         (oldValue != null && newValue != null && oldValue.equals(newValue))) {
176             return;
177         }
178         changeSupport.firePropertyChange(propertyName, oldValue, newValue);
179     }
180 
181 
182     /**
183      * Adds a <code>PropertyChangeListener</code> to the listener list.
184      * The listener is registered for all properties.
185      * <p>
186      * A <code>PropertyChangeEvent</code> will get fired in response to setting
187      * a bound property, e.g. <code>setFont</code>, <code>setBackground</code>,
188      * or <code>setForeground</code>.
189      * Note that if the current component is inheriting its foreground, 
190      * background, or font from its container, then no event will be 
191      * fired in response to a change in the inherited property.
192      *
193      * @param listener  The <code>PropertyChangeListener</code> to be added
194      *
195      * @see Action#addPropertyChangeListener 
196      */
197     public synchronized void addPropertyChangeListener(PropertyChangeListener listener) {
198         if (changeSupport == null) {
199         changeSupport = new SwingPropertyChangeSupport  (this);
200         }
201         changeSupport.addPropertyChangeListener(listener);
202     }
203 
204 
205     /**
206      * Removes a <code>PropertyChangeListener</code> from the listener list.
207      * This removes a <code>PropertyChangeListener</code> that was registered
208      * for all properties.
209      *
210      * @param listener  the <code>PropertyChangeListener</code> to be removed
211      *
212      * @see Action#removePropertyChangeListener 
213      */
214     public synchronized void removePropertyChangeListener(PropertyChangeListener listener) {
215         if (changeSupport == null) {
216             return;
217         }
218         changeSupport.removePropertyChangeListener(listener);
219     }
220 
221 
222     /**
223      * Returns an array of all the <code>PropertyChangeListener</code>s added
224      * to this AbstractAction with addPropertyChangeListener().
225      *
226      * @return all of the <code>PropertyChangeListener</code>s added or an empty
227      *         array if no listeners have been added
228      * @since 1.4
229      */
230     public synchronized PropertyChangeListener[] getPropertyChangeListeners() {
231         if (changeSupport == null) {
232             return new PropertyChangeListener[0];
233         }
234         return changeSupport.getPropertyChangeListeners();
235     }
236 
237 
238     /**
239      * Clones the abstract action. This gives the clone
240      * its own copy of the key/value list,
241      * which is not handled for you by <code>Object.clone()</code>.
242      **/
243 
244     protected Object   clone() throws CloneNotSupportedException   {
245     AbstractAction   newAction = (AbstractAction  )super.clone();
246     synchronized(this) {
247         if (arrayTable != null) {
248         newAction.arrayTable = (ArrayTable  )arrayTable.clone();
249         }
250     }
251     return newAction;
252     }
253 
254     private void writeObject(ObjectOutputStream   s) throws IOException   {
255     // Store the default fields
256         s.defaultWriteObject();
257 
258         // And the keys
259         ArrayTable.writeArrayTable(s, arrayTable);
260     }
261 
262     private void readObject(ObjectInputStream   s) throws ClassNotFoundException  ,
263     IOException   {
264         s.defaultReadObject();
265     for (int counter = s.readInt() - 1; counter >= 0; counter--) {
266         putValue((String  )s.readObject(), s.readObject());
267     }
268     }
269 }
270
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