libjava/classpath/javax/swing/AbstractAction.java

   1 /* AbstractAction.java --
   2    Copyright (C) 2002, 2004, 2005, 2006  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.swing;
  40
  41 import java.beans.PropertyChangeEvent;
  42 import java.beans.PropertyChangeListener;
  43 import java.io.IOException;
  44 import java.io.ObjectInputStream;
  45 import java.io.ObjectOutputStream;
  46 import java.io.Serializable;
  47 import java.util.HashMap;
  48
  49 import javax.swing.event.SwingPropertyChangeSupport;
  50
  51 /**
  52  * A base class for implementing the {@link Action} interface.
  53  *
  54  * @author Andrew Selkirk
  55  */
  56 public abstract class AbstractAction
  57   implements Action, Cloneable, Serializable
  58 {
  59   private static final long serialVersionUID = -6803159439231523484L;
  60
  61   /**
  62    * A flag that indicates whether or not the action is enabled.
  63    */
  64   protected boolean enabled = true;
  65
  66   /**
  67    * Provides support for property change event notification.
  68    */
  69   protected SwingPropertyChangeSupport changeSupport =
  70     new SwingPropertyChangeSupport(this);
  71
  72   /**
  73    * store
  74    */
  75   private transient HashMap store = new HashMap();
  76
  77   /**
  78    * Creates a new action with no properties set.
  79    */
  80   public AbstractAction()
  81   {
  82     // Nothing to do.
  83   }
  84
  85   /**
  86    * Creates a new action with the specified name.  The name is stored as a
  87    * property with the key {@link Action#NAME}, and no other properties are
  88    * initialised.
  89    *
  90    * @param name  the name (<code>null</code> permitted).
  91    */
  92   public AbstractAction(String name)
  93   {
  94     putValue(NAME, name);
  95   }
  96
  97   /**
  98    * Creates a new action with the specified name and icon.  The name is stored
  99    * as a property with the key {@link Action#NAME}, the icon is stored as a
 100    * property with the key {@link Action#SMALL_ICON}, and no other properties
 101    * are initialised.
 102    *
 103    * @param name  the name (<code>null</code> permitted).
 104    * @param icon  the icon (<code>null</code> permitted).
 105    */
 106   public AbstractAction(String name, Icon icon)
 107   {
 108     putValue(NAME, name);
 109     putValue(SMALL_ICON, icon);
 110   }
 111
 112   /**
 113    * readObject
 114    *
 115    * @param stream the stream to read from
 116    *
 117    * @exception ClassNotFoundException TODO
 118    * @exception IOException if an error occurs
 119    */
 120   private void readObject(ObjectInputStream stream)
 121     throws ClassNotFoundException, IOException
 122   {
 123     // TODO
 124   }
 125
 126   /**
 127    * writeObject
 128    *
 129    * @param stream the stream to write to
 130    *
 131    * @exception IOException if an error occurs
 132    */
 133   private void writeObject(ObjectOutputStream stream) throws IOException
 134   {
 135     // TODO
 136   }
 137
 138   /**
 139    * Returns a clone of the action.
 140    *
 141    * @return A clone of the action.
 142    *
 143    * @exception CloneNotSupportedException if there is a problem cloning the
 144    *            action.
 145    */
 146   protected Object clone() throws CloneNotSupportedException
 147   {
 148     AbstractAction copy = (AbstractAction) super.clone();
 149     copy.store = (HashMap) store.clone();
 150     return copy;
 151   }
 152
 153   /**
 154    * Returns the value associated with the specified key.
 155    *
 156    * @param key  the key (not <code>null</code>).
 157    *
 158    * @return The value associated with the specified key, or
 159    *         <code>null</code> if the key is not found.
 160    *
 161    * @see #putValue(String, Object)
 162    */
 163   public Object getValue(String key)
 164   {
 165     return store.get(key);
 166   }
 167
 168   /**
 169    * Sets the value associated with the specified key and sends a
 170    * {@link java.beans.PropertyChangeEvent} to all registered listeners.
 171    * The standard keys are:
 172    * <ul>
 173    * <li>{@link #NAME}</li>
 174    * <li>{@link #SHORT_DESCRIPTION}</li>
 175    * <li>{@link #LONG_DESCRIPTION}</li>
 176    * <li>{@link #SMALL_ICON}</li>
 177    * <li>{@link #ACTION_COMMAND_KEY}</li>
 178    * <li>{@link #ACCELERATOR_KEY}</li>
 179    * <li>{@link #MNEMONIC_KEY}</li>
 180    * </ul>
 181    * Any existing value associated with the key will be overwritten.
 182    *
 183    * @param key  the key (not <code>null</code>).
 184    * @param value  the value (<code>null</code> permitted).
 185    */
 186   public void putValue(String key, Object value)
 187   {
 188     Object old = getValue(key);
 189     if ((old == null && value != null) || (old != null && !old.equals(value)))
 190     {
 191       store.put(key, value);
 192       firePropertyChange(key, old, value);
 193     }
 194   }
 195
 196   /**
 197    * Returns the flag that indicates whether or not the action is enabled.
 198    *
 199    * @return The flag.
 200    *
 201    * @see #setEnabled(boolean)
 202    */
 203   public boolean isEnabled()
 204   {
 205     return enabled;
 206   }
 207
 208   /**
 209    * Sets the flag that indicates whether or not the action is enabled and, if
 210    * the value of the flag changed from the previous setting, sends a
 211    * {@link java.beans.PropertyChangeEvent} to all registered listeners (using
 212    * the property name 'enabled').
 213    *
 214    * @param enabled  the new flag value.
 215    *
 216    * @see #isEnabled()
 217    */
 218   public void setEnabled(boolean enabled)
 219   {
 220     if (enabled != this.enabled)
 221     {
 222       this.enabled = enabled;
 223       firePropertyChange("enabled", !this.enabled, this.enabled);
 224     }
 225   }
 226
 227   /**
 228    * Returns an array of the keys for the property values that have been
 229    * defined via the {@link #putValue(String, Object)} method (or the class
 230    * constructor).
 231    *
 232    * @return An array of keys.
 233    */
 234   public Object[] getKeys()
 235   {
 236     return store.keySet().toArray();
 237   }
 238
 239   /**
 240    * Sends a {@link PropertyChangeEvent} for the named property to all
 241    * registered listeners.
 242    *
 243    * @param propertyName  the property name.
 244    * @param oldValue  the old value of the property.
 245    * @param newValue  the new value of the property.
 246    */
 247   protected void firePropertyChange(String propertyName, Object oldValue,
 248                                     Object newValue)
 249   {
 250     changeSupport.firePropertyChange(propertyName, oldValue, newValue);
 251   }
 252
 253   /**
 254    * Sends a {@link PropertyChangeEvent} for the named property to all
 255    * registered listeners.  This private method is called by the
 256    * {@link #setEnabled(boolean)} method.
 257    *
 258    * @param propertyName  the property name.
 259    * @param oldValue  the old value of the property.
 260    * @param newValue  the new value of the property.
 261    */
 262   private void firePropertyChange(String propertyName, boolean oldValue,
 263                                   boolean newValue)
 264   {
 265     changeSupport.firePropertyChange(propertyName, oldValue, newValue);
 266   }
 267
 268   /**
 269    * Registers a listener to receive {@link PropertyChangeEvent} notifications
 270    * from this action.
 271    *
 272    * @param listener the listener.
 273    *
 274    * @see #removePropertyChangeListener(PropertyChangeListener)
 275    */
 276   public void addPropertyChangeListener(PropertyChangeListener listener)
 277   {
 278     changeSupport.addPropertyChangeListener(listener);
 279   }
 280
 281   /**
 282    * Deregisters a listener so that it no longer receives
 283    * {@link PropertyChangeEvent} notifications from this action.
 284    *
 285    * @param listener the listener.
 286    *
 287    * @see #addPropertyChangeListener(PropertyChangeListener)
 288    */
 289   public void removePropertyChangeListener(PropertyChangeListener listener)
 290   {
 291     changeSupport.removePropertyChangeListener(listener);
 292   }
 293
 294   /**
 295    * Returns all registered listeners.
 296    *
 297    * @return An array of listeners.
 298    *
 299    * @since 1.4
 300    */
 301   public PropertyChangeListener[] getPropertyChangeListeners()
 302   {
 303     return changeSupport.getPropertyChangeListeners();
 304   }
 305 }