libjava/classpath/javax/swing/AbstractAction.java

/* AbstractAction.java --
   Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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package javax.swing;

import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.HashMap;

import javax.swing.event.SwingPropertyChangeSupport;

/**
 * A base class for implementing the {@link Action} interface.
 * 
 * @author Andrew Selkirk
 */
public abstract class AbstractAction
  implements Action, Cloneable, Serializable
{
  private static final long serialVersionUID = -6803159439231523484L;

  /**
   * A flag that indicates whether or not the action is enabled.
   */
  protected boolean enabled = true;
  
  /**
   * Provides support for property change event notification. 
   */
  protected SwingPropertyChangeSupport changeSupport =
    new SwingPropertyChangeSupport(this);

  /**
   * store
   */
  private transient HashMap store = new HashMap();

  /**
   * Creates a new action with an empty string for the name.  All other 
   * properties are initialised to <code>null</code>
   */
  public AbstractAction()
  {
    this(""); // TODO: default name
  }

  /**
   * Creates a new action with the specified name.  All other properties are
   * initialised to <code>null</code>.
   *
   * @param name  the name (<code>null</code> permitted).
   */
  public AbstractAction(String name)
  {
    this(name, null); // TODO: default icon??
  }

  /**
   * Creates a new action with the specified name and icon.  All other 
   * properties are initialised to <code>null</code>.
   *
   * @param name  the name (<code>null</code> permitted).
   * @param icon  the icon (<code>null</code> permitted).
   */
  public AbstractAction(String name, Icon icon)
  {
    putValue(NAME, name);
    putValue(SMALL_ICON, icon);
  }

  /**
   * readObject
   *
   * @param stream the stream to read from
   *
   * @exception ClassNotFoundException TODO
   * @exception IOException if an error occurs
   */
  private void readObject(ObjectInputStream stream)
    throws ClassNotFoundException, IOException
  {
    // TODO
  }

  /**
   * writeObject
   *
   * @param stream the stream to write to
   *
   * @exception IOException if an error occurs
   */
  private void writeObject(ObjectOutputStream stream) throws IOException
  {
    // TODO
  }

  /**
   * clone
   *
   * @return Object
   *
   * @exception CloneNotSupportedException TODO
   */
  protected Object clone() throws CloneNotSupportedException
  {
    AbstractAction copy = (AbstractAction) super.clone();
    copy.store = (HashMap) store.clone();
    return copy;
  }

  /**
   * Returns the value associated with the specified key.
   * 
   * @param key  the key (not <code>null</code>).
   * 
   * @return The value associated with the specified key, or 
   *         <code>null</code> if the key is not found.
   */
  public Object getValue(String key)
  {
    return store.get(key);
  }

  /**
   * Sets the value associated with the specified key and sends a 
   * {@link java.beans.PropertyChangeEvent} to all registered listeners.  
   * The standard keys are: {@link #NAME}, {@link #SHORT_DESCRIPTION}, 
   * {@link #LONG_DESCRIPTION}, {@link #SMALL_ICON}, 
   * {@link #ACTION_COMMAND_KEY}, {@link #ACCELERATOR_KEY} and 
   * {@link #MNEMONIC_KEY}. Any existing value associated with the key will be 
   * overwritten.
   * 
   * @param key  the key (not <code>null</code>).
   * @param value  the value (<code>null</code> permitted).
   */
  public void putValue(String key, Object value)
  {
    Object old = getValue(key);
    if (old != value)
    {
      store.put(key, value);
      firePropertyChange(key, old, value);
    }
  }

  /**
   * Returns the flag that indicates whether or not the action is enabled.
   *
   * @return The flag.
   */
  public boolean isEnabled()
  {
    return enabled;
  }

  /**
   * Sets the flag that indicates whether or not the action is enabled and, if
   * the value of the flag changed from the previous setting, sends a 
   * {@link java.beans.PropertyChangeEvent} to all registered listeners.
   *
   * @param enabled  the new flag value.
   */
  public void setEnabled(boolean enabled)
  {
    if (enabled != this.enabled)
    {
      this.enabled = enabled;
      firePropertyChange("enabled", !this.enabled, this.enabled);
    }
  }

  /**
   * getKeys
   * @returns Object[]
   */
  public Object[] getKeys()
  {
    return store.keySet().toArray();
  }

  /**
   * This method fires a PropertyChangeEvent given the propertyName 
   * and the old and new values.
   *
   * @param propertyName The property that changed.
   * @param oldValue The old value of the property.
   * @param newValue The new value of the property.
   */
  protected void firePropertyChange(String propertyName, Object oldValue,
                                    Object newValue)
  {
    changeSupport.firePropertyChange(propertyName, oldValue, newValue);
  }
  
  /**
   * This convenience method fires a PropertyChangeEvent given 
   * the propertyName and the old and new values.
   *
   * @param propertyName The property that changed.
   * @param oldValue The old value of the property.
   * @param newValue The new value of the property.
   */
  private void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
  {
    changeSupport.firePropertyChange(propertyName, oldValue, newValue);
  }

  /**
   * addPropertyChangeListener
   *
   * @param listener the listener to add
   */
  public void addPropertyChangeListener(PropertyChangeListener listener)
  {
    changeSupport.addPropertyChangeListener(listener);
  }

  /**
   * removePropertyChangeListener
   *
   * @param listener the listener to remove
   */
  public void removePropertyChangeListener(PropertyChangeListener listener)
  {
    changeSupport.removePropertyChangeListener(listener);
  }

  /**
   * Returns all registered listeners.
   *
   * @return array of listeners.
   * 
   * @since 1.4
   */
  public PropertyChangeListener[] getPropertyChangeListeners()
  {
    return changeSupport.getPropertyChangeListeners();
  }
}