/*
 *
 * Copyright (C) 2007-2015 Licensed to the Comunes Association (CA) under 
 * one or more contributor license agreements (see COPYRIGHT for details).
 * The CA licenses this file to you under the GNU Affero General Public 
 * License version 3, (the "License"); you may not use this file except in 
 * compliance with the License. This file is part of kune.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
package cc.kune.common.client.actions;

import java.util.HashMap;

// TODO: Auto-generated Javadoc
/**
 * A base class for implementing the {@link Action} interface.
 * 
 * @author Andrew Selkirk
 * @author Adapted version for GWT (C) The kune development team
 */
public class ChangeableObject {

  /**
   * Provides support for property change event notification.
   */
  protected PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
  
  /** store. */
  protected HashMap<String, Object> store = new HashMap<String, Object>();

  /**
   * Registers a listener to receive {@link PropertyChangeEvent} notifications
   * from this action.
   * 
   * @param listener
   *          the listener.
   * 
   * @see #removePropertyChangeListener(PropertyChangeListener)
   */
  public void addPropertyChangeListener(final PropertyChangeListener listener) {
    changeSupport.addPropertyChangeListener(listener);
  }

  /**
   * Returns an array of the keys for the property values that have been defined
   * via the {@link #putValue(String, Object)} method (or the class
   * constructor).
   * 
   * @return An array of keys.
   */
  public Object[] getKeys() {
    return store.keySet().toArray();
  }

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

  /**
   * 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.
   * 
   * @see #putValue(String, Object)
   */
  public Object getValue(final String key) {
    return store.get(key);
  }

  /**
   * Sets the value associated with the specified key and sends a.
   *
   * @param key the key (not <code>null</code>).
   * @param value the value (<code>null</code> permitted).
   * {@link java.beans.PropertyChangeEvent} to all registered listeners.
   * 
   * Any existing value associated with the key will be overwritten.
   */
  public void putValue(final String key, final Object value) {
    final Object old = getValue(key);
    if ((old == null && value != null) || (old != null && !old.equals(value))) {
      store.put(key, value);
      firePropertyChange(key, old, value);
    }
  }

  /**
   * Deregisters a listener so that it no longer receives.
   *
   * @param listener the listener.
   * {@link PropertyChangeEvent} notifications from this action.
   * @see #addPropertyChangeListener(PropertyChangeListener)
   */
  public void removePropertyChangeListener(final PropertyChangeListener listener) {
    changeSupport.removePropertyChangeListener(listener);
  }

  /**
   * Sends a {@link PropertyChangeEvent} for the named property to all
   * registered listeners. This private method is called by the
   *
   * @param propertyName the property name.
   * @param oldValue the old value of the property.
   * @param newValue the new value of the property.
   * {@link #setEnabled(boolean)} method.
   */
  protected void firePropertyChange(final String propertyName, final boolean oldValue,
      final boolean newValue) {
    changeSupport.firePropertyChange(propertyName, oldValue, newValue);
  }

  /**
   * Sends a {@link PropertyChangeEvent} for the named property to all
   * registered listeners.
   * 
   * @param propertyName
   *          the property name.
   * @param oldValue
   *          the old value of the property.
   * @param newValue
   *          the new value of the property.
   */
  protected void firePropertyChange(final String propertyName, final Object oldValue,
      final Object newValue) {
    changeSupport.firePropertyChange(propertyName, oldValue, newValue);
  }

}