001/* AbstractSpinnerModel.java --
002   Copyright (C) 2004, 2006, Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing;
040
041import java.util.EventListener;
042
043import javax.swing.event.ChangeEvent;
044import javax.swing.event.ChangeListener;
045import javax.swing.event.EventListenerList;
046
047/**
048 * Provides standard implementations for some of the methods in
049 * {@link SpinnerModel}.
050 *
051 * @since 1.4
052 *
053 * @author Ka-Hing Cheung
054 */
055public abstract class AbstractSpinnerModel implements SpinnerModel
056{
057  private ChangeEvent changeEvent = new ChangeEvent(this);
058
059  /** Stores the listeners registered with the model. */
060  protected EventListenerList listenerList = new EventListenerList();
061
062  /**
063   * Creates an <code>AbstractSpinnerModel</code>.
064   */
065  public AbstractSpinnerModel()
066  {
067    // Nothing to do here.
068  }
069
070  /**
071   * Registers a <code>ChangeListener</code> with the model so that it will
072   * receive {@link ChangeEvent} notifications when the model changes.
073   *
074   * @param listener the listener to add (<code>null</code> is ignored).
075   */
076  public void addChangeListener(ChangeListener listener)
077  {
078    listenerList.add(ChangeListener.class, listener);
079  }
080
081  /**
082   * Gets all the listeners that are of a particular type.
083   *
084   * @param c the type of listener
085   * @return the listeners that are of the specific type
086   */
087  public <T extends EventListener> T[] getListeners(Class<T> c)
088  {
089    return listenerList.getListeners(c);
090  }
091
092  /**
093   * Gets all the <code>ChangeListener</code>s.
094   *
095   * @return all the <code>ChangeListener</code>s
096   */
097  public ChangeListener[] getChangeListeners()
098  {
099    return (ChangeListener[]) listenerList.getListeners(ChangeListener.class);
100  }
101
102  /**
103   * Remove a particular listener.
104   *
105   * @param listener the listener to remove
106   */
107  public void removeChangeListener(ChangeListener listener)
108  {
109    listenerList.remove(ChangeListener.class, listener);
110  }
111
112  /**
113   * Fires a <code>ChangeEvent</code> to all the <code>ChangeListener</code>s
114   * added to this model
115   */
116  protected void fireStateChanged()
117  {
118    ChangeListener[] listeners = getChangeListeners();
119
120    for (int i = 0; i < listeners.length; ++i)
121      listeners[i].stateChanged(changeEvent);
122  }
123}