001    /* AbstractSpinnerModel.java --
002       Copyright (C) 2004, 2006, Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing;
040    
041    import java.util.EventListener;
042    
043    import javax.swing.event.ChangeEvent;
044    import javax.swing.event.ChangeListener;
045    import 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     */
055    public 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    }