001    /* AbstractListModel.java --
002       Copyright (C) 2002, 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.io.Serializable;
042    import java.util.EventListener;
043    
044    import javax.swing.event.EventListenerList;
045    import javax.swing.event.ListDataEvent;
046    import javax.swing.event.ListDataListener;
047    
048    /**
049     * Provides standard implementations of some methods in {@link ListModel}.
050     *
051     * @author Ronald Veldema
052     * @author Andrew Selkirk
053     */
054    public abstract class AbstractListModel implements ListModel, Serializable
055    {
056      private static final long serialVersionUID = -3285184064379168730L;
057    
058      /** List of ListDataListeners called for each change to the list. */
059      protected EventListenerList listenerList;
060    
061      /**
062       * Creates a new model instance - initialises the event listener list.
063       */
064      public AbstractListModel()
065      {
066        listenerList = new EventListenerList();
067      }
068    
069      /**
070       * Add a listener object to this model. The listener will be called
071       * any time the set of elements in the model is changed.
072       *
073       * @param listener The listener to add
074       */
075      public void addListDataListener(ListDataListener listener)
076      {
077        listenerList.add(ListDataListener.class, listener);
078      }
079    
080      /**
081       * Add a listener object to this model. The listener will no longer be
082       * called when the set of elements in the model is changed.
083       *
084       * @param listener The listener to remove
085       */
086      public void removeListDataListener(ListDataListener listener)
087      {
088        listenerList.remove(ListDataListener.class, listener);
089      }
090    
091      /**
092       * Call {@link ListDataListener#contentsChanged} on each element of the
093       * {@link #listenerList} which is a {@link ListDataListener}. The event
094       * fired has type {@link ListDataEvent#CONTENTS_CHANGED} and represents a
095       * change to the data elements in the range [startIndex, endIndex]
096       * inclusive.
097       *
098       * @param source The source of the change, typically <code>this</code>
099       * @param startIndex The index of the first element which changed
100       * @param endIndex The index of the last element which changed
101       */
102      protected void fireContentsChanged(Object source, int startIndex,
103                                         int endIndex)
104      {
105        ListDataEvent event = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED,
106                                                startIndex, endIndex);
107        ListDataListener[] listeners = getListDataListeners();
108    
109        for (int index = 0; index < listeners.length; index++)
110          listeners[index].contentsChanged(event);
111      }
112    
113      /**
114       * Call {@link ListDataListener#intervalAdded} on each element of the
115       * {@link #listenerList} which is a {@link ListDataListener}. The event
116       * fired has type {@link ListDataEvent#INTERVAL_ADDED} and represents an
117       * addition of the data elements in the range [startIndex, endIndex]
118       * inclusive.
119       *
120       * @param source The source of the change, typically <code>this</code>
121       * @param startIndex The index of the first new element
122       * @param endIndex The index of the last new element
123       */
124      protected void fireIntervalAdded(Object source, int startIndex, int endIndex)
125      {
126        ListDataEvent event =
127          new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED,
128                            startIndex, endIndex);
129        ListDataListener[] listeners = getListDataListeners();
130    
131        for (int index = 0; index < listeners.length; index++)
132          listeners[index].intervalAdded(event);
133      }
134    
135      /**
136       * Call {@link ListDataListener#intervalRemoved} on each element of the
137       * {@link #listenerList} which is a {@link ListDataListener}. The event
138       * fired has type {@link ListDataEvent#INTERVAL_REMOVED} and represents a
139       * removal of the data elements in the range [startIndex, endIndex]
140       * inclusive.
141       *
142       * @param source The source of the change, typically <code>this</code>
143       * @param startIndex The index of the first element removed
144       * @param endIndex The index of the last element removed
145       */
146      protected void fireIntervalRemoved(Object source, int startIndex,
147                                         int endIndex)
148      {
149        ListDataEvent event =
150          new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED,
151                            startIndex, endIndex);
152        ListDataListener[] listeners = getListDataListeners();
153    
154        for (int index = 0; index < listeners.length; index++)
155          listeners[index].intervalRemoved(event);
156      }
157    
158      /**
159       * Return the subset of {@link EventListener} objects found in this
160       * object's {@link #listenerList} which are elements of the specified
161       * type.
162       *
163       * @param listenerType The type of listeners to select
164       *
165       * @return The set of listeners of the specified type
166       */
167      public <T extends EventListener> T[] getListeners(Class<T> listenerType)
168      {
169        return listenerList.getListeners(listenerType);
170      }
171    
172      /**
173       * A synonym for <code>getListeners(ListDataListener.class)</code>.
174       *
175       * @return The set of ListDataListeners found in the {@link #listenerList}
176       */
177      public ListDataListener[] getListDataListeners()
178      {
179        return (ListDataListener[]) getListeners(ListDataListener.class);
180      }
181    }