/* AbstractListModel.java --
   Copyright (C) 2002, 2004, 2006, 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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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
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this exception to your version of the library, but you are not
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package javax.swing;

import java.io.Serializable;
import java.util.EventListener;

import javax.swing.event.EventListenerList;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;

/**
 * Provides standard implementations of some methods in {@link ListModel}.
 *
 * @author Ronald Veldema
 * @author Andrew Selkirk
 */
public abstract class AbstractListModel implements ListModel, Serializable
{
  private static final long serialVersionUID = -3285184064379168730L;

  /** List of ListDataListeners called for each change to the list. */
  protected EventListenerList listenerList;

  /**
   * Creates a new model instance - initialises the event listener list.
   */
  public AbstractListModel()
  {
    listenerList = new EventListenerList();
  }

  /**
   * Add a listener object to this model. The listener will be called
   * any time the set of elements in the model is changed.
   *
   * @param listener The listener to add
   */
  public void addListDataListener(ListDataListener listener)
  {
    listenerList.add(ListDataListener.class, listener);
  }

  /**
   * Add a listener object to this model. The listener will no longer be
   * called when the set of elements in the model is changed.
   *
   * @param listener The listener to remove
   */
  public void removeListDataListener(ListDataListener listener)
  {
    listenerList.remove(ListDataListener.class, listener);
  }

  /**
   * Call {@link ListDataListener#contentsChanged} on each element of the
   * {@link #listenerList} which is a {@link ListDataListener}. The event
   * fired has type {@link ListDataEvent#CONTENTS_CHANGED} and represents a
   * change to the data elements in the range [startIndex, endIndex]
   * inclusive.
   *
   * @param source The source of the change, typically <code>this</code>
   * @param startIndex The index of the first element which changed
   * @param endIndex The index of the last element which changed
   */
  protected void fireContentsChanged(Object source, int startIndex,
                                     int endIndex)
  {
    ListDataEvent event = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED,
                                            startIndex, endIndex);
    ListDataListener[] listeners = getListDataListeners();

    for (int index = 0; index < listeners.length; index++)
      listeners[index].contentsChanged(event);
  }

  /**
   * Call {@link ListDataListener#intervalAdded} on each element of the
   * {@link #listenerList} which is a {@link ListDataListener}. The event
   * fired has type {@link ListDataEvent#INTERVAL_ADDED} and represents an
   * addition of the data elements in the range [startIndex, endIndex]
   * inclusive.
   *
   * @param source The source of the change, typically <code>this</code>
   * @param startIndex The index of the first new element
   * @param endIndex The index of the last new element
   */
  protected void fireIntervalAdded(Object source, int startIndex, int endIndex)
  {
    ListDataEvent event =
      new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED,
			startIndex, endIndex);
    ListDataListener[] listeners = getListDataListeners();

    for (int index = 0; index < listeners.length; index++)
      listeners[index].intervalAdded(event);
  }

  /**
   * Call {@link ListDataListener#intervalRemoved} on each element of the
   * {@link #listenerList} which is a {@link ListDataListener}. The event
   * fired has type {@link ListDataEvent#INTERVAL_REMOVED} and represents a
   * removal of the data elements in the range [startIndex, endIndex]
   * inclusive.
   *
   * @param source The source of the change, typically <code>this</code>
   * @param startIndex The index of the first element removed
   * @param endIndex The index of the last element removed
   */
  protected void fireIntervalRemoved(Object source, int startIndex,
                                     int endIndex)
  {
    ListDataEvent event =
      new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED,
			startIndex, endIndex);
    ListDataListener[] listeners = getListDataListeners();

    for (int index = 0; index < listeners.length; index++)
      listeners[index].intervalRemoved(event);
  }

  /**
   * Return the subset of {@link EventListener} objects found in this
   * object's {@link #listenerList} which are elements of the specified
   * type.
   *
   * @param listenerType The type of listeners to select
   *
   * @return The set of listeners of the specified type
   */
  public EventListener[] getListeners(Class listenerType)
  {
    return listenerList.getListeners(listenerType);
  }

  /**
   * A synonym for <code>getListeners(ListDataListener.class)</code>.
   *
   * @return The set of ListDataListeners found in the {@link #listenerList}
   */
  public ListDataListener[] getListDataListeners()
  {
    return (ListDataListener[]) getListeners(ListDataListener.class);
  }
}