/*

 * Copyright 1997-2004 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing;

import javax.swing.event.*;

import java.io.Serializable;

import java.util.EventListener;

/**

 * The abstract definition for the data model that provides

 * a <code>List</code> with its contents.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author Hans Muller

 */

public abstract class AbstractListModel implements ListModel, Serializable

{

    protected EventListenerList listenerList = new EventListenerList();

    /**

     * Adds a listener to the list that's notified each time a change

     * to the data model occurs.

     *

     * @param l the <code>ListDataListener</code> to be added

     */

    public void addListDataListener(ListDataListener l) {

        listenerList.add(ListDataListener.class, l);

    }

    /**

     * Removes a listener from the list that's notified each time a

     * change to the data model occurs.

     *

     * @param l the <code>ListDataListener</code> to be removed

     */

    public void removeListDataListener(ListDataListener l) {

        listenerList.remove(ListDataListener.class, l);

    }

    /**

     * Returns an array of all the list data listeners

     * registered on this <code>AbstractListModel</code>.

     *

     * @return all of this model's <code>ListDataListener</code>s,

     *         or an empty array if no list data listeners

     *         are currently registered

     *

     * @see #addListDataListener

     * @see #removeListDataListener

     *

     * @since 1.4

     */

    public ListDataListener[] getListDataListeners() {

        return (ListDataListener[])listenerList.getListeners(

                ListDataListener.class);

    }

    /**

     * <code>AbstractListModel</code> subclasses must call this method

     * <b>after</b>

     * one or more elements of the list change.  The changed elements

     * are specified by the closed interval index0, index1 -- the endpoints

     * are included.  Note that

     * index0 need not be less than or equal to index1.

     *

     * @param source the <code>ListModel</code> that changed, typically "this"

     * @param index0 one end of the new interval

     * @param index1 the other end of the new interval

     * @see EventListenerList

     * @see DefaultListModel

     */

    protected void fireContentsChanged(Object source, int index0, int index1)

    {

        Object[] listeners = listenerList.getListenerList();

        ListDataEvent e = null;

        for (int i = listeners.length - 2; i >= 0; i -= 2) {

            if (listeners[i] == ListDataListener.class) {

                if (e == null) {

                    e = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED, index0, index1);

                }

                ((ListDataListener)listeners[i+1]).contentsChanged(e);

            }

        }

    }

    /**

     * <code>AbstractListModel</code> subclasses must call this method

     * <b>after</b>

     * one or more elements are added to the model.  The new elements

     * are specified by a closed interval index0, index1 -- the enpoints

     * are included.  Note that

     * index0 need not be less than or equal to index1.

     *

     * @param source the <code>ListModel</code> that changed, typically "this"

     * @param index0 one end of the new interval

     * @param index1 the other end of the new interval

     * @see EventListenerList

     * @see DefaultListModel

     */

    protected void fireIntervalAdded(Object source, int index0, int index1)

    {

        Object[] listeners = listenerList.getListenerList();

        ListDataEvent e = null;

        for (int i = listeners.length - 2; i >= 0; i -= 2) {

            if (listeners[i] == ListDataListener.class) {

                if (e == null) {

                    e = new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED, index0, index1);

                }

                ((ListDataListener)listeners[i+1]).intervalAdded(e);

            }

        }

    }

    /**

     * <code>AbstractListModel</code> subclasses must call this method

     * <b>after</b> one or more elements are removed from the model.

     * <code>index0</code> and <code>index1</code> are the end points

     * of the interval that's been removed.  Note that <code>index0</code>

     * need not be less than or equal to <code>index1</code>.

     *

     * @param source the <code>ListModel</code> that changed, typically "this"

     * @param index0 one end of the removed interval,

     *               including <code>index0</code>

     * @param index1 the other end of the removed interval,

     *               including <code>index1</code>

     * @see EventListenerList

     * @see DefaultListModel

     */

    protected void fireIntervalRemoved(Object source, int index0, int index1)

    {

        Object[] listeners = listenerList.getListenerList();

        ListDataEvent e = null;

        for (int i = listeners.length - 2; i >= 0; i -= 2) {

            if (listeners[i] == ListDataListener.class) {

                if (e == null) {

                    e = new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED, index0, index1);

                }

                ((ListDataListener)listeners[i+1]).intervalRemoved(e);

            }

        }

    }

    /**

     * Returns an array of all the objects currently registered as

     * <code><em>Foo</em>Listener</code>s

     * upon this model.

     * <code><em>Foo</em>Listener</code>s

     * are registered using the <code>add<em>Foo</em>Listener</code> method.

     * <p>

     * You can specify the <code>listenerType</code> argument

     * with a class literal, such as <code><em>Foo</em>Listener.class</code>.

     * For example, you can query a list model

     * <code>m</code>

     * for its list data listeners

     * with the following code:

     *

     * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre>

     *

     * If no such listeners exist,

     * this method returns an empty array.

     *

     * @param listenerType  the type of listeners requested;

     *          this parameter should specify an interface

     *          that descends from <code>java.util.EventListener</code>

     * @return an array of all objects registered as

     *          <code><em>Foo</em>Listener</code>s

     *          on this model,

     *          or an empty array if no such

     *          listeners have been added

     * @exception ClassCastException if <code>listenerType</code> doesn't

     *          specify a class or interface that implements

     *          <code>java.util.EventListener</code>

     *

     * @see #getListDataListeners

     *

     * @since 1.3

     */

    public <T extends EventListener> T[] getListeners(Class<T> listenerType) {

        return listenerList.getListeners(listenerType);

    }

}