/*

 * Copyright 1997-2001 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.ListDataListener;

/**

 * This interface defines the methods components like JList use

 * to get the value of each cell in a list and the length of the list.

 * Logically the model is a vector, indices vary from 0 to

 * ListDataModel.getSize() - 1.  Any change to the contents or

 * length of the data model must be reported to all of the

 * ListDataListeners.

 *

 * @author Hans Muller

 * @see JList

 */

public interface ListModel

{

  /**

   * Returns the length of the list.

   * @return the length of the list

   */

  int getSize();

  /**

   * Returns the value at the specified index.

   * @param index the requested index

   * @return the value at <code>index</code>

   */

  Object getElementAt(int index);

  /**

   * 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

   */

  void addListDataListener(ListDataListener 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

   */

  void removeListDataListener(ListDataListener l);

}