/**
 * Redistribution and use of this software and associated documentation ("Software"), with or
 * without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
 * must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
 * without prior written permission of Intalio, Inc. For written permission, please contact
 * info@exolab.org.
 *
 * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
 * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
 * Intalio, Inc.
 *
 * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2002 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id$
 */


package org.exolab.castor.mapping;


import java.util.Enumeration;


/**
 * A Map handler for adding and retreiving key-value pairs from A map. A map handler is instantiated
 * only once, must be thread safe and not use any synchronization.
 *
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2004-02-13 14:34:10 -0700 (Fri, 13 Feb 2004) $
 */
public interface MapHandler {

  /**
   * Creates a new Instance of the map represented by this MapHandler.
   *
   * @return the new map.
   */
  public Object create();

  /**
   * Adds the given key-value pair to the map. Keys must be unique. Adding a key-value pair to the
   * map, when an existing association for that key already exists will cause the existing
   * association to be overwritten.
   * 
   * The map is provided as a parameter and is returned as the return value if the returned map is a
   * different object. That way the handler can create a new map if necessary.
   *
   * @param map the map, null if no map has been created yet.
   * @param key the key for the object.
   * @param object the object to add to the map.
   * @return The map with the new object if a different instance than the <tt>map</tt> parameter,
   *         null otherwise
   * @throws ClassCastException The MapHandler does not support maps of the given type.
   */
  public Object put(Object map, Object key, Object object) throws ClassCastException;


  /**
   * Returns an enumeration of all the objects in the Map.
   *
   * @param map The map instance for which to return the enumeration of elements for.
   * @return An enumeration of all the elements in the Map.
   * @throws ClassCastException The MapHandler does not support collections of this type
   */
  public Enumeration elements(Object map) throws ClassCastException;

  /**
   * Returns an enumeration of all the keys in the Map.
   *
   * @param map The map instance for which to return the enumeration of keys.
   * @return An enumeration of all the keys in the Map.
   * @throws ClassCastException The MapHandler does not support collections of this type
   */
  public Enumeration keys(Object map) throws ClassCastException;


  /**
   * Returns the number of elements (key-value) in the map.
   *
   * @param map the map.
   * @return Number of key-value associations in the Map
   * @throws ClassCastException The MapHandler does not support collections of the given type.
   */
  public int size(Object map) throws ClassCastException;


  /**
   * Clears the map of all key-value pairs.
   *
   * @param map the map to clear.
   * @throws ClassCastException The MapHandler does not support collections of the given type.
   */
  public void clear(Object map) throws ClassCastException;

  /**
   * Returns the object associated with the given key.
   *
   * @param map the map to return the object from.
   * @param key the key for the object.
   * @return the object associated with the given key, or null if no association was found in the
   *         given map.
   * @throws ClassCastException The MapHandler does not support maps of the given type.
   */
  public Object get(Object map, Object key) throws ClassCastException;

} // -- MapHandler


