/* $Id: GenDescendantClasses.java 17846 2010-01-12 19:37:12Z linus $

  *****************************************************************************

  * Copyright (c) 2009 Contributors - see below

  * All rights reserved. This program and the accompanying materials

  * are made available under the terms of the Eclipse Public License v1.0

  * which accompanies this distribution, and is available at

  * http://www.eclipse.org/legal/epl-v10.html

  *

  * Contributors:

  *    tfmorris

  *****************************************************************************

  *

  * Some portions of this file was previously release using the BSD License:

  */

 // Copyright (c) 1996-2006 The Regents of the University of California. All

 // Rights Reserved. Permission to use, copy, modify, and distribute this

 // software and its documentation without fee, and without a written

 // agreement is hereby granted, provided that the above copyright notice

 // and this paragraph appear in all copies.  This software program and

 // documentation are copyrighted by The Regents of the University of

 // California. The software program and documentation are supplied "AS

 // IS", without any accompanying services from The Regents. The Regents

 // does not warrant that the operation of the program will be

 // uninterrupted or error-free. The end-user understands that the program

 // was developed for research purposes and is advised not to rely

 // exclusively on the program for any reason.  IN NO EVENT SHALL THE

 // UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

 // SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,

 // ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF

 // THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF

 // SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY

 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 // PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF

 // CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,

 // UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 package org.argouml.uml;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.Enumeration;

 import java.util.HashSet;

 import java.util.Set;

 import org.argouml.model.Model;

 import org.tigris.gef.util.ChildGenerator;

 /**

  * Utility class to generate the subclasses of a class. It recursively moves

  * down the class hierarchy. But it does that in a safe way that will not hang

  * in case of cyclic inheritance.

  * 

  * @stereotype singleton

  */

 public class GenDescendantClasses implements ChildGenerator {

     private static final GenDescendantClasses SINGLETON =

         new GenDescendantClasses();

     /**

      * @return Returns the sINGLETON.

      */

     public static GenDescendantClasses getSINGLETON() {

         return SINGLETON;

     }

     /*

      * @see org.tigris.gef.util.ChildGenerator#gen(java.lang.Object)

      */

     public Enumeration gen(Object o) {

         Set res = new HashSet();

         if (Model.getFacade().isAGeneralizableElement(o)) {

             Object cls = o;

             accumulateDescendants(cls, res);

         }

         return Collections.enumeration(res);

     }

     /**

      * @param cls the starting class (in fact GeneralizableElement)

      * @param accum the accumulated list of descendants

      */

     private void accumulateDescendants(final Object cls, Collection accum) {

         Collection gens = Model.getFacade().getSpecializations(cls);

         if (gens == null) {

             return;

         }

         for (Object g : gens) {

             Object ge = Model.getFacade().getSpecific(g);

             if (!accum.contains(ge)) {

                 accum.add(ge);

                 accumulateDescendants(cls, accum);

             }

         }

     }

 }