// $Id: GenCompositeClasses.java,v 1.14 2004/08/29 07:47:29 mvw Exp $
// Copyright (c) 1996-2004 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
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// does not warrant that the operation of the program will be
// uninterrupted or error-free. The end-user understands that the program
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// UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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package org.argouml.uml;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;
import org.argouml.model.ModelFacade;
import org.tigris.gef.util.ChildGenerator;

/** Utility class to generate a list of the children of a class.  In this case
 *  the "children" of a class are the other classes that are
 *  associated with the parent class, and that MAssociation has a
 *  COMPOSITE end at the parent.  This is used in one of the
 *  Perspectives. 
 *  @stereotype singleton
 */
public class GenCompositeClasses implements ChildGenerator {
    /**
     * This SINGLETON is used in CrCircularComposition.
     * 
     */
    private static final GenCompositeClasses SINGLETON = 
        new GenCompositeClasses();

    /**
     * @return Returns the sINGLETON.
     */
    public static GenCompositeClasses getSINGLETON() {
        return SINGLETON;
    }
    /**
     * @see org.tigris.gef.util.ChildGenerator#gen(java.lang.Object)
     */
    public Enumeration gen(Object o) {
	Vector res = new Vector();
	if (!(ModelFacade.isAClassifier(o))) return res.elements();
	Object cls = /*(MClassifier)*/ o;
	Vector ends = new Vector(ModelFacade.getAssociationEnds(cls));
	if (ends == null) return res.elements();
	Iterator assocEnds = ends.iterator();
	while (assocEnds.hasNext()) {
	    Object ae = /*(MAssociationEnd)*/ assocEnds.next();
	    if (ModelFacade.COMPOSITE_AGGREGATIONKIND.equals(
	            ModelFacade.getAggregation(ae))) {
		Object asc = ModelFacade.getAssociation(ae);
		ArrayList conn = new ArrayList(ModelFacade.getConnections(asc));
		if (conn == null || conn.size() != 2) continue;
		Object otherEnd = (ae == conn.get(0)) 
		    ? conn.get(1) : conn.get(0);
		res.add(ModelFacade.getType(otherEnd));
	    }
	}
	return res.elements();
    }
} /* end class GenCompositeClasses */