// $Id: CrSubclassReference.java,v 1.12 2004/09/21 19:03:26 mvw Exp $
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// File: CrSubclassReference.javoa
// Classes: CrSubclassReference
// Original Author: jrobbins@ics.uci.edu
// $Id: CrSubclassReference.java,v 1.12 2004/09/21 19:03:26 mvw Exp $

package org.argouml.uml.cognitive.critics;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import org.argouml.cognitive.Designer;
import org.argouml.cognitive.ToDoItem;
import org.argouml.uml.cognitive.UMLToDoItem;
import org.argouml.cognitive.critics.Critic;
import org.argouml.model.ModelFacade;
import org.argouml.uml.GenDescendantClasses;

import org.tigris.gef.util.VectorSet;
/** A critic to detect when a class can never have instances (of
 *  itself of any subclasses). */

public class CrSubclassReference extends CrUML {

    /**
     * The constructor.
     * 
     */
    public CrSubclassReference() {
	setHeadline("Remove Reference to Specific Subclass");
	addSupportedDecision(CrUML.DEC_RELATIONSHIPS);
	addSupportedDecision(CrUML.DEC_PLANNED_EXTENSIONS);
	setKnowledgeTypes(Critic.KT_SEMANTICS);
	addTrigger("specialization");
	addTrigger("associationEnd");
    }

    /**
     * @see org.argouml.uml.cognitive.critics.CrUML#predicate2(
     * java.lang.Object, org.argouml.cognitive.Designer)
     */
    public boolean predicate2(Object dm, Designer dsgr) {
	if (!(ModelFacade.isAClass(dm))) return NO_PROBLEM;
	Object cls = /*(MClass)*/ dm;
	VectorSet offs = computeOffenders(cls);
	if (offs != null) return PROBLEM_FOUND;
	return NO_PROBLEM;
    }

    /**
     * @see org.argouml.cognitive.critics.Critic#toDoItem(java.lang.Object, 
     * org.argouml.cognitive.Designer)
     */
    public ToDoItem toDoItem(Object dm, Designer dsgr) {
	Object cls = /*(MClassifier)*/ dm;
	VectorSet offs = computeOffenders(cls);
	return new UMLToDoItem(this, offs, dsgr);
    }

    /**
     * @see org.argouml.cognitive.Poster#stillValid(
     * org.argouml.cognitive.ToDoItem, org.argouml.cognitive.Designer)
     */
    public boolean stillValid(ToDoItem i, Designer dsgr) {
	if (!isActive()) return false;
	VectorSet offs = i.getOffenders();
	Object dm = /*(MClassifier)*/ offs.firstElement();
	//if (!predicate(dm, dsgr)) return false;
	VectorSet newOffs = computeOffenders(dm);
	boolean res = offs.equals(newOffs);
	return res;
    }

    /**
     * @param cls is the UML entity that is being checked.
     * @return the list of offenders
     */
    public VectorSet computeOffenders(Object/*MClassifier*/ cls) {
	Collection asc = ModelFacade.getAssociationEnds(cls);
	if (asc == null || asc.size() == 0) return null;

	Enumeration descendEnum =
	    GenDescendantClasses.getSINGLETON().gen(cls);
	if (!descendEnum.hasMoreElements()) return null;
	VectorSet descendants = new VectorSet();
	while (descendEnum.hasMoreElements())
	    descendants.addElement(descendEnum.nextElement());

	//TODO: GenNavigableClasses?
	int nAsc = asc.size();
	VectorSet offs = null;
	for (Iterator iter = asc.iterator(); iter.hasNext();) {
	    Object ae = /*(MAssociationEnd)*/ iter.next();
	    Object a = ModelFacade.getAssociation(ae);
	    List conn = new ArrayList(ModelFacade.getConnections(a));
	    if (conn.size() != 2) continue;
	    Object otherEnd = /*(MAssociationEnd)*/ conn.get(0);
	    if (ae == conn.get(0))
		otherEnd = /*(MAssociationEnd)*/ conn.get(1);
	    if (!ModelFacade.isNavigable(otherEnd)) continue;
	    Object otherCls = ModelFacade.getType(otherEnd);
	    if (descendants.contains(otherCls)) {
		if (offs == null) {
		    offs = new VectorSet();
		    offs.addElement(cls);
		}
		offs.addElement(a);
		offs.addElement(otherCls);
	    }
	}
	return offs;
    }

} /* end class CrSubclassReference */