// $Id: CrMergeClasses.java,v 1.14 2004/09/21 19:03:27 mvw Exp $
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package org.argouml.uml.cognitive.critics;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.argouml.cognitive.Designer;
import org.argouml.cognitive.ToDoItem;
import org.argouml.model.ModelFacade;

/** A critic to check whether to classes sharing a 1..1 association can or
 *  should be combined.
 */
public class CrMergeClasses extends CrUML {

    /**
     * The constructor.
     * 
     */
    public CrMergeClasses() {
	setHeadline("Consider Combining Classes");
	setPriority(ToDoItem.LOW_PRIORITY);
	addSupportedDecision(CrUML.DEC_CLASS_SELECTION); 
	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;
	Collection ends = ModelFacade.getAssociationEnds(cls);
	if (ends == null || ends.size() != 1) return NO_PROBLEM;
	Object myEnd = /*(MAssociationEnd)*/ ends.iterator().next();
	Object asc = ModelFacade.getAssociation(myEnd);
	List conns = new ArrayList(ModelFacade.getConnections(asc));
	Object ae0 = /*(MAssociationEnd)*/ conns.get(0);
	Object ae1 = /*(MAssociationEnd)*/ conns.get(1);
	// both ends must be classes, otherwise there is nothing to merge
	if (!(ModelFacade.isAClass(ModelFacade.getType(ae0)) 
            && ModelFacade.isAClass(ModelFacade.getType(ae1)))) 
	    return NO_PROBLEM;
	// both ends must be navigable, otherwise there is nothing to merge
	if (!(ModelFacade.isNavigable(ae0) 
            && ModelFacade.isNavigable(ae1)))
	    return NO_PROBLEM;
	if (ModelFacade.getMultiplicity(ae0)
            .equals(ModelFacade.M1_1_MULTIPLICITY) 
                && ModelFacade.getMultiplicity(ae1)
                    .equals(ModelFacade.M1_1_MULTIPLICITY))
	    return PROBLEM_FOUND;
	return NO_PROBLEM;
    }

} /* end class CrMergeClasses */