// $Id: CrUselessAbstract.java,v 1.13 2004/09/21 19:03:26 mvw Exp $
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// File: CrUselessAbstract.java
// Classes: CrUselessAbstract
// Original Author: jrobbins@ics.uci.edu
// $Id: CrUselessAbstract.java,v 1.13 2004/09/21 19:03:26 mvw Exp $

package org.argouml.uml.cognitive.critics;

import java.util.Enumeration;
import java.util.Vector;

import org.argouml.cognitive.Designer;
import org.argouml.cognitive.Goal;
import org.argouml.model.ModelFacade;

import org.tigris.gef.util.ChildGenerator;
import org.tigris.gef.util.EnumerationEmpty;
import org.tigris.gef.util.VectorSet;

/** A critic to detect when a class can never have instances (of
 *  itself of any subclasses). */
public class CrUselessAbstract extends CrUML {

    /**
     * The constructor.
     * 
     */
    public CrUselessAbstract() {
	setHeadline("Define Concrete (Sub)Class");
	addSupportedDecision(CrUML.DEC_INHERITANCE);
	addSupportedGoal(Goal.getUnspecifiedGoal());
	addTrigger("specialization");
	addTrigger("isAbstract");
    }

    /**
     * @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 false;
	Object cls = /*(MClass)*/ dm;
	if (!ModelFacade.isAbstract(cls))
	    return false;  // original class was not abstract
	VectorSet derived =
	    (new VectorSet(cls)).reachable(new ChildGenDerivedClasses());
	Enumeration subclasses = derived.elements();
	while (subclasses.hasMoreElements()) {
	    Object c = /*(MClass)*/ subclasses.nextElement();
	    if (!ModelFacade.isAbstract(c))
		return false;  // found a concrete subclass
	}
	return true; // no concrete subclasses defined, this class is "useless"
    }

} /* end class CrUselessAbstract */



class ChildGenDerivedClasses implements ChildGenerator {
    public Enumeration gen(Object o) {
	Object c = /*(MClass)*/ o;
	Vector specs = new Vector(ModelFacade.getSpecializations(c));
	if (specs == null) {
	    return EnumerationEmpty.theInstance();
	}
	// TODO: it would be nice to have a EnumerationXform
	// and a Functor object in uci.util
	Vector specClasses = new Vector(specs.size());
	Enumeration elems = specs.elements();
	while (elems.hasMoreElements()) {
	    Object g = /*(MGeneralization)*/ elems.nextElement();
	    Object ge = ModelFacade.getChild(g);
	    if (ge != null) {
		specClasses.addElement(ge);
	    }
	}
	return specClasses.elements();
    }
} /* end class derivedClasses */