// $Id: CrNavFromInterface.java,v 1.12 2004/09/21 19:03:26 mvw Exp $
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// File: CrNavFromInterface.java
// Classes: CrNavFromInterface.java

package org.argouml.uml.cognitive.critics;

import java.util.Iterator;
import org.argouml.cognitive.Designer;
import org.argouml.cognitive.critics.Critic;
import org.argouml.model.ModelFacade;


// Use Model through ModelFacade

/**
 * A critic to detect navigation from an Interface to a Class in an
 * Association.  This is not permitted in UML, since it would require
 * the Interface to hold state to represent the association
 * reference.

 *
 * The critic will trigger whenever an association between an
 * interface and a class is navigable from the interface.

 *
 * @see 
 * ArgoUML User Manual: N
 * @author jrobbins@ics.uci.edu
 */
public class CrNavFromInterface extends CrUML {

    /**
     * Constructor for the critic.

     *
     * Sets up the resource name, which will allow headline and description
     * to found for the current locale (replaces deprecated setHeadline and sd
     * methods). Provides a design issue category (RELATIONSHIPS) and knowledge
     * type (SYNTAX). Adds trigger "end_navigable".

     */
    public CrNavFromInterface() {

        // Set the resource label, which will get the headline and description
        // appropriate for the locale

        setResource("CrNavFromInterface");

        // Specify design issue category and knowledge type

        addSupportedDecision(CrUML.DEC_RELATIONSHIPS);
        setKnowledgeTypes(Critic.KT_SYNTAX);

        // This may not actually make any difference at present (the code
        // behind addTrigger needs more work).

        addTrigger("end_navigable");
    }

    /**
     * The trigger for the critic.

     *
     * Applies to Associations only, not AssociationRoles. The reason is
     * that an AssociationRole cannot have greater navigability than the
     * Association it specializes, so if the critic has addressed the
     * Association, the AssociationRole will effectively be addressed. There
     * may of course be a need for a critic to check that Association Roles do
     * match their parents in this respect!

     *
     * As a consequence, we also don't need to check for associations with
     * ClassifierRoles.

     * 
     * Iterate over all the AssociationEnds. We only have a problem if:

     * 

     *   
There is an end connected to an Interface; and
     *   
An end other than that end is navigable.
     * 
     *
     * @param  dm    the object to be checked against the critic
     * @param  dsgr  the designer creating the model. Not used, this is for
     *               future development of ArgoUML
     * @return       {@link #PROBLEM_FOUND PROBLEM_FOUND} if the critic is
     *               triggered, otherwise {@link #NO_PROBLEM NO_PROBLEM}.  */
    
    public boolean predicate2(Object dm, Designer dsgr) {

        // Only look at Associations

        if (!(ModelFacade.isAAssociation(dm))) {
            return NO_PROBLEM;
        }

        if (ModelFacade.isAAssociationRole(dm)) {
            return NO_PROBLEM;
        }

        // Iterate over all the AssociationEnds. We only have a problem if 1)
        // there is an end connected to an Interface and 2) an end other than
        // that end is navigable. 

        Iterator assocEnds = ModelFacade.getConnections(dm).iterator();

        boolean haveInterfaceEnd  = false;  // End at an Interface?
        boolean otherEndNavigable = false;  // Navigable other end?

        while (assocEnds.hasNext()) {

            // The next AssociationEnd

            Object ae = assocEnds.next();

            // If its an interface we have an interface end, otherwise its
            // something else and we should see if it is navigable. We don't
            // check that the end is a Classifier, rather than its child
            // ClassifierRole, since we have effectively eliminated that
            // possiblity in rejecting AssociationRoles above.

	    Object type = ModelFacade.getType(ae);

            if (ModelFacade.isAInterface(type)) {
                haveInterfaceEnd = true;
            }
	    else if (ModelFacade.isNavigable(ae)) {
                otherEndNavigable = true;
            }

            // We can give up looking if we've hit both criteria

            if (haveInterfaceEnd && otherEndNavigable) {
                return PROBLEM_FOUND;
            }
        }

        // If we drop out we didn't meet both criteria, and all is well.

        return NO_PROBLEM;
    }

} /* end class CrNavFromInterface */