/* $Id: CrSingletonViolatedOnlyPrivateConstructors.java 17831 2010-01-12 18:56:55Z linus $
 *****************************************************************************
 * Copyright (c) 2009 Contributors - see below
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    tfmorris
 *****************************************************************************
 *
 * Some portions of this file was previously release using the BSD License:
 */

// Copyright (c) 1996-2007 The Regents of the University of California. All
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package org.argouml.pattern.cognitive.critics;

import java.util.Iterator;

import org.argouml.cognitive.Designer;
import org.argouml.cognitive.ToDoItem;
import org.argouml.model.Model;
import org.argouml.uml.cognitive.UMLDecision;
import org.argouml.uml.cognitive.critics.CrUML;

/**
 * A critic to detect whether a class violates the conditions required for
 * using a Singleton Stereotype.<p>
 *
 * This stereotype is used to indicate a class which only ever has a single
 * instance. The critic will trigger whenever a class has stereotype
 * «Singleton» (or «singleton»), but does not
 * meet the requirements of a Singleton class. These are:
 *
 * <ol>
 *   <li>An static variable to hold the sole instance of the class;
 *   <li>only private constructors to create the sole instance;
 *       (This critic) and
 *   <li>At least one constructor to override the default constructor.
 * </ol>
 *
 * This version includes an implementation for the second tests above!
 * <p>
 * *see ArgoUML User Manual: Singleton Violated
 *
 * @author jrobbins
 */
public class CrSingletonViolatedOnlyPrivateConstructors extends CrUML {

    /**
     * Constructor for the critic.
     *
     * Sets up the resource name, which will allow headline and description
     * to be found for the current locale. Provides a design issue category
     * (PATTERNS), sets a priority for any to-do items (LOW) and adds
     * triggers for metaclasses "stereotype", "structuralFeature" and
     * "associationEnd".
     */

    public CrSingletonViolatedOnlyPrivateConstructors() {
        setupHeadAndDesc();
        addSupportedDecision(UMLDecision.PATTERNS);
        setPriority(ToDoItem.MED_PRIORITY);

        // These may not actually make any difference at present (the code
        // behind addTrigger needs more work).
        addTrigger("stereotype");
        addTrigger("structuralFeature");
        addTrigger("associationEnd");
    }


    /**
     * The trigger for the critic.<p>
     *
     * First check we are actually stereotyped "Singleton" (or we will
     * accept "singleton").<p>
     *
     * Then check for a static attribute with the same type as the Singleton
     * class that will hold the instance of the Singleton class when its
     * created.<p>
     *
     * @param  dm    the {@link java.lang.Object Object} to be checked
     *               against the critic.
     *
     * @param  dsgr  the {@link org.argouml.cognitive.Designer 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 classes
        if (!(Model.getFacade().isAClass(dm))) {
            return NO_PROBLEM;
        }

        // We only look at singletons
        if (!(Model.getFacade().isSingleton(dm))) {
            return NO_PROBLEM;
        }

	Iterator operations = Model.getFacade().getOperations(dm).iterator();

	while (operations.hasNext()) {
	    Object o = operations.next();

	    if (!(Model.getFacade().isConstructor(o))) {
	        continue;
	    }

	    if (!(Model.getFacade().isPrivate(o))) {
	        return PROBLEM_FOUND;
	    }
        }

	return NO_PROBLEM;
    }

} /* end class CrSingletonViolatedOnlyPrivateConstructors */