/* $Id: CrOperNameConflict.java 17849 2010-01-12 19:50:34Z 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:

  *    maurelio1234

  *****************************************************************************

  *

  * Some portions of this file was previously release using the BSD License:

  */

 // Copyright (c) 1996-2007 The Regents of the University of California. All

 // Rights Reserved. Permission to use, copy, modify, and distribute this

 // software and its documentation without fee, and without a written

 // agreement is hereby granted, provided that the above copyright notice

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 package org.argouml.uml.cognitive.critics;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.Set;

 import javax.swing.Icon;

 import org.argouml.cognitive.Critic;

 import org.argouml.cognitive.Designer;

 import org.argouml.model.Model;

 import org.argouml.uml.cognitive.UMLDecision;

 /**

  * A critic to detect when a class has operations with two matching

  * signatures.<p>

  *

  * Takes each operation in turn and compares its signature with all

  * earlier operations. This version corrects and earlier bug, which

  * checked for matching names as well as types in the parameter

  * list.<p>

  *

  * <em>Warning</em>. The algorithm in is quadratic in the number of

  * operations. It could be computationally demanding on a design where

  * classes have a lot of operations. See the {@link #predicate2}

  * method for possible solutions.<p>

  *

  * See the ArgoUML User Manual: Change Names or Signatures in <artifact>

  *

  * @author jrobbins@ics.uci.edu

  */

 public class CrOperNameConflict extends CrUML {

     /**

      * Constructor for the critic.<p>

      *

      * Sets up the resource name, which will allow headline and

      * description to found for the current locale. Provides design

      * issue categories (METHODS, NAMING), sets a knowledge type

      * (SYNTAX) and adds triggers for metaclasses "behaviouralFeature"

      * and feature_name".<p>

      */

     public CrOperNameConflict() {

         setupHeadAndDesc();

         addSupportedDecision(UMLDecision.METHODS);

         addSupportedDecision(UMLDecision.NAMING);

         setKnowledgeTypes(Critic.KT_SYNTAX);

         // These may not actually make any difference at present (the code

         // behind addTrigger needs more work).

         addTrigger("behavioralFeature");

         addTrigger("feature_name");

     }

     /**

      * The trigger for the critic.<p>

      *

      * Finds all the operations for the given classifier. Takes each

      * operation in turn and compares its signature with all earlier

      * operations. This version corrects an earlier bug, which checked

      * for matching names as well as types in the parameter list.<p>

      *

      * <em>Note</em>. The signature ignores any return parameters in

      * looking for a match. This is in line with Java/C++.<p>

      *

      * We do not need to worry about signature clashes that are

      * inherited (overloading). This is something encouraged in many

      * OO environments to facilitate polymorphism.<p>

      *

      * This algorithm is quadratic in the number of operations. If

      * this became a problem, we would have to consider sorting the

      * operations list and comparing only adjacent pairs

      * (potentially O(n log n) performance).<p>

      *

      * @param  dm    the {@link Object} to be checked against the critic.

      *

      * @param  dsgr  the {@link 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}.

      */

     @Override

     public boolean predicate2(Object dm, Designer dsgr) {

         // Only do this for classifiers

         if (!(Model.getFacade().isAClassifier(dm))) {

             return NO_PROBLEM;

         }

         // Get all the features (giving up if there are none). Then loop

         // through finding all operations. Each time we find one, we compare

         // its signature with all previous (held in collection operSeen), and then

         // if it doesn't match add it to the collection.

         Collection operSeen = new ArrayList();

         for (Object op : Model.getFacade().getOperations(dm)) {

             // Compare against all earlier operations. If there's a match we've

             // found the problem

             for (Object o : operSeen) {

                 if (signaturesMatch(op, o)) {

                     return PROBLEM_FOUND;

                 }

             }

             // Add to the collection and round to look at the next one

             operSeen.add(op);

         }

         // If we drop out here, there was no match and we have no problem

         return NO_PROBLEM;

     }

     /**

      * Return the icon to be used for the clarifier for this critic.<p>

      *

      * A clarifier is the graphical highlight used to show the

      * presence of a critique. For example wavy colored underlines

      * beneath operations.<p>

      *

      * In this case it will be a wavy line under the second of the

      * clashing operations.<p>

      *

      * @return       The {@link javax.swing.Icon Icon} to use.

      */

     @Override

     public Icon getClarifier() {

         return ClOperationCompartment.getTheInstance();

     }

     /**

      * Sees if the signatures of two Operations are the same.<p>

      *

      * Checks for matching operation name, and list of parameter

      * types. The order of the parameters is significant.

      *

      * This version also checks for the parameter kind, since

      * otherwise, "op(int a)" and "op():int" appear to have the same

      * signature. Purists would probably suggest that the kind should

      * match exactly. However we only differentiate the return

      * parameter(s). It is unlikely that any practical OO language

      * would be able to distinguish instantiation of in from out from

      * inout parameters.<p>

      *

      * We ignore return parameters completely. This is in line with

      * Java/C++ which regard <code>int x(int, int)</code> and

      * <code>double x(int, int)</code> as having the same

      * signature.<p>

      *

      * If you need to modify this method, take care, since there are

      * numerous "telegraph pole" problems involved in working through

      * pairs of mixed lists.<p>

      *

      * @param op1 the first operation whose signature is being compared.

      * @param op2 the second operation whose signature is being compared.

      *

      * @return    <code>true</code> if the signatures match, <code>false</code>

      *            otherwise.

      */

     private boolean signaturesMatch(Object op1, Object op2) {

         // Check that the names match.

         String name1 = Model.getFacade().getName(op1);

         if (name1 == null) {

             return false;

         }

         String name2 = Model.getFacade().getName(op2);

         if (name2 == null) {

             return false;

         }

         if (!name1.equals(name2)) {

             return false;

         }

         // Check that the parameter lists match.

         Iterator params1 = Model.getFacade().getParameters(op1).iterator();

         Iterator params2 = Model.getFacade().getParameters(op2).iterator();

         while (params1.hasNext()

                && params2.hasNext()) {

             // Get the next non-return parameter. Null if non left.

             Object p1 = null;

             while (p1 == null && params1.hasNext()) {

                 p1 = params1.next();

                 if (Model.getFacade().isReturn(p1))

                     p1 = null;

             }

             Object p2 = null;

             while (p2 == null && params1.hasNext()) {

                 p2 = params1.next();

                 if (Model.getFacade().isReturn(p2))

                     p2 = null;

             }

             if (p1 == null && p2 == null)

                 return true;        // Both lists have the same length

             // Different lengths:

             if (p1 == null || p2 == null) {

                 return false;

             }

             // Compare the type of the parameters. If any of the types is

             // null, then we have a match.

             Object p1type = Model.getFacade().getType(p1);

             if (p1type == null) {

                 continue;

             }

             Object p2type = Model.getFacade().getType(p2);

             if (p2type == null) {

                 continue;

             }

             if (!p1type.equals(p2type)) {

                 return false;

             }

             // This pair of params where the same. Lets check the next pair.

         }

         if (!params1.hasNext() && !params2.hasNext()) {

             // Both lists have the same length.

             return true;

         }

         return false;

     }

     /*

      * @see org.argouml.uml.cognitive.critics.CrUML#getCriticizedDesignMaterials()

      */

     public Set<Object> getCriticizedDesignMaterials() {

         Set<Object> ret = new HashSet<Object>();

         ret.add(Model.getMetaTypes().getClassifier());

         return ret;

     }

 }