/* $Id: UMLExpressionModel2.java 17881 2010-01-12 21:09:28Z 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:

  *    bobtarling

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

  *

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

  */

 // Copyright (c) 1996-2009 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

 // and this paragraph appear in all copies.  This software program and

 // documentation are copyrighted by The Regents of the University of

 // California. The software program and documentation are supplied "AS

 // IS", without any accompanying services from The Regents. The Regents

 // does not warrant that the operation of the program will be

 // uninterrupted or error-free. The end-user understands that the program

 // was developed for research purposes and is advised not to rely

 // exclusively on the program for any reason.  IN NO EVENT SHALL THE

 // UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

 // SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,

 // ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF

 // THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF

 // SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY

 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 // PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF

 // CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,

 // UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 package org.argouml.uml.ui;

 import java.beans.PropertyChangeEvent;

 import java.beans.PropertyChangeListener;

 import javax.swing.SwingUtilities;

 import org.argouml.model.Model;

 import org.argouml.ui.TabTarget;

 import org.argouml.ui.targetmanager.TargetEvent;

 import org.argouml.ui.targetmanager.TargetListener;

 import org.tigris.gef.presentation.Fig;

 /**

  * The model for an expression. 

  * An expression consists of a body and a language.

  * 

  * @author mkl

  */

 public abstract class UMLExpressionModel2  

     implements TargetListener, PropertyChangeListener {

     private UMLUserInterfaceContainer container;

     private String propertyName;

     private Object expression;

     private boolean mustRefresh;

     private static final String EMPTYSTRING = "";

     private Object target = null;

     /**

      * The constructor.

      *

      * @param c the container of UML user interface components

      * @param name the name of the property

      */

     public UMLExpressionModel2(UMLUserInterfaceContainer c, String name) {

         container = c;

         propertyName = name;

         mustRefresh = true;

     }

     /**

      * When the target is changed, we must refresh.

      */

     public void targetChanged() {

         mustRefresh = true;

         expression = null;

     }

     /**

      * @return the expression

      */

     public abstract Object getExpression();

     /**

      * @param expr the expression

      */

     public abstract void setExpression(Object expr);

     /**

      * @return a new expression

      */

     public abstract Object newExpression();

     /**

      * @return the language of the expression

      */

     public String getLanguage() {

         if (mustRefresh) {

             expression = getExpression();

         }

         if (expression == null) {

             return EMPTYSTRING;

         }

         return Model.getDataTypesHelper().getLanguage(expression);

     }

     /**

      * @return The body text of the expression.

      */

     public String getBody() {

         if (mustRefresh) {

             expression = getExpression();

         }

         if (expression == null) {

             return EMPTYSTRING;

         }

         return Model.getDataTypesHelper().getBody(expression);

     }

     /**

      * @param lang the language of the expression

      */

     public void setLanguage(String lang) {

         boolean mustChange = true;

         if (expression != null) {

             String oldValue =

                 Model.getDataTypesHelper().getLanguage(expression);

             if (oldValue != null && oldValue.equals(lang)) {

                 mustChange = false;

             }

         }

         if (mustChange) {

             String body = EMPTYSTRING;

             if (expression != null

                     && Model.getDataTypesHelper().getBody(expression) != null) {

                 body = Model.getDataTypesHelper().getBody(expression);

             }

             setExpression(lang, body);

         }

     }

     /**

      * @param body the body text of the expression

      */

     public void setBody(String body) {

         boolean mustChange = true;

         if (expression != null) {

             Object oldValue = Model.getDataTypesHelper().getBody(expression);

             if (oldValue != null && oldValue.equals(body)) {

                 mustChange = false;

             }

         }

         if (mustChange) {

             String lang = null;

             if (expression != null) {

                 lang = Model.getDataTypesHelper().getLanguage(expression);

             }

             if (lang == null) {

                 lang = EMPTYSTRING;

             }

             setExpression(lang, body);

         }

     }

     /**

      * @param lang the language of the expression

      * @param body the body text of the expression

      */

     private void setExpression(String lang, String body) {

         // Expressions are DataTypes, not independent model elements

         // be careful not to reuse them

         Object oldExpression = null;

         if (mustRefresh || expression == null) {

             oldExpression = expression;

             expression = newExpression();

         }

         expression = Model.getDataTypesHelper().setLanguage(expression, lang);

         expression = Model.getDataTypesHelper().setBody(expression, body);

         setExpression(expression);

         if (oldExpression != null) {

             Model.getUmlFactory().delete(oldExpression);

         }

     }

     /**

      * @return the container

      */

     protected UMLUserInterfaceContainer getContainer() {

         return container;

     }

     /**

      * TODO: The next text was copied - to adapt.

      * 

      * Sets the target. If the old target is an UML Element, it also removes

      * the model from the element listener list of the target. If the new target

      * is an UML Element, the model is added as element listener to the

      * new target. <p>

      *

      * This function is called when the user changes the target. 

      * Hence, this shall not result in any UML model changes.<p>

      * 

      * This function looks a lot like the one in UMLComboBoxModel2.

      * <p>

      * As a possible future extension, we could allow listening to 

      * other model elements.

      * 

      * @param theNewTarget the new target

      */

     public void setTarget(Object theNewTarget) {

         theNewTarget = theNewTarget instanceof Fig

             ? ((Fig) theNewTarget).getOwner() : theNewTarget;

         if (Model.getFacade().isAUMLElement(target)) {

             Model.getPump().removeModelEventListener(this, target,

                     propertyName);

             // Allow listening to other elements:

             //                removeOtherModelEventListeners(listTarget);

         }

         if (Model.getFacade().isAUMLElement(theNewTarget)) {

             target = theNewTarget;

             Model.getPump().addModelEventListener(this, target,

                     propertyName);

             // Allow listening to other elements:

             //                addOtherModelEventListeners(listTarget);

             if (container instanceof TabTarget) {

                 ((TabTarget) container).refresh();

             }

         } else {

             target = null;

         }

     }

     public void propertyChange(PropertyChangeEvent e) {

         if (target != null && target == e.getSource()) {

             mustRefresh = true;

             expression = null;

             /* This works - we do get an event - and now 

              * refresh the UI: */

             if (container instanceof TabTarget) {

                 SwingUtilities.invokeLater(new Runnable() {

                     public void run() {

                         ((TabTarget) container).refresh();

                         /* TODO: The above statement also refreshes when 

                          * we are not shown (to be verified) - hence 

                          * not entirely correct. */

                     }

                 });

             }

         }

     }

     public void targetAdded(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

     public void targetRemoved(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

     public void targetSet(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

 }