/* $Id: ActivityDiagramLayouter.java 17852 2010-01-12 19:53:56Z 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:

  *    mvw

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

  *

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

  */

 // Copyright (c) 2005-2006 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.diagram.activity.layout;

 import java.awt.Dimension;

 import java.awt.Point;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 import org.argouml.model.Model;

 import org.argouml.uml.diagram.ArgoDiagram;

 import org.argouml.uml.diagram.layout.LayoutedObject;

 import org.argouml.uml.diagram.layout.Layouter;

 import org.tigris.gef.presentation.Fig;

 /**

  * A simple layout class for Activity Diagrams. It lays out the states in a

  * single column, densely packed on the assumption that they'll be split into

  * one or more swim lanes by the user. The graph is traversed starting at the

  * initial state and states are placed in the position where they are first

  * encountered. Nothing sophisticated is done for cycles or nodes with multiple

  * incoming or outgoing edges.

  * 

  * @author Tom Morris

  * 

  */

 public class ActivityDiagramLayouter implements Layouter {

     /*

      * The diagram to be laid out.

      */

     private ArgoDiagram diagram;

     /*

      * List of objects.

      * 

      * NOTE: This methods which read/write this don't appear to be used.

      */

     private List objects = new ArrayList();

     /*

      * Point at which to start layout (initial state goes here). The X

      * coordinate must be greater than half the width of the widest figure to

      * be placed (because figures are centered on this location).

      */

     private static final Point STARTING_POINT = new Point(100, 10);

     /*

      * Amount to increment Y position by for each node placed. We pack them

      * densely on the assumption that the user is going to split them into at

      * least two swimlanes.

      */

     private static final int OFFSET_Y = 25;

     /*

      * FinalState element for ActivityDiagram

      */

     private Object finalState = null;

     /**

      * Construct a new layout engine for an ActivityDiagram.

      * @param d the ActivityDiagram to be laid out.

      */

     public ActivityDiagramLayouter(ArgoDiagram d)  {

         this.diagram = d;

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#add(org.argouml.uml.diagram.layout.LayoutedObject)

      */

     public void add(LayoutedObject object) {

         objects.add(object);

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#remove(org.argouml.uml.diagram.layout.LayoutedObject)

      */

     public void remove(LayoutedObject object) {

         objects.remove(object);

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#getObjects()

      */

     public LayoutedObject[] getObjects() {

         return (LayoutedObject[]) objects.toArray();

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#getObject(int)

      */

     public LayoutedObject getObject(int index) {

         return (LayoutedObject) objects.get(index);

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#layout()

      */

     public void layout() {

         Object first = null;

         // Find our Initial State

         for (Iterator it = diagram.getNodes().iterator(); it.hasNext();) {

             Object node = it.next();

             if (Model.getFacade().isAPseudostate(node) 

                     && Model.getDataTypesHelper().equalsINITIALKind(

                             Model.getFacade().getKind(node))) {

                 first = node;

                 break;

             } 

         }

         assert first != null;

         assert Model.getFacade().getIncomings(first).isEmpty();

         // Place all the nodes

         int lastIndex = placeNodes(new ArrayList(), first, 0);

         // Place the final state last with a little separation

         Point location = new Point(STARTING_POINT);

         location.y += OFFSET_Y * (lastIndex + 2);

         diagram.getContainingFig(finalState).setLocation(location);

     }

     /*

      * Recursively place all nodes pointed to by outgoing transitions.

      * 

      * Because of the recursive algorithm multiple outgoing transitions

      * will end up very lopsided because one entire subgraph will be done

      * before dealing with the other transition(s).

      * 

      * @param seen set of nodes seen so far

      * @param node the node to collect neighbors for

      */

     private int placeNodes(List seen, Object node, int index) {

         if (!seen.contains(node)) {

             seen.add(node);

             if (Model.getFacade().isAFinalState(node)) {

                 finalState = node;

             }

             Fig fig = diagram.getContainingFig(node);

             Point location = new Point(STARTING_POINT.x - fig.getWidth() / 2,

                     STARTING_POINT.y + OFFSET_Y * index++);

             //System.out.println("Setting location to " + location);

             fig.setLocation(location);

             for (Iterator it = Model.getFacade().getOutgoings(node).iterator(); 

                     it.hasNext();) {

                 index = placeNodes(seen, Model.getFacade().getTarget(it.next()),

                                   index);

             }

         }

         return index;

     }

     /*

      * @see org.argouml.uml.diagram.layout.Layouter#getMinimumDiagramSize()

      */

     public Dimension getMinimumDiagramSize() {

         return new Dimension(

                 STARTING_POINT.x + 300,

                 STARTING_POINT.y + OFFSET_Y * objects.size()

         );

     }

 }