SimpleGraph.java

/*******************************************************************************
 * Copyright 2005, CHISEL Group, University of Victoria, Victoria, BC, Canada.
 * 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:
 *     The Chisel Group, University of Victoria
 *******************************************************************************/
package org.eclipse.zest.layouts.exampleStructures;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.eclipse.zest.layouts.LayoutEntity;
import org.eclipse.zest.layouts.LayoutGraph;
import org.eclipse.zest.layouts.LayoutRelationship;


/**
 * Create a very simple graph that can be used in the layout algorithms
 * 
 * @author Casey Best
 * @author Chris Callendar
 */
public class SimpleGraph implements LayoutGraph {
	
	Map objectsToNodes;
	List relationships;
	
	public SimpleGraph() {
		objectsToNodes = new HashMap();
		relationships = new ArrayList();
	}
	
	/**
	 * Adds the node.
	 * @param node	The node to add.
	 */
	public void addEntity(LayoutEntity node) {
		if (node instanceof SimpleNode) {
			objectsToNodes.put(((SimpleNode)node).getRealObject(), node);
		}
	}
	
	/**
	 * Creates a LayoutEntity containing an object.
	 */
	public LayoutEntity addObjectNode(Object object) {
	    SimpleNode simpleNode = (SimpleNode) objectsToNodes.get (object);
		if (simpleNode == null) {
			simpleNode = new SimpleNode(object);
			objectsToNodes.put (object, simpleNode);
		}
		return simpleNode;
		
	}
	
	/**
	 * Add a relationship between two objects.  Layout algorithms need to know
	 * whether a relationship is one way or bi-directional.  This method assumes that 
	 * all relationships are bi-direcional and have the same weight. 
	 */
	public void addObjectRelationship (Object sourceNode, Object destinationNode) {
		addObjectRelationship(sourceNode, destinationNode, true, 1);
	}
	
	/**
	 * Add a relationship between two objects.  Layout algorithms need to know
	 * whether a relationship is one way or bi-directional.  
	 */
	public void addObjectRelationship (Object sourceObject, Object destinationObject, boolean bidirectional, int weight) {
		addObjectNode(sourceObject);
		addObjectNode(destinationObject);
		SimpleNode sourceNode = (SimpleNode) objectsToNodes.get(sourceObject);
		SimpleNode destinationNode = (SimpleNode) objectsToNodes.get(destinationObject);
		SimpleRelationship simpleRelationship = new SimpleRelationship(sourceNode, destinationNode, bidirectional, weight);
		relationships.add(simpleRelationship);
	}

	/* (non-Javadoc)
	 * @see ca.uvic.cs.chisel.layouts.LayoutGraph#addRelationship(ca.uvic.cs.chisel.layouts.LayoutEntity, ca.uvic.cs.chisel.layouts.LayoutEntity)
	 */
	public void addRelationship(LayoutEntity srcNode, LayoutEntity destNode) {
		addRelationship(srcNode, destNode, true, 1);
	}
	
	/* (non-Javadoc)
	 * @see ca.uvic.cs.chisel.layouts.LayoutGraph#addRelationship(ca.uvic.cs.chisel.layouts.LayoutEntity, ca.uvic.cs.chisel.layouts.LayoutEntity, boolean, int)
	 */
	public void addRelationship(LayoutEntity srcNode, LayoutEntity destNode, boolean bidirectional, int weight) {
		addEntity(srcNode);
		addEntity(destNode);
		SimpleRelationship rel = new SimpleRelationship(srcNode, destNode, bidirectional, weight);
		relationships.add(rel);
	}
	
	/* (non-Javadoc)
	 * @see ca.uvic.cs.chisel.layouts.LayoutGraph#addRelationship(ca.uvic.cs.chisel.layouts.LayoutRelationship)
	 */
	public void addRelationship(LayoutRelationship relationship) {
		relationships.add(relationship);
	}

	/**
	 * Returns a list of SimpleNodes that represent the objects added to this graph using addNode.  Note that
	 * any manipulation to this graph was done on the SimpleNodes, not the real objects.  You
	 * must still manipulate them yourself.
	 */
	public List getEntities() {
		return new ArrayList (objectsToNodes.values());
	}

	/**
	 * Returns a list of SimpleRelationships that represent the objects added to this graph using addRelationship.
	 */
	public List getRelationships() {
		return relationships;
	}
	
	/**
	 * Checks the relationships to see if they are all bidirectional. 
	 * @return boolean if all edges are bidirectional.
	 */
	public boolean isBidirectional() {
		boolean isBidirectional = true;
		for (Iterator iter = relationships.iterator(); iter.hasNext(); ) {
			SimpleRelationship rel = (SimpleRelationship) iter.next();
			if (!rel.isBidirectionalInLayout()) {
				isBidirectional = false;
				break;
			}
		}
		return isBidirectional;
	}
}