org.eclipse.gmf.runtime.draw2d.ui/src/org/eclipse/gmf/runtime/draw2d/ui/graph/JointIncomingEdges.java

/******************************************************************************
 * Copyright (c) 2008 IBM Corporation and others.
 * 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:
 *    IBM Corporation - initial API and implementation 
 ****************************************************************************/
package org.eclipse.gmf.runtime.draw2d.ui.graph;

import org.eclipse.draw2d.graph.Edge;
import org.eclipse.draw2d.graph.EdgeList;
import org.eclipse.draw2d.graph.Node;

/**
 * A set of incoming edges that acts like one edge.
 * Used internally for laying out connected border nodes.
 * 
 * @author aboyko
 * @since 2.1
 */
class JointIncomingEdges extends Edge implements JointEdges {
	
	private BorderNode joint;
	
	EdgeList edges = new EdgeList();
	
	private Edge leadingEdge = null;
	private int leadingCost = Integer.MAX_VALUE;
	
	public JointIncomingEdges(BorderNode joint) {
		super(new Node(), new Node());
		this.joint = joint;
		source = target = joint.borderNodeParent;
	}
	
	public Edge getLeadingEdge() {
		if (leadingEdge == null) {
			for (int i = 0; i < edges.size(); i++) {
				Edge e = edges.getEdge(i);
				int cost = getBendpointX(e) - e.target.x - e.target.getOffsetIncoming(); 
				if (Math.abs(cost) < leadingCost) {
					leadingCost = Math.abs(cost);
					leadingEdge = e;
				}
			}
		}
		return leadingEdge;
	}
		
	public BorderNode getJoint() {
		return joint;
	}
	
	private int getBendpointX(Edge e) {
		Node node = e.vNodes == null ? e.source : e.vNodes.getNode(e.vNodes.size() - 1);
		return node.x + node.getOffsetOutgoing();
	}
	
}