| /******************************************************************************* |
| * Copyright (c) 2003, 2010 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.draw2d.graph; |
| |
| /** |
| * A base class for visitors which operate on the graphs spanning tree used to |
| * induce rank assignments. |
| * |
| * @author Randy Hudson |
| * @since 2.1.2 |
| */ |
| abstract class SpanningTreeVisitor extends GraphVisitor { |
| |
| Edge getParentEdge(Node node) { |
| return (Edge) node.workingData[1]; |
| } |
| |
| EdgeList getSpanningTreeChildren(Node node) { |
| return (EdgeList) node.workingData[0]; |
| } |
| |
| protected Node getTreeHead(Edge edge) { |
| if (getParentEdge(edge.source) == edge) |
| return edge.target; |
| return edge.source; |
| } |
| |
| Node getTreeParent(Node node) { |
| Edge e = getParentEdge(node); |
| if (e == null) |
| return null; |
| return e.opposite(node); |
| } |
| |
| protected Node getTreeTail(Edge edge) { |
| if (getParentEdge(edge.source) == edge) |
| return edge.source; |
| return edge.target; |
| } |
| |
| void setParentEdge(Node node, Edge edge) { |
| node.workingData[1] = edge; |
| } |
| |
| } |
