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/*******************************************************************************
* 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;
import java.util.Stack;
/**
* This class takes a DirectedGraph with an optimal rank assignment and a
* spanning tree, and populates the ranks of the DirectedGraph. Virtual nodes
* are inserted for edges that span 1 or more ranks.
*
* Ranks are populated using a pre-order depth-first traversal of the spanning
* tree. For each node, all edges requiring virtual nodes are added to the
* ranks.
*
* @author Randy Hudson
* @since 2.1.2
*/
class PopulateRanks extends GraphVisitor {
private Stack changes = new Stack();
/**
* @see GraphVisitor#visit(DirectedGraph)
*/
public void visit(DirectedGraph g) {
if (g.forestRoot != null) {
for (int i = g.forestRoot.outgoing.size() - 1; i >= 0; i--)
g.removeEdge(g.forestRoot.outgoing.getEdge(i));
g.removeNode(g.forestRoot);
}
g.ranks = new RankList();
for (int i = 0; i < g.nodes.size(); i++) {
Node node = g.nodes.getNode(i);
g.ranks.getRank(node.rank).add(node);
}
for (int i = 0; i < g.nodes.size(); i++) {
Node node = g.nodes.getNode(i);
for (int j = 0; j < node.outgoing.size();) {
Edge e = node.outgoing.getEdge(j);
if (e.getLength() > 1)
changes.push(new VirtualNodeCreation(e, g));
else
j++;
}
}
}
/**
* @see GraphVisitor#revisit(DirectedGraph)
*/
public void revisit(DirectedGraph g) {
for (int r = 0; r < g.ranks.size(); r++) {
Rank rank = g.ranks.getRank(r);
Node prev = null, cur;
for (int n = 0; n < rank.size(); n++) {
cur = rank.getNode(n);
cur.left = prev;
if (prev != null) {
prev.right = cur;
}
prev = cur;
}
}
for (int i = 0; i < changes.size(); i++) {
RevertableChange change = (RevertableChange) changes.get(i);
change.revert();
}
}
}