--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/draw2d/graph/PopulateRanks.d	Sun Aug 03 00:52:14 2008 +0200
@@ -0,0 +1,91 @@
+/*******************************************************************************
+ * Copyright (c) 2003, 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
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.draw2d.graph.PopulateRanks;
+
+import dwt.dwthelper.utils;
+import dwtx.dwtxhelper.Collection;
+import dwtx.draw2d.graph.RevertableChange;
+import dwtx.draw2d.graph.GraphVisitor;
+import dwtx.draw2d.graph.DirectedGraph;
+import dwtx.draw2d.graph.RankList;
+import dwtx.draw2d.graph.Rank;
+import dwtx.draw2d.graph.Node;
+import dwtx.draw2d.graph.Edge;
+import dwtx.draw2d.graph.VirtualNodeCreation;
+
+/**
+ * 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.
+ * <P>
+ * 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 : GraphVisitor {
+
+private Stack changes;
+
+public this(){
+    changes = new Stack();
+}
+/**
+ * @see GraphVisitor#visit(DirectedGraph)
+ */
+public void visit(DirectedGraph g) {
+    if (g.forestRoot !is 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 !is null) {
+                prev.right = cur;
+            }
+            prev = cur;
+        }
+    }
+    for (int i = 0; i < changes.size(); i++) {
+        RevertableChange change = cast(RevertableChange)changes.get(i);
+        change.revert();
+    }
+}
+
+}