--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.draw2d/src/org/eclipse/draw2d/graph/InitialRankSolver.d	Sat Mar 14 18:23:29 2009 +0100
@@ -0,0 +1,126 @@
+/*******************************************************************************
+ * Copyright (c) 2003, 2005 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 org.eclipse.draw2d.graph.InitialRankSolver;
+
+import java.lang.all;
+import org.eclipse.draw2d.graph.GraphVisitor;
+import org.eclipse.draw2d.graph.DirectedGraph;
+import org.eclipse.draw2d.graph.NodeList;
+import org.eclipse.draw2d.graph.Node;
+import org.eclipse.draw2d.graph.EdgeList;
+import org.eclipse.draw2d.graph.Edge;
+
+/**
+ * Assigns a valid rank assignment to all nodes based on their edges.  The assignment is
+ * not optimal in that it does not provide the minimum global length of edge lengths.
+ * @author Randy Hudson
+ * @since 2.1.2
+ */
+class InitialRankSolver : GraphVisitor {
+
+protected DirectedGraph graph;
+protected EdgeList candidates;
+protected NodeList members;
+
+public this(){
+    candidates = new EdgeList();
+    members = new NodeList();
+}
+
+public void visit(DirectedGraph graph) {
+    this.graph = graph;
+    graph.edges.resetFlags(false);
+    graph.nodes.resetFlags();
+    solve();
+}
+
+protected void solve() {
+    if (graph.nodes.size() is 0)
+        return;
+    NodeList unranked = new NodeList(graph.nodes);
+    NodeList rankMe = new NodeList();
+    Node node;
+    int i;
+    while (!unranked.isEmpty()) {
+        rankMe.clear();
+        for (i = 0; i < unranked.size();) {
+            node = unranked.getNode(i);
+            if (node.incoming.isCompletelyFlagged()) {
+                rankMe.add(node);
+                unranked.remove(i);
+            } else
+                i++;
+        }
+        if (rankMe.size() is 0)
+            throw new RuntimeException("Cycle detected in graph"); //$NON-NLS-1$
+        for (i = 0; i < rankMe.size(); i++) {
+            node = rankMe.getNode(i);
+            assignMinimumRank(node);
+            node.outgoing.setFlags(true);
+        }
+    }
+
+    connectForest();
+}
+
+private void connectForest() {
+    List forest = new ArrayList();
+    Stack stack = new Stack();
+    NodeList tree;
+    graph.nodes.resetFlags();
+    for (int i = 0; i < graph.nodes.size(); i++) {
+        Node neighbor, n = graph.nodes.getNode(i);
+        if (n.flag)
+            continue;
+        tree = new NodeList();
+        stack.push(n);
+        while (!stack.isEmpty()) {
+            n = cast(Node) stack.pop();
+            n.flag = true;
+            tree.add(n);
+            for (int s = 0; s < n.incoming.size(); s++) {
+                neighbor = n.incoming.getEdge(s).source;
+                if (!neighbor.flag)
+                    stack.push(neighbor);
+            }
+            for (int s = 0; s < n.outgoing.size(); s++) {
+                neighbor = n.outgoing.getEdge(s).target;
+                if (!neighbor.flag)
+                    stack.push(neighbor);
+            }
+        }
+        forest.add(tree);
+    }
+
+    if (forest.size() > 1) {
+        //connect the forest
+        graph.forestRoot = new Node(stringcast("the forest root")); //$NON-NLS-1$
+        graph.nodes.add(graph.forestRoot);
+        for (int i = 0; i < forest.size(); i++) {
+            tree = cast(NodeList) forest.get(i);
+            graph.edges.add(new Edge(graph.forestRoot, tree.getNode(0), 0, 0));
+        }
+    }
+}
+
+private void assignMinimumRank(Node node) {
+    int rank = 0;
+    Edge e;
+    for (int i1 = 0; i1 < node.incoming.size(); i1++) {
+        e = node.incoming.getEdge(i1);
+        rank = Math.max(rank, e.delta + e.source.rank);
+    }
+    node.rank = rank;
+}
+
+}