From 254ee6f47eebfc00462c10756a92066e82cc1a96 Mon Sep 17 00:00:00 2001
From: Andrew Branson <andrew@andrewbranson.net>
Date: Tue, 21 Jun 2011 15:46:02 +0200
Subject: Initial commit

---
 .../c2kernel/graph/traversal/GraphTraversal.java   | 85 ++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100755 source/com/c2kernel/graph/traversal/GraphTraversal.java

(limited to 'source/com/c2kernel/graph/traversal/GraphTraversal.java')

diff --git a/source/com/c2kernel/graph/traversal/GraphTraversal.java b/source/com/c2kernel/graph/traversal/GraphTraversal.java
new file mode 100755
index 0000000..abf30f7
--- /dev/null
+++ b/source/com/c2kernel/graph/traversal/GraphTraversal.java
@@ -0,0 +1,85 @@
+package com.c2kernel.graph.traversal;
+
+
+import java.util.Vector;
+
+import com.c2kernel.graph.model.GraphModel;
+import com.c2kernel.graph.model.Vertex;
+
+
+public class GraphTraversal
+{
+    public static final int kUp   = 1;
+    public static final int kDown = 2;
+
+
+    private GraphTraversal()
+    {
+    }
+
+
+    public static Vertex[] getTraversal(GraphModel graphModel, Vertex startVertex, int direction, boolean ignoreBackLinks)
+    {
+        Vector path = new Vector(10, 10);
+
+        graphModel.clearTags(startVertex);
+        visitVertex(startVertex, graphModel, path, direction, startVertex, ignoreBackLinks);
+
+        return vectorToVertexArray(path);
+    }
+
+
+    private static void visitVertex(Vertex vertex, GraphModel graphModel, Vector path, int direction, Object tag, boolean ignoreBackLinks)
+    {
+        Vertex[] children = null;
+        int i = 0;
+
+        if(direction == kDown)
+        {
+            children = graphModel.getOutVertices(vertex);
+        }
+        else
+        {
+            children = graphModel.getInVertices(vertex);
+        }
+
+        vertex.setTag(tag);
+        path.add(vertex);
+
+        for(i=0; i<children.length; i++)
+        {
+            if(!(children[i].hasTag(tag)))
+            {
+                boolean skipBackLink = false;
+                if ( ignoreBackLinks &&
+                    ((vertex.isJoin() && direction == kUp) ||
+                    (vertex.isLoop() && direction == kDown))) {
+                    Vertex[] following = getTraversal(graphModel, children[i], direction, false);
+                    for (int j = 0; j < following.length; j++) {
+                        if (following[j] == vertex) {
+                            skipBackLink = true;
+                            break;
+                        }
+                    }
+                }
+                if (!skipBackLink)
+                    visitVertex(children[i], graphModel, path, direction, tag, ignoreBackLinks);
+            }
+        }
+    }
+
+
+    private static Vertex[] vectorToVertexArray(Vector vector)
+    {
+        Vertex[] vertices = new Vertex[vector.size()];
+        int      i        = 0;
+
+
+        for(i=0; i<vertices.length; i++)
+        {
+            vertices[i] = (Vertex)vector.elementAt(i);
+        }
+
+        return vertices;
+    }
+}
-- 
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