Initial opendaylight infrastructure commit!!

[controller.git] / third-party / net.sf.jung2 / src / main / java / edu / uci / ics / jung / algorithms / scoring / util / UniformDegreeWeight.java

diff --git a/third-party/net.sf.jung2/src/main/java/edu/uci/ics/jung/algorithms/scoring/util/UniformDegreeWeight.java b/third-party/net.sf.jung2/src/main/java/edu/uci/ics/jung/algorithms/scoring/util/UniformDegreeWeight.java
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+/**
+ * Copyright (c) 2008, the JUNG Project and the Regents of the University 
+ * of California
+ * All rights reserved.
+ *
+ * This software is open-source under the BSD license; see either
+ * "license.txt" or
+ * http://jung.sourceforge.net/license.txt for a description.
+ * Created on Jul 14, 2008
+ * 
+ */
+package edu.uci.ics.jung.algorithms.scoring.util;
+
+import org.apache.commons.collections15.Transformer;
+
+import edu.uci.ics.jung.graph.Hypergraph;
+import edu.uci.ics.jung.graph.util.EdgeType;
+
+/**
+ * An edge weight function that assigns weights as uniform
+ * transition probabilities.
+ * For undirected edges, returns 1/degree(v) (where 'v' is the
+ * vertex in the VEPair.
+ * For directed edges, returns 1/outdegree(source(e)) (where 'e'
+ * is the edge in the VEPair).
+ * Throws an <code>IllegalArgumentException</code> if the input 
+ * edge is neither EdgeType.UNDIRECTED nor EdgeType.DIRECTED.
+ *
+ */
+public class UniformDegreeWeight<V, E> implements
+               Transformer<VEPair<V, E>, Double> 
+{
+    private Hypergraph<V, E> graph;
+    
+    /**
+     * Creates an instance for the specified graph.
+     */
+    public UniformDegreeWeight(Hypergraph<V, E> graph)
+    {
+        this.graph = graph;
+    }
+
+       /**
+        * @see org.apache.commons.collections15.Transformer#transform(java.lang.Object)
+        */
+       public Double transform(VEPair<V, E> ve_pair) 
+       {
+               E e = ve_pair.getE();
+               V v = ve_pair.getV();
+               EdgeType edge_type = graph.getEdgeType(e);
+               if (edge_type == EdgeType.UNDIRECTED)
+                       return 1.0 / graph.degree(v);
+               if (edge_type == EdgeType.DIRECTED)
+                       return 1.0 / graph.outDegree(graph.getSource(e));
+               throw new IllegalArgumentException("can't handle edge type: " + edge_type);
+       }
+
+}