Add Graph#getEdges to allow for multi edges

src/de/tudarmstadt/maki/simonstrator/api/common/graph/BasicGraph.java

@@ -22,6 +22,7 @@ package de.tudarmstadt.maki.simonstrator.api.common.graph;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -327,6 +328,17 @@ public class BasicGraph implements Graph {
 		return null;
 	}
 
+	@Override
+	public Collection<IEdge> getEdges(INodeID from, INodeID to) {
+		final List<IEdge> resultSet = new ArrayList<>();
+		for (IEdge edge : edges) {
+			if (edge.toId().equals(to) && edge.fromId().equals(from)) {
+				resultSet.add(edge);
+			}
+		}
+		return resultSet;
+	}
+
 	@Override
 	public IEdge getEdge(EdgeID edgeID) {
 		return this.edgesById.get(edgeID);

src/de/tudarmstadt/maki/simonstrator/api/common/graph/Graph.java

@@ -231,7 +231,7 @@ public interface Graph extends Cloneable {
 	public INode getNode(INodeID nodeId);
 
 	/**
-	 * Returns the edge (if present) between from and to, null otherwise
+	 * Returns some edge (if present) between from and to, null otherwise
 	 * 
 	 * @param from
 	 * @param to
@@ -239,6 +239,15 @@ public interface Graph extends Cloneable {
 	 */
 	public IEdge getEdge(INodeID from, INodeID to);
 
+	/**
+	 * Returns all edges (if present) between from and to, null otherwise
+	 * 
+	 * @param from
+	 * @param to
+	 * @return edge or null
+	 */
+	Collection<IEdge> getEdges(INodeID from, INodeID to);
+
 	/**
 	 * Returns the edge with the given ID.
 	 *