Add K-shortest path API to PathService.
Change-Id: I96732666f31a7a2b2df9a16f63e77bc0a367da83
diff --git a/core/api/src/main/java/org/onosproject/net/topology/HopCountLinkWeigher.java b/core/api/src/main/java/org/onosproject/net/topology/HopCountLinkWeigher.java
new file mode 100644
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+++ b/core/api/src/main/java/org/onosproject/net/topology/HopCountLinkWeigher.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2017-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.net.topology;
+
+import static org.onosproject.net.Link.State.ACTIVE;
+import static org.onosproject.net.Link.Type.INDIRECT;
+
+import org.onlab.graph.ScalarWeight;
+import org.onlab.graph.Weight;
+
+/**
+ * Link weight for measuring link cost as hop count with indirect links
+ * being as expensive as traversing the entire graph to assume the worst.
+ */
+public class HopCountLinkWeigher implements LinkWeigher {
+
+ public static final LinkWeigher DEFAULT_HOP_COUNT_WEIGHER = new HopCountLinkWeigher();
+
+ private static final ScalarWeight ZERO = new ScalarWeight(0.0);
+ private static final ScalarWeight ONE = new ScalarWeight(1.0);
+ private static final ScalarWeight DEFAULT_INDIRECT = new ScalarWeight(Short.MAX_VALUE);
+
+ private final ScalarWeight indirectLinkCost;
+
+ /**
+ * Creates a new hop-count weight.
+ */
+ public HopCountLinkWeigher() {
+ this.indirectLinkCost = DEFAULT_INDIRECT;
+ }
+
+ /**
+ * Creates a new hop-count weight with the specified cost of indirect links.
+ *
+ * @param indirectLinkCost indirect link cost
+ */
+ public HopCountLinkWeigher(double indirectLinkCost) {
+ this.indirectLinkCost = new ScalarWeight(indirectLinkCost);
+ }
+
+ @Override
+ public Weight weight(TopologyEdge edge) {
+ if (edge.link().state() == ACTIVE) {
+ return edge.link().type() == INDIRECT ? indirectLinkCost : ONE;
+ } else {
+ return getNonViableWeight();
+ }
+ }
+
+ @Override
+ public Weight getInitialWeight() {
+ return ZERO;
+ }
+
+ @Override
+ public Weight getNonViableWeight() {
+ return ScalarWeight.NON_VIABLE_WEIGHT;
+ }
+
+}