ONOS-2184 - initial impl. of  virtual network path service; move path related methods from PathManager to AbstractPathService (since they are reused for VirtualNetworkPathService).

Change-Id: Ib4211d69a15c23a50de420b771877bb659539c22
diff --git a/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java b/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java
new file mode 100644
index 0000000..0292f70
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/topology/AbstractPathService.java
@@ -0,0 +1,255 @@
+/*
+ *
+ *  * Copyright 2016-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 com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultDisjointPath;
+import org.onosproject.net.DefaultEdgeLink;
+import org.onosproject.net.DefaultPath;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.DisjointPath;
+import org.onosproject.net.EdgeLink;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.Host;
+import org.onosproject.net.HostId;
+import org.onosproject.net.HostLocation;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.host.HostService;
+import org.onosproject.net.provider.ProviderId;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Helper class for path service.
+ */
+public abstract class AbstractPathService {
+
+    private static final String ELEMENT_ID_NULL = "Element ID cannot be null";
+    private static final EdgeLink NOT_HOST = new NotHost();
+
+    private static final ProviderId PID = new ProviderId("core", "org.onosproject.core");
+    private static final PortNumber P0 = PortNumber.portNumber(0);
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected TopologyService topologyService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected HostService hostService;
+
+    public Set<Path> getPaths(ElementId src, ElementId dst, LinkWeight weight) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePaths(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<Path> paths = weight == null ?
+                topologyService.getPaths(topology, srcDevice, dstDevice) :
+                topologyService.getPaths(topology, srcDevice, dstDevice, weight);
+
+        return edgeToEdgePaths(srcEdge, dstEdge, paths);
+    }
+
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<DisjointPath> paths = weight == null ?
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice) :
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight);
+
+        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+    }
+
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight,
+                                              Map<Link, Object> riskProfile) {
+        checkNotNull(src, ELEMENT_ID_NULL);
+        checkNotNull(dst, ELEMENT_ID_NULL);
+
+        // Get the source and destination edge locations
+        EdgeLink srcEdge = getEdgeLink(src, true);
+        EdgeLink dstEdge = getEdgeLink(dst, false);
+
+        // If either edge is null, bail with no paths.
+        if (srcEdge == null || dstEdge == null) {
+            return ImmutableSet.of();
+        }
+
+        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
+        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
+
+        // If the source and destination are on the same edge device, there
+        // is just one path, so build it and return it.
+        if (srcDevice.equals(dstDevice)) {
+            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
+        }
+
+        // Otherwise get all paths between the source and destination edge
+        // devices.
+        Topology topology = topologyService.currentTopology();
+        Set<DisjointPath> paths = weight == null ?
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, riskProfile) :
+                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight, riskProfile);
+
+        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+    }
+
+    // Finds the host edge link if the element ID is a host id of an existing
+    // host. Otherwise, if the host does not exist, it returns null and if
+    // the element ID is not a host ID, returns NOT_HOST edge link.
+    private EdgeLink getEdgeLink(ElementId elementId, boolean isIngress) {
+        if (elementId instanceof HostId) {
+            // Resolve the host, return null.
+            Host host = hostService.getHost((HostId) elementId);
+            if (host == null) {
+                return null;
+            }
+            return new DefaultEdgeLink(PID, new ConnectPoint(elementId, P0),
+                                       host.location(), isIngress);
+        }
+        return NOT_HOST;
+    }
+
+    // Produces a set of edge-to-edge paths using the set of infrastructure
+    // paths and the given edge links.
+    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink) {
+        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
+        endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, null));
+        return endToEndPaths;
+    }
+
+    // Produces a set of edge-to-edge paths using the set of infrastructure
+    // paths and the given edge links.
+    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink, Set<Path> paths) {
+        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
+        for (Path path : paths) {
+            endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, path));
+        }
+        return endToEndPaths;
+    }
+
+    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink) {
+        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
+        endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, null));
+        return endToEndPaths;
+    }
+
+    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink,
+                                                             Set<DisjointPath> paths) {
+        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
+        for (DisjointPath path : paths) {
+            endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, path));
+        }
+        return endToEndPaths;
+    }
+
+    // Produces a direct edge-to-edge path.
+    private Path edgeToEdgePath(EdgeLink srcLink, EdgeLink dstLink, Path path) {
+        List<Link> links = Lists.newArrayListWithCapacity(2);
+        double cost = 0;
+
+        // Add source and destination edge links only if they are real and
+        // add the infrastructure path only if it is not null.
+        if (srcLink != NOT_HOST) {
+            links.add(srcLink);
+            cost++;
+        }
+        if (path != null) {
+            links.addAll(path.links());
+            cost += path.cost();
+        }
+        if (dstLink != NOT_HOST) {
+            links.add(dstLink);
+            cost++;
+        }
+        return new DefaultPath(PID, links, cost);
+    }
+
+    // Produces a direct edge-to-edge path.
+    private DisjointPath edgeToEdgePathD(EdgeLink srcLink, EdgeLink dstLink, DisjointPath path) {
+        Path primary = null;
+        Path backup = null;
+        if (path != null) {
+            primary = path.primary();
+            backup = path.backup();
+        }
+        return new DefaultDisjointPath(PID, (DefaultPath) edgeToEdgePath(srcLink, dstLink, primary),
+                                       (DefaultPath) edgeToEdgePath(srcLink, dstLink, backup));
+    }
+
+
+    // Special value for edge link to represent that this is really not an
+    // edge link since the src or dst are really an infrastructure device.
+    private static class NotHost extends DefaultEdgeLink implements EdgeLink {
+        NotHost() {
+            super(PID, new ConnectPoint(HostId.NONE, P0),
+                  new HostLocation(DeviceId.NONE, P0, 0L), false);
+        }
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/topology/impl/PathManager.java b/core/net/src/main/java/org/onosproject/net/topology/impl/PathManager.java
index e6f6387..9a04fff 100644
--- a/core/net/src/main/java/org/onosproject/net/topology/impl/PathManager.java
+++ b/core/net/src/main/java/org/onosproject/net/topology/impl/PathManager.java
@@ -15,43 +15,23 @@
  */
 package org.onosproject.net.topology.impl;
 
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Sets;
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
-import org.apache.felix.scr.annotations.Reference;
-import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
-import org.onosproject.net.ConnectPoint;
-import org.onosproject.net.DefaultEdgeLink;
-import org.onosproject.net.DefaultPath;
 import org.onosproject.net.DisjointPath;
-import org.onosproject.net.DefaultDisjointPath;
-import org.onosproject.net.DeviceId;
-import org.onosproject.net.EdgeLink;
 import org.onosproject.net.ElementId;
-import org.onosproject.net.Host;
-import org.onosproject.net.HostId;
-import org.onosproject.net.HostLocation;
 import org.onosproject.net.Link;
 import org.onosproject.net.Path;
-import org.onosproject.net.PortNumber;
-import org.onosproject.net.host.HostService;
-import org.onosproject.net.provider.ProviderId;
 import org.onosproject.net.topology.LinkWeight;
 import org.onosproject.net.topology.PathService;
-import org.onosproject.net.topology.Topology;
-import org.onosproject.net.topology.TopologyService;
+import org.onosproject.net.topology.AbstractPathService;
 import org.slf4j.Logger;
 
-import java.util.List;
 import java.util.Set;
 import java.util.Map;
 
 
-import static com.google.common.base.Preconditions.checkNotNull;
 import static org.slf4j.LoggerFactory.getLogger;
 import static org.onosproject.security.AppGuard.checkPermission;
 import static org.onosproject.security.AppPermission.Type.*;
@@ -63,23 +43,11 @@
  */
 @Component(immediate = true)
 @Service
-public class PathManager implements PathService {
+public class PathManager extends AbstractPathService implements PathService {
 
-    private static final String ELEMENT_ID_NULL = "Element ID cannot be null";
-
-    private static final ProviderId PID = new ProviderId("core", "org.onosproject.core");
-    private static final PortNumber P0 = PortNumber.portNumber(0);
-
-    private static final EdgeLink NOT_HOST = new NotHost();
 
     private final Logger log = getLogger(getClass());
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected TopologyService topologyService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected HostService hostService;
-
     @Activate
     public void activate() {
         log.info("Started");
@@ -100,38 +68,10 @@
     @Override
     public Set<Path> getPaths(ElementId src, ElementId dst, LinkWeight weight) {
         checkPermission(TOPOLOGY_READ);
-
-        checkNotNull(src, ELEMENT_ID_NULL);
-        checkNotNull(dst, ELEMENT_ID_NULL);
-
-        // Get the source and destination edge locations
-        EdgeLink srcEdge = getEdgeLink(src, true);
-        EdgeLink dstEdge = getEdgeLink(dst, false);
-
-        // If either edge is null, bail with no paths.
-        if (srcEdge == null || dstEdge == null) {
-            return ImmutableSet.of();
-        }
-
-        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
-        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
-
-        // If the source and destination are on the same edge device, there
-        // is just one path, so build it and return it.
-        if (srcDevice.equals(dstDevice)) {
-            return edgeToEdgePaths(srcEdge, dstEdge);
-        }
-
-        // Otherwise get all paths between the source and destination edge
-        // devices.
-        Topology topology = topologyService.currentTopology();
-        Set<Path> paths = weight == null ?
-                topologyService.getPaths(topology, srcDevice, dstDevice) :
-                topologyService.getPaths(topology, srcDevice, dstDevice, weight);
-
-        return edgeToEdgePaths(srcEdge, dstEdge, paths);
+        return super.getPaths(src, dst, weight);
     }
 
+
     @Override
     public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst) {
         checkPermission(TOPOLOGY_READ);
@@ -141,35 +81,7 @@
     @Override
     public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight) {
         checkPermission(TOPOLOGY_READ);
-        checkNotNull(src, ELEMENT_ID_NULL);
-        checkNotNull(dst, ELEMENT_ID_NULL);
-
-        // Get the source and destination edge locations
-        EdgeLink srcEdge = getEdgeLink(src, true);
-        EdgeLink dstEdge = getEdgeLink(dst, false);
-
-        // If either edge is null, bail with no paths.
-        if (srcEdge == null || dstEdge == null) {
-            return ImmutableSet.of();
-        }
-
-        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
-        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
-
-        // If the source and destination are on the same edge device, there
-        // is just one path, so build it and return it.
-        if (srcDevice.equals(dstDevice)) {
-            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
-        }
-
-        // Otherwise get all paths between the source and destination edge
-        // devices.
-        Topology topology = topologyService.currentTopology();
-        Set<DisjointPath> paths = weight == null ?
-                topologyService.getDisjointPaths(topology, srcDevice, dstDevice) :
-                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight);
-
-        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+        return super.getDisjointPaths(src, dst, weight);
     }
 
     @Override
@@ -183,126 +95,7 @@
     public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, LinkWeight weight,
                                               Map<Link, Object> riskProfile) {
         checkPermission(TOPOLOGY_READ);
-        checkNotNull(src, ELEMENT_ID_NULL);
-        checkNotNull(dst, ELEMENT_ID_NULL);
-
-        // Get the source and destination edge locations
-        EdgeLink srcEdge = getEdgeLink(src, true);
-        EdgeLink dstEdge = getEdgeLink(dst, false);
-
-        // If either edge is null, bail with no paths.
-        if (srcEdge == null || dstEdge == null) {
-            return ImmutableSet.of();
-        }
-
-        DeviceId srcDevice = srcEdge != NOT_HOST ? srcEdge.dst().deviceId() : (DeviceId) src;
-        DeviceId dstDevice = dstEdge != NOT_HOST ? dstEdge.src().deviceId() : (DeviceId) dst;
-
-        // If the source and destination are on the same edge device, there
-        // is just one path, so build it and return it.
-        if (srcDevice.equals(dstDevice)) {
-            return edgeToEdgePathsDisjoint(srcEdge, dstEdge);
-        }
-
-        // Otherwise get all paths between the source and destination edge
-        // devices.
-        Topology topology = topologyService.currentTopology();
-        Set<DisjointPath> paths = weight == null ?
-                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, riskProfile) :
-                topologyService.getDisjointPaths(topology, srcDevice, dstDevice, weight, riskProfile);
-
-        return edgeToEdgePathsDisjoint(srcEdge, dstEdge, paths);
+        return super.getDisjointPaths(src, dst, weight, riskProfile);
     }
 
-    // Finds the host edge link if the element ID is a host id of an existing
-    // host. Otherwise, if the host does not exist, it returns null and if
-    // the element ID is not a host ID, returns NOT_HOST edge link.
-    private EdgeLink getEdgeLink(ElementId elementId, boolean isIngress) {
-        if (elementId instanceof HostId) {
-            // Resolve the host, return null.
-            Host host = hostService.getHost((HostId) elementId);
-            if (host == null) {
-                return null;
-            }
-            return new DefaultEdgeLink(PID, new ConnectPoint(elementId, P0),
-                                       host.location(), isIngress);
-        }
-        return NOT_HOST;
-    }
-
-    // Produces a set of edge-to-edge paths using the set of infrastructure
-    // paths and the given edge links.
-    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink) {
-        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
-        endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, null));
-        return endToEndPaths;
-    }
-
-    // Produces a set of edge-to-edge paths using the set of infrastructure
-    // paths and the given edge links.
-    private Set<Path> edgeToEdgePaths(EdgeLink srcLink, EdgeLink dstLink, Set<Path> paths) {
-        Set<Path> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
-        for (Path path : paths) {
-            endToEndPaths.add(edgeToEdgePath(srcLink, dstLink, path));
-        }
-        return endToEndPaths;
-    }
-
-    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink) {
-        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(1);
-        endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, null));
-        return endToEndPaths;
-    }
-
-    private Set<DisjointPath> edgeToEdgePathsDisjoint(EdgeLink srcLink, EdgeLink dstLink, Set<DisjointPath> paths) {
-        Set<DisjointPath> endToEndPaths = Sets.newHashSetWithExpectedSize(paths.size());
-        for (DisjointPath path : paths) {
-            endToEndPaths.add(edgeToEdgePathD(srcLink, dstLink, path));
-        }
-        return endToEndPaths;
-    }
-
-    // Produces a direct edge-to-edge path.
-    private Path edgeToEdgePath(EdgeLink srcLink, EdgeLink dstLink, Path path) {
-        List<Link> links = Lists.newArrayListWithCapacity(2);
-        double cost = 0;
-
-        // Add source and destination edge links only if they are real and
-        // add the infrastructure path only if it is not null.
-        if (srcLink != NOT_HOST) {
-            links.add(srcLink);
-            cost++;
-        }
-        if (path != null) {
-            links.addAll(path.links());
-            cost += path.cost();
-        }
-        if (dstLink != NOT_HOST) {
-            links.add(dstLink);
-            cost++;
-        }
-        return new DefaultPath(PID, links, cost);
-    }
-
-    // Produces a direct edge-to-edge path.
-    private DisjointPath edgeToEdgePathD(EdgeLink srcLink, EdgeLink dstLink, DisjointPath path) {
-        Path primary = null;
-        Path backup = null;
-        if (path != null) {
-            primary = path.primary();
-            backup = path.backup();
-        }
-        return new DefaultDisjointPath(PID, (DefaultPath) edgeToEdgePath(srcLink, dstLink, primary),
-                                       (DefaultPath) edgeToEdgePath(srcLink, dstLink, backup));
-    }
-
-
-    // Special value for edge link to represent that this is really not an
-    // edge link since the src or dst are really an infrastructure device.
-    private static class NotHost extends DefaultEdgeLink implements EdgeLink {
-        NotHost() {
-            super(PID, new ConnectPoint(HostId.NONE, P0),
-                  new HostLocation(DeviceId.NONE, P0, 0L), false);
-        }
-    }
 }
diff --git a/core/net/src/test/java/org/onosproject/net/topology/impl/PathManagerTest.java b/core/net/src/test/java/org/onosproject/net/topology/impl/PathManagerTest.java
index c1a4715..18e6402 100644
--- a/core/net/src/test/java/org/onosproject/net/topology/impl/PathManagerTest.java
+++ b/core/net/src/test/java/org/onosproject/net/topology/impl/PathManagerTest.java
@@ -18,6 +18,7 @@
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.onlab.junit.TestUtils;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.ElementId;
 import org.onosproject.net.Host;
@@ -53,11 +54,11 @@
     private FakeHostMgr fakeHostMgr = new FakeHostMgr();
 
     @Before
-    public void setUp() {
+    public void setUp() throws Exception {
         mgr = new PathManager();
         service = mgr;
-        mgr.topologyService = fakeTopoMgr;
-        mgr.hostService = fakeHostMgr;
+        TestUtils.setField(mgr, "topologyService", fakeTopoMgr);
+        TestUtils.setField(mgr, "hostService", fakeHostMgr);
         mgr.activate();
     }
 
diff --git a/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkManager.java b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkManager.java
index 5330833..56c4fd5 100644
--- a/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkManager.java
+++ b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkManager.java
@@ -61,6 +61,7 @@
 import org.onosproject.net.link.LinkService;
 import org.onosproject.net.provider.AbstractListenerProviderRegistry;
 import org.onosproject.net.provider.AbstractProviderService;
+import org.onosproject.net.topology.PathService;
 import org.onosproject.net.topology.TopologyService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -371,6 +372,8 @@
             service = new VirtualNetworkIntentService(this, network, new DefaultServiceDirectory());
         } else if (serviceKey.serviceClass.equals(HostService.class)) {
             service = new VirtualNetworkHostService(this, network);
+        } else if (serviceKey.serviceClass.equals(PathService.class)) {
+            service = new VirtualNetworkPathService(this, network);
         } else {
             return null;
         }
diff --git a/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathService.java b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathService.java
new file mode 100644
index 0000000..5dfc62b
--- /dev/null
+++ b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathService.java
@@ -0,0 +1,81 @@
+/*
+ *
+ *  * Copyright 2016-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.incubator.net.virtual.impl;
+
+import org.onosproject.incubator.net.virtual.VirtualNetwork;
+import org.onosproject.incubator.net.virtual.VirtualNetworkService;
+import org.onosproject.net.DisjointPath;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.Link;
+import org.onosproject.net.Path;
+import org.onosproject.net.host.HostService;
+import org.onosproject.net.topology.LinkWeight;
+import org.onosproject.net.topology.PathService;
+import org.onosproject.net.topology.AbstractPathService;
+import org.onosproject.net.topology.TopologyService;
+
+import java.util.Map;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Path service implementation built on the virtual network service.
+ */
+public class VirtualNetworkPathService extends AbstractPathService
+        implements PathService, VnetService {
+
+    private static final String NETWORK_NULL = "Network ID cannot be null";
+
+    private final VirtualNetwork network;
+
+    /**
+     * Creates a new virtual network path service object.
+     *
+     * @param virtualNetworkManager virtual network manager service
+     * @param network               virtual network
+     */
+
+    public VirtualNetworkPathService(VirtualNetworkService virtualNetworkManager, VirtualNetwork network) {
+        checkNotNull(network, NETWORK_NULL);
+        this.network = network;
+        topologyService = virtualNetworkManager.get(network.id(), TopologyService.class);
+        hostService = virtualNetworkManager.get(network.id(), HostService.class);
+    }
+
+    @Override
+    public Set<Path> getPaths(ElementId src, ElementId dst) {
+        return getPaths(src, dst, null);
+    }
+
+    @Override
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst) {
+        return getDisjointPaths(src, dst, (LinkWeight) null);
+    }
+
+    @Override
+    public Set<DisjointPath> getDisjointPaths(ElementId src, ElementId dst, Map<Link, Object> riskProfile) {
+        return getDisjointPaths(src, dst, null, riskProfile);
+    }
+
+    @Override
+    public VirtualNetwork network() {
+        return network;
+    }
+}
diff --git a/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathServiceTest.java b/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathServiceTest.java
new file mode 100644
index 0000000..6e5f4e8
--- /dev/null
+++ b/incubator/net/src/test/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkPathServiceTest.java
@@ -0,0 +1,235 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.impl;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.junit.TestUtils;
+import org.onosproject.common.event.impl.TestEventDispatcher;
+import org.onosproject.core.CoreService;
+import org.onosproject.incubator.net.virtual.TenantId;
+import org.onosproject.incubator.net.virtual.VirtualDevice;
+import org.onosproject.incubator.net.virtual.VirtualLink;
+import org.onosproject.incubator.net.virtual.VirtualNetwork;
+import org.onosproject.incubator.store.virtual.impl.DistributedVirtualNetworkStore;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultPort;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.DisjointPath;
+import org.onosproject.net.ElementId;
+import org.onosproject.net.Link;
+import org.onosproject.net.NetTestTools;
+import org.onosproject.net.Path;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.TestDeviceParams;
+import org.onosproject.net.intent.FakeIntentManager;
+import org.onosproject.net.intent.TestableIntentService;
+import org.onosproject.net.topology.LinkWeight;
+import org.onosproject.net.topology.PathService;
+import org.onosproject.store.service.TestStorageService;
+
+import java.util.Set;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Junit tests for VirtualNetworkPathService.
+ */
+public class VirtualNetworkPathServiceTest extends TestDeviceParams {
+    private final String tenantIdValue1 = "TENANT_ID1";
+
+    private VirtualNetworkManager manager;
+    private DistributedVirtualNetworkStore virtualNetworkManagerStore;
+    private final TestableIntentService intentService = new FakeIntentManager();
+
+    @Before
+    public void setUp() throws Exception {
+        virtualNetworkManagerStore = new DistributedVirtualNetworkStore();
+
+        CoreService coreService = new TestCoreService();
+        virtualNetworkManagerStore.setCoreService(coreService);
+        TestUtils.setField(virtualNetworkManagerStore, "storageService", new TestStorageService());
+        virtualNetworkManagerStore.activate();
+
+        manager = new VirtualNetworkManager();
+        manager.store = virtualNetworkManagerStore;
+        manager.intentService = intentService;
+        NetTestTools.injectEventDispatcher(manager, new TestEventDispatcher());
+        manager.activate();
+    }
+
+    @After
+    public void tearDown() {
+        virtualNetworkManagerStore.deactivate();
+        manager.deactivate();
+        NetTestTools.injectEventDispatcher(manager, null);
+    }
+
+    /**
+     * Sets up an empty virtual network (no devices, links).
+     *
+     * @return virtual network
+     */
+    private VirtualNetwork setupEmptyVnet() {
+        manager.registerTenantId(TenantId.tenantId(tenantIdValue1));
+        return manager.createVirtualNetwork(TenantId.tenantId(tenantIdValue1));
+    }
+
+    /**
+     * Creates a virtual network for further testing.
+     *
+     * @return virtual network
+     */
+    private VirtualNetwork setupVnet() {
+        manager.registerTenantId(TenantId.tenantId(tenantIdValue1));
+        VirtualNetwork virtualNetwork = manager.createVirtualNetwork(TenantId.tenantId(tenantIdValue1));
+        VirtualDevice virtualDevice1 =
+                manager.createVirtualDevice(virtualNetwork.id(), DID1);
+        VirtualDevice virtualDevice2 =
+                manager.createVirtualDevice(virtualNetwork.id(), DID2);
+        VirtualDevice virtualDevice3 =
+                manager.createVirtualDevice(virtualNetwork.id(), DID3);
+        VirtualDevice virtualDevice4 =
+                manager.createVirtualDevice(virtualNetwork.id(), DID4);
+
+        ConnectPoint cp11 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice1, 1);
+        ConnectPoint cp12 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice1, 2);
+        ConnectPoint cp23 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice2, 3);
+        ConnectPoint cp24 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice2, 4);
+        ConnectPoint cp35 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice3, 5);
+        ConnectPoint cp36 = createConnectPointAndVirtualPort(virtualNetwork, virtualDevice3, 6);
+        VirtualLink link1 = manager.createVirtualLink(virtualNetwork.id(), cp11, cp23);
+        virtualNetworkManagerStore.updateLink(link1, link1.tunnelId(), Link.State.ACTIVE);
+        VirtualLink link2 = manager.createVirtualLink(virtualNetwork.id(), cp23, cp11);
+        virtualNetworkManagerStore.updateLink(link2, link2.tunnelId(), Link.State.ACTIVE);
+        VirtualLink link3 = manager.createVirtualLink(virtualNetwork.id(), cp24, cp35);
+        virtualNetworkManagerStore.updateLink(link3, link3.tunnelId(), Link.State.ACTIVE);
+        VirtualLink link4 = manager.createVirtualLink(virtualNetwork.id(), cp35, cp24);
+        virtualNetworkManagerStore.updateLink(link4, link4.tunnelId(), Link.State.ACTIVE);
+        VirtualLink link5 = manager.createVirtualLink(virtualNetwork.id(), cp12, cp36);
+        virtualNetworkManagerStore.updateLink(link5, link5.tunnelId(), Link.State.ACTIVE);
+        VirtualLink link6 = manager.createVirtualLink(virtualNetwork.id(), cp36, cp12);
+        virtualNetworkManagerStore.updateLink(link6, link6.tunnelId(), Link.State.ACTIVE);
+
+        return virtualNetwork;
+    }
+
+    /**
+     * Creates a connect point and related virtual port.
+     *
+     * @param vnet virtual network
+     * @param vDev virtual device
+     * @param portNumber port number
+     * @return connect point
+     */
+    private ConnectPoint createConnectPointAndVirtualPort(
+            VirtualNetwork vnet, VirtualDevice vDev, long portNumber) {
+        ConnectPoint cp = new ConnectPoint(vDev.id(), PortNumber.portNumber(portNumber));
+        manager.createVirtualPort(vnet.id(), cp.deviceId(), cp.port(),
+                                  new DefaultPort(vDev, cp.port(), true));
+        return cp;
+    }
+
+    /**
+     * Tests getPaths(), getDisjointPaths()
+     * on a non-empty virtual network.
+     */
+    @Test
+    public void testGetPathsOnNonEmptyVnet() {
+        VirtualNetwork vnet = setupVnet();
+        PathService pathService = manager.get(vnet.id(), PathService.class);
+
+        // src and dest are in vnet and are connected by a virtual link
+        Set<Path> paths = pathService.getPaths(DID1, DID3);
+        validatePaths(paths, 1, 1, DID1, DID3, 1.0);
+
+        LinkWeight linkWeight = edge -> 2.0;
+        paths = pathService.getPaths(DID1, DID3, linkWeight);
+        validatePaths(paths, 1, 1, DID1, DID3, 2.0);
+
+        Set<DisjointPath> disjointPaths = pathService.getDisjointPaths(DID1, DID3);
+        validatePaths(disjointPaths, 1, 1, DID1, DID3, 1.0);
+
+        disjointPaths = pathService.getDisjointPaths(DID1, DID3, linkWeight);
+        validatePaths(disjointPaths, 1, 1, DID1, DID3, 2.0);
+
+        // src and dest are in vnet but are not connected
+        paths = pathService.getPaths(DID4, DID3);
+        assertEquals("incorrect path count", 0, paths.size());
+
+        disjointPaths = pathService.getDisjointPaths(DID4, DID3);
+        assertEquals("incorrect path count", 0, disjointPaths.size());
+
+        // src is in vnet, but dest is not in vnet.
+        DeviceId nonExistentDeviceId = DeviceId.deviceId("nonExistentDevice");
+        paths = pathService.getPaths(DID2, nonExistentDeviceId);
+        assertEquals("incorrect path count", 0, paths.size());
+
+        disjointPaths = pathService.getDisjointPaths(DID2, nonExistentDeviceId);
+        assertEquals("incorrect path count", 0, disjointPaths.size());
+    }
+
+    /**
+     * Tests getPaths(), getDisjointPaths()
+     * on an empty virtual network.
+     */
+    @Test
+    public void testGetPathsOnEmptyVnet() {
+        VirtualNetwork vnet = setupEmptyVnet();
+        PathService pathService = manager.get(vnet.id(), PathService.class);
+
+        Set<Path> paths = pathService.getPaths(DID1, DID3);
+        assertEquals("incorrect path count", 0, paths.size());
+
+        Set<DisjointPath> disjointPaths = pathService.getDisjointPaths(DID1, DID3);
+        assertEquals("incorrect path count", 0, disjointPaths.size());
+    }
+
+    /**
+     * Tests getPaths() using a null source device on an empty virtual network.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testGetPathsWithNullSrc() {
+        VirtualNetwork vnet = setupEmptyVnet();
+        PathService pathService = manager.get(vnet.id(), PathService.class);
+        pathService.getPaths(null, DID3);
+    }
+
+    /**
+     * Tests getPaths() using a null destination device on a non-empty virtual network.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testGetPathsWithNullDest() {
+        VirtualNetwork vnet = setupVnet();
+        PathService pathService = manager.get(vnet.id(), PathService.class);
+        pathService.getPaths(DID1, null);
+    }
+
+
+    // Makes sure the set of paths meets basic expectations.
+    private void validatePaths(Set<? extends Path> paths, int count, int length,
+                               ElementId src, ElementId dst, double cost) {
+        assertEquals("incorrect path count", count, paths.size());
+        for (Path path : paths) {
+            assertEquals("incorrect length", length, path.links().size());
+            assertEquals("incorrect source", src, path.src().elementId());
+            assertEquals("incorrect destination", dst, path.dst().elementId());
+            assertEquals("incorrect cost", cost, path.cost(), 0);
+        }
+    }
+}