Initial sketch of the virtual network constructs.

Change-Id: Ibcdafb9e56edb29fb37b80d7b0da321ad989c564
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
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+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
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+/*
+ * Copyright 2015 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;
+
+import com.google.common.annotations.Beta;
+import org.onosproject.net.DeviceId;
+
+import java.util.Set;
+
+/**
+ * Service for querying virtual network inventory.
+ */
+@Beta
+public interface VirtualNetworkService {
+
+    /**
+     * Returns a collection of all virtual networks created on behalf of the
+     * specified tenant.
+     *
+     * @param tenantId tenant identifier
+     * @return collection of networks
+     * @throws org.onlab.util.ItemNotFoundException if no such network found
+     */
+    Set<VirtualNetwork> getVirtualNetworks(TenantId tenantId);
+
+    /**
+     * Returns a collection of all virtual devices in the specified network.
+     *
+     * @param networkId network identifier
+     * @return collection of devices
+     * @throws org.onlab.util.ItemNotFoundException if no such network found
+     */
+    Set<VirtualDevice> getVirtualDevices(NetworkId networkId);
+
+    /**
+     * Returns collection of all virtual links in the specified network.
+     *
+     * @param networkId network identifier
+     * @return collection of links
+     * @throws org.onlab.util.ItemNotFoundException if no such network found
+     */
+    Set<VirtualLink> getVirtualLinks(NetworkId networkId);
+
+    /**
+     * Returns list of all virtual ports of the specified device.
+     *
+     * @param networkId network identifier
+     * @param deviceId  device identifier
+     * @return list of ports
+     * @throws org.onlab.util.ItemNotFoundException if no such network found
+     */
+    Set<VirtualPort> getVirtualPorts(NetworkId networkId, DeviceId deviceId);
+
+    /**
+     * Returns implementation of the specified service class for operating
+     * in the context of the given network.
+     * <p>
+     * The following services will be available:
+     * <ul>
+     * <li>{@link org.onosproject.net.device.DeviceService}</li>
+     * <li>{@link org.onosproject.net.link.LinkService}</li>
+     * <li>{@link org.onosproject.net.host.HostService}</li>
+     * <li>{@link org.onosproject.net.topology.TopologyService}</li>
+     * <li>{@link org.onosproject.net.topology.PathService}</li>
+     * <li>{@link org.onosproject.net.flow.FlowRuleService}</li>
+     * <li>{@link org.onosproject.net.flowobjective.FlowObjectiveService}</li>
+     * <li>{@link org.onosproject.net.intent.IntentService}</li>
+     * </ul>
+     *
+     * @param networkId    network identifier
+     * @param serviceClass service class
+     * @param <T>          type of service
+     * @return implementation class
+     * @throws org.onlab.util.ItemNotFoundException    if no such network found
+     * @throws org.onlab.osgi.ServiceNotFoundException if no implementation found
+     */
+    <T> T get(NetworkId networkId, Class<T> serviceClass);
+
+}