Introducing concept of a physical or logical region to facilitate
support of geographically distributed cluster and to lay ground
for multiple/filtered topology layouts.

Added implementation of manager and store; unit-tests included.

Change-Id: Ia01673a0b711b8785c0ea68768552c2f61d7ea6d
diff --git a/core/api/src/main/java/org/onosproject/net/region/RegionStore.java b/core/api/src/main/java/org/onosproject/net/region/RegionStore.java
new file mode 100644
index 0000000..6ba1354
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/region/RegionStore.java
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2016 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.region;
+
+import org.onosproject.cluster.NodeId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.store.Store;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Manages inventory of regions of devices; not intended for direct use.
+ */
+public interface RegionStore extends Store<RegionEvent, RegionStoreDelegate> {
+
+    /**
+     * Returns set of all regions.
+     *
+     * @return set of regions
+     */
+    Set<Region> getRegions();
+
+    /**
+     * Returns the region with the specified identifier.
+     *
+     * @param regionId region identifier
+     * @return region
+     * @throws org.onlab.util.ItemNotFoundException if region with given
+     *                                              id does not exist
+     */
+    Region getRegion(RegionId regionId);
+
+    /**
+     * Returns the region to which the specified device belongs.
+     *
+     * @param deviceId device identifier
+     * @return region or null if device does not belong to any region
+     */
+    Region getRegionForDevice(DeviceId deviceId);
+
+    /**
+     * Returns the set of devices that belong to the specified region.
+     *
+     * @param regionId region identifier
+     * @return set of identifiers for devices in the given region
+     */
+    Set<DeviceId> getRegionDevices(RegionId regionId);
+
+    /**
+     * Creates a new region using the supplied data.
+     *
+     * @param regionId      region identifier
+     * @param name          friendly name
+     * @param type          region type
+     * @param masterNodeIds list of master nodes; null implies empty list
+     * @return new region descriptor
+     * @throws IllegalArgumentException if item already exists
+     */
+    Region createRegion(RegionId regionId, String name, Region.Type type,
+                        List<Set<NodeId>> masterNodeIds);
+
+    /**
+     * Updates the specified new region using the supplied data.
+     *
+     * @param regionId      region identifier
+     * @param name          friendly name
+     * @param type          region type
+     * @param masterNodeIds list of master nodes; null implies empty list
+     * @return new region descriptor
+     * @throws IllegalArgumentException if item already exists
+     */
+    Region updateRegion(RegionId regionId, String name, Region.Type type,
+                        List<Set<NodeId>> masterNodeIds);
+
+    /**
+     * Removes the specified region using the new set of data.
+     *
+     * @param regionId region identifier
+     */
+    void removeRegion(RegionId regionId);
+
+    /**
+     * Adds the specified collection of devices to the region.
+     *
+     * @param regionId  region identifier
+     * @param deviceIds list of device identifiers
+     */
+    void addDevices(RegionId regionId, Collection<DeviceId> deviceIds);
+
+    /**
+     * Removes the specified collection of devices from the region.
+     *
+     * @param regionId  region identifier
+     * @param deviceIds list of device identifiers
+     */
+    void removeDevices(RegionId regionId, Collection<DeviceId> deviceIds);
+
+}