[ONOS-6806] Add getAvailableDeviceCount method to DeviceStore

Change-Id: I3f9e0bbd502e2a592da98436685fa2a192436ef8

core/api/src/main/java/org/onosproject/net/device/DeviceStore.java

@@ -38,6 +38,13 @@ public interface DeviceStore extends Store<DeviceEvent, DeviceStoreDelegate> {
      */
     int getDeviceCount();
 
+    /**
+     * Returns the number of currently available devices known to the system.
+     *
+     * @return number of devices
+     */
+    int getAvailableDeviceCount();
+
     /**
      * Returns an iterable collection of all devices known to the system.
      *

core/api/src/test/java/org/onosproject/net/device/DeviceStoreAdapter.java

@@ -35,6 +35,11 @@ public class DeviceStoreAdapter implements DeviceStore {
         return 0;
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return 0;
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         return null;

core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java

@@ -125,6 +125,11 @@ public class SimpleDeviceStore
         return devices.size();
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         return Collections.unmodifiableCollection(devices.values());

core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java

@@ -155,6 +155,22 @@ public class SimpleDeviceStoreTest {
         assertEquals("expect 2 uniq devices", 2, deviceStore.getDeviceCount());
     }
 
+    @Test
+    public final void testGetAvailableDeviceCount() {
+        assertEquals("initialy empty", 0, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+
+        deviceStore.markOffline(DID1);
+
+        assertEquals("expect 1 available device", 1, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+
+        assertEquals("expect 2 available devices", 2, deviceStore.getAvailableDeviceCount());
+    }
+
     @Test
     public final void testGetDevices() {
         assertEquals("initialy empty", 0, Iterables.size(deviceStore.getDevices()));

core/store/dist/src/main/java/org/onosproject/store/device/impl/ECDeviceStore.java

@@ -246,6 +246,11 @@ public class ECDeviceStore
         return devices.size();
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
     @Override
     public Device getDevice(DeviceId deviceId) {
         return devices.get(deviceId);

core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java

@@ -275,6 +275,11 @@ public class GossipDeviceStore
         return devices.size();
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         return Collections.unmodifiableCollection(devices.values());

core/store/dist/src/test/java/org/onosproject/store/device/impl/GossipDeviceStoreTest.java

@@ -298,6 +298,22 @@ public class GossipDeviceStoreTest {
         assertEquals("expect 2 uniq devices", 2, deviceStore.getDeviceCount());
     }
 
+    @Test
+    public final void testGetAvailableDeviceCount() {
+        assertEquals("initialy empty", 0, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+
+        deviceStore.markOffline(DID1);
+
+        assertEquals("expect 1 available device", 1, deviceStore.getAvailableDeviceCount());
+
+        deviceStore.markOnline(DID1);
+
+        assertEquals("expect 2 available devices", 2, deviceStore.getAvailableDeviceCount());
+    }
+
     @Test
     public final void testGetDevices() {
         assertEquals("initialy empty", 0, Iterables.size(deviceStore.getDevices()));