[ONOS-6806] Add getAvailableDeviceCount method to DeviceService

Change-Id: Ieda7e66c1a1d25aa92b55542ecfe59652dac3bc5

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

@@ -38,6 +38,15 @@ public interface DeviceService
      */
     int getDeviceCount();
 
+    /**
+     * Returns the number of currently available devices known to the system.
+     *
+     * @return number of available devices
+     */
+    default int getAvailableDeviceCount() {
+        return getDeviceCount();
+    }
+
     /**
      * Returns a collection of the currently known infrastructure
      * devices.

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

@@ -55,6 +55,11 @@ public class DeviceServiceAdapter implements DeviceService {
         return 0;
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return 0;
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         return Collections.emptyList();

core/api/src/main/java/org/onosproject/net/utils/ForwardingDeviceService.java

@@ -62,6 +62,11 @@ public abstract class ForwardingDeviceService implements DeviceService {
         return delegate.getDeviceCount();
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        return delegate.getAvailableDeviceCount();
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         return delegate.getDevices();

core/net/src/main/java/org/onosproject/net/device/impl/DeviceManager.java

@@ -208,6 +208,12 @@ public class DeviceManager
         return store.getDeviceCount();
     }
 
+    @Override
+    public int getAvailableDeviceCount() {
+        checkPermission(DEVICE_READ);
+        return store.getAvailableDeviceCount();
+    }
+
     @Override
     public Iterable<Device> getDevices() {
         checkPermission(DEVICE_READ);

core/net/src/test/java/org/onosproject/net/device/impl/DeviceManagerTest.java

@@ -144,6 +144,7 @@ public class DeviceManagerTest {
         assertNotNull("one device expected", it.next());
         assertFalse("only one device expected", it.hasNext());
         assertEquals("incorrect device count", 1, service.getDeviceCount());
+        assertEquals("incorrect available device count", 1, service.getAvailableDeviceCount());
         assertTrue("device should be available", service.isAvailable(DID1));
     }
 
@@ -165,6 +166,7 @@ public class DeviceManagerTest {
         validateEvents(DEVICE_AVAILABILITY_CHANGED);
 
         assertEquals("incorrect device count", 2, service.getDeviceCount());
+        assertEquals("incorrect available device count", 2, service.getAvailableDeviceCount());
     }
 
     @Test
@@ -225,8 +227,8 @@ public class DeviceManagerTest {
         assertEquals("wrong port count", 2, service.getPorts(DID1).size());
 
         Port port = service.getPort(DID1, P1);
-        assertEquals("incorrect port", P1, service.getPort(DID1, P1).number());
+        assertEquals("incorrect port", P1, port.number());
-        assertEquals("incorrect state", true, service.getPort(DID1, P1).isEnabled());
+        assertEquals("incorrect state", true, port.isEnabled());
     }
 
     @Test
@@ -234,10 +236,12 @@ public class DeviceManagerTest {
         connectDevice(DID1, SW1);
         connectDevice(DID2, SW2);
         assertEquals("incorrect device count", 2, service.getDeviceCount());
+        assertEquals("incorrect available device count", 2, service.getAvailableDeviceCount());
         admin.removeDevice(DID1);
         assertNull("device should not be found", service.getDevice(DID1));
         assertNotNull("device should be found", service.getDevice(DID2));
         assertEquals("incorrect device count", 1, service.getDeviceCount());
+        assertEquals("incorrect available device count", 1, service.getAvailableDeviceCount());
 
     }