[ONOS-6806] Add getAvailableDeviceCount method to DeviceService

Change-Id: Ieda7e66c1a1d25aa92b55542ecfe59652dac3bc5
diff --git a/core/api/src/main/java/org/onosproject/net/device/DeviceService.java b/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
index 1cb90e8..b1ab0e6 100644
--- a/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
+++ b/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
@@ -39,6 +39,15 @@
     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.
      *