Addressing review comments of patch-3
Addressing review comments of patch-2
Fixing javadoc warnings
Pushing changes for onos-5146 - Added 2 new APIs in DeviceService.java to get port specific PortStatistics by specifying Device ID & Port Number. Also implemented the APIs in SimpleDeviceStore etc. This will be a very useful API for app developers who are intersted to query port specific port statistics

Change-Id: I8f3e5a443eb5b50237a679999311b48609e54a44
diff --git a/core/net/src/main/java/org/onosproject/net/device/impl/DeviceManager.java b/core/net/src/main/java/org/onosproject/net/device/impl/DeviceManager.java
index cd3c543..5b92489 100644
--- a/core/net/src/main/java/org/onosproject/net/device/impl/DeviceManager.java
+++ b/core/net/src/main/java/org/onosproject/net/device/impl/DeviceManager.java
@@ -228,6 +228,22 @@
     }
 
     @Override
+    public PortStatistics getStatisticsForPort(DeviceId deviceId, PortNumber portNumber) {
+        checkPermission(DEVICE_READ);
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        checkNotNull(portNumber, PORT_NUMBER_NULL);
+        return store.getStatisticsForPort(deviceId, portNumber);
+    }
+
+    @Override
+    public PortStatistics getDeltaStatisticsForPort(DeviceId deviceId, PortNumber portNumber) {
+        checkPermission(DEVICE_READ);
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        checkNotNull(portNumber, PORT_NUMBER_NULL);
+        return store.getDeltaStatisticsForPort(deviceId, portNumber);
+    }
+
+    @Override
     public Port getPort(DeviceId deviceId, PortNumber portNumber) {
         checkPermission(DEVICE_READ);
         checkNotNull(deviceId, DEVICE_ID_NULL);