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/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
index 02f65e4..faf7e50 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
@@ -998,6 +998,16 @@
     }
 
     @Override
+    public PortStatistics getStatisticsForPort(DeviceId deviceId, PortNumber portNumber) {
+        Map<PortNumber, PortStatistics> portStatsMap = devicePortStats.get(deviceId);
+        if (portStatsMap == null) {
+            return null;
+        }
+        PortStatistics portStats = portStatsMap.get(portNumber);
+        return portStats;
+    }
+
+    @Override
     public List<PortStatistics> getPortDeltaStatistics(DeviceId deviceId) {
         Map<PortNumber, PortStatistics> portStats = devicePortDeltaStats.get(deviceId);
         if (portStats == null) {
@@ -1007,6 +1017,16 @@
     }
 
     @Override
+    public PortStatistics getDeltaStatisticsForPort(DeviceId deviceId, PortNumber portNumber) {
+        Map<PortNumber, PortStatistics> portStatsMap = devicePortDeltaStats.get(deviceId);
+        if (portStatsMap == null) {
+            return null;
+        }
+        PortStatistics portStats = portStatsMap.get(portNumber);
+        return portStats;
+    }
+
+    @Override
     public Port getPort(DeviceId deviceId, PortNumber portNumber) {
         Map<PortNumber, Port> ports = devicePorts.get(deviceId);
         return ports == null ? null : ports.get(portNumber);