Delta Port Statistics added to DeviceStore, Device Service and CLI
Changed misspelled word in description of the portstats command switch

Change-Id: I131940c83c5cb12080532a4804ec424ca66afa64
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 c59454d..218ccca 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
@@ -105,6 +105,14 @@
     List<PortStatistics> getPortStatistics(DeviceId deviceId);
 
     /**
+     * Returns the list of port delta statistics associated with the device.
+     *
+     * @param deviceId device identitifer
+     * @return list of port statistics
+     */
+    List<PortStatistics> getPortDeltaStatistics(DeviceId deviceId);
+
+    /**
      * Returns the port with the specified number and hosted by the given device.
      *
      * @param deviceId   device identifier
diff --git a/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java b/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
index f326bb1..d1aa874 100644
--- a/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
+++ b/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
@@ -135,6 +135,14 @@
     List<PortStatistics> getPortStatistics(DeviceId deviceId);
 
     /**
+     * Returns the list of delta port statistics of the specified device.
+     *
+     * @param deviceId
+     * @return list of delta port statistics of all ports of the device
+     */
+    List<PortStatistics> getPortDeltaStatistics(DeviceId deviceId);
+
+    /**
      * Returns the specified device port.
      *
      * @param deviceId   device identifier
@@ -159,5 +167,4 @@
      */
     DeviceEvent removeDevice(DeviceId deviceId);
 
-
 }