Configurable Port Stats Collection interval

Change-Id: I4999338ecf1c608f93b66ba979126b2a5deda165
diff --git a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/PortStatsCollector.java b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/PortStatsCollector.java
index c872a82..8383fa3 100644
--- a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/PortStatsCollector.java
+++ b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/PortStatsCollector.java
@@ -41,7 +41,7 @@
     private final HashedWheelTimer timer = Timer.getTimer();
     private final OpenFlowSwitch sw;
     private final Logger log = getLogger(getClass());
-    private final int refreshInterval;
+    private int refreshInterval;
     private final AtomicLong xidAtomic = new AtomicLong(1);
 
     private Timeout timeout;
@@ -74,6 +74,13 @@
         }
     }
 
+    synchronized void adjustPollInterval(int pollInterval) {
+        this.refreshInterval = pollInterval;
+        // task.cancel();
+        // task = new InternalTimerTask();
+        // timer.scheduleAtFixedRate(task, pollInterval * SECONDS, pollInterval * 1000);
+    }
+
     private void sendPortStatistic() {
         if (sw.getRole() != RoleState.MASTER) {
             return;