fixes for Meter Service

Change-Id: I83d5b8a2e0a955c050f7afe96761d5709d4f9f18
diff --git a/core/api/src/main/java/org/onosproject/net/meter/MeterService.java b/core/api/src/main/java/org/onosproject/net/meter/MeterService.java
index eaa2a50..31aa17f 100644
--- a/core/api/src/main/java/org/onosproject/net/meter/MeterService.java
+++ b/core/api/src/main/java/org/onosproject/net/meter/MeterService.java
@@ -17,6 +17,8 @@
 
 import org.onosproject.event.ListenerService;
 
+import java.util.Collection;
+
 /**
  * Service for add/updating and removing meters. Meters are
  * are assigned to flow to rate limit them and provide a certain
@@ -55,6 +57,13 @@
     Meter getMeter(MeterId id);
 
     /**
+     * Fetches all the meters.
+     *
+     * @return a collection of meters
+     */
+    Collection<Meter> getAllMeters();
+
+    /**
      * Allocate a meter id which must be used to create the meter.
      *
      * @return a meter id