[ONOS-5934] MeterId availability after withdraw.

Change-Id: Ib40b3ca53bae48d16ecbed9665a4061dd2f7eb0c
diff --git a/core/api/src/main/java/org/onosproject/net/meter/MeterStore.java b/core/api/src/main/java/org/onosproject/net/meter/MeterStore.java
index 5a5016e..a63d272 100644
--- a/core/api/src/main/java/org/onosproject/net/meter/MeterStore.java
+++ b/core/api/src/main/java/org/onosproject/net/meter/MeterStore.java
@@ -114,4 +114,14 @@
      */
     long getMaxMeters(MeterFeaturesKey key);
 
+    /**
+     * Returns the first available MeterId from previously removed meter.
+     * This method allows allocating MeterIds below the actual meterIdCounter
+     * value.
+     *
+     * @param deviceId the device id
+     * @return the meter Id or null if none exist
+     */
+    MeterId firstReusableMeterId(DeviceId deviceId);
+
 }