[ONOS-4127] Backup metric service to ganglia monitoring server

- Initial implementation of metric service reporter
- Unit test for metric service reporter
- Bump up metric lib from 3.1.0 to 3.1.2

Change-Id: Ia178df759d671dfc15cffaacb09d5279ad3d9ad8
diff --git a/apps/metricsreporter/src/main/java/org/onosproject/metrics/reporter/MetricsReporter.java b/apps/metricsreporter/src/main/java/org/onosproject/metrics/reporter/MetricsReporter.java
new file mode 100644
index 0000000..572e45c
--- /dev/null
+++ b/apps/metricsreporter/src/main/java/org/onosproject/metrics/reporter/MetricsReporter.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.metrics.reporter;
+
+/**
+ * A metric report that reports all metrics value to third party monitor.
+ */
+public interface MetricsReporter {
+
+    /**
+     * Starts to report a set of metrics to the monitoring server.
+     */
+    void startReport();
+
+    /**
+     * Stops reporting metrics.
+     */
+    void stopReport();
+}