Add resource name into MetricsDatabase, handle exception gracefully

Change-Id: Icf19965a0fcbfd9696c42b12c32441fd3b161734
diff --git a/apps/cpman/api/src/main/java/org/onosproject/cpman/MetricsDatabase.java b/apps/cpman/api/src/main/java/org/onosproject/cpman/MetricsDatabase.java
index 54167b8..ccdc6b8 100644
--- a/apps/cpman/api/src/main/java/org/onosproject/cpman/MetricsDatabase.java
+++ b/apps/cpman/api/src/main/java/org/onosproject/cpman/MetricsDatabase.java
@@ -30,6 +30,13 @@
     String metricName();
 
     /**
+     * Returns the resource name of this database.
+     *
+     * @return resource name
+     */
+    String resourceName();
+
+    /**
      * Update metric value by specifying metric type.
      *
      * @param metricType    metric type (e.g., load, usage, etc.)
@@ -138,6 +145,14 @@
         Builder withMetricName(String metricName);
 
         /**
+         * Sets the resource name.
+         *
+         * @param resourceName resource name
+         * @return builder object
+         */
+        Builder withResourceName(String resourceName);
+
+        /**
          * Add a new metric to be monitored.
          *
          * @param metricType control metric type