Setting up monitoring of cluster communcation service

Change-Id: I771b23db6920b26b592abc5d5156e9d77cde4f00
diff --git a/core/common/src/main/java/org/onosproject/utils/MeteringAgent.java b/core/common/src/main/java/org/onosproject/utils/MeteringAgent.java
new file mode 100644
index 0000000..e3877e8
--- /dev/null
+++ b/core/common/src/main/java/org/onosproject/utils/MeteringAgent.java
@@ -0,0 +1,134 @@
+/*
+ * 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.utils;
+
+import com.codahale.metrics.Counter;
+import com.codahale.metrics.Timer;
+import com.google.common.collect.Maps;
+import org.onlab.metrics.MetricsComponent;
+import org.onlab.metrics.MetricsFeature;
+import org.onlab.metrics.MetricsService;
+import org.onlab.osgi.DefaultServiceDirectory;
+
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Agent that implements usage and performance monitoring via the metrics service.
+ */
+public class MeteringAgent {
+
+    private Counter exceptionCounter;
+    private Counter perObjExceptionCounter;
+    private MetricsService metricsService;
+    private MetricsComponent metricsComponent;
+    private MetricsFeature metricsFeature;
+    private final Map<String, Timer> perObjOpTimers = Maps.newConcurrentMap();
+    private final Map<String, Timer> perOpTimers = Maps.newConcurrentMap();
+    private Timer perPrimitiveTimer;
+    private Timer perObjTimer;
+    private MetricsFeature wildcard;
+    private final boolean activated;
+    private Context nullTimer;
+
+    /**
+     * Constructs a new MeteringAgent for a given distributed primitive.
+     * Instantiates the metrics service
+     * Initializes all the general metrics for that object
+     *
+     * @param primitiveName Type of primitive to be metered
+     * @param objName Global name of the primitive
+     * @param activated boolean flag for whether metering is enabled or not
+     */
+    public MeteringAgent(String primitiveName, String objName, boolean activated) {
+        checkNotNull(objName, "Object name cannot be null");
+        this.activated = activated;
+        nullTimer = new Context(null, "");
+        if (this.activated) {
+            this.metricsService = DefaultServiceDirectory.getService(MetricsService.class);
+            this.metricsComponent = metricsService.registerComponent(primitiveName);
+            this.metricsFeature = metricsComponent.registerFeature(objName);
+            this.wildcard = metricsComponent.registerFeature("*");
+            this.perObjTimer = metricsService.createTimer(metricsComponent, metricsFeature, "*");
+            this.perPrimitiveTimer = metricsService.createTimer(metricsComponent, wildcard, "*");
+            this.perObjExceptionCounter = metricsService.createCounter(metricsComponent, metricsFeature, "exceptions");
+            this.exceptionCounter = metricsService.createCounter(metricsComponent, wildcard, "exceptions");
+        }
+    }
+
+    /**
+     * Initializes a specific timer for a given operation.
+     *
+     * @param op Specific operation being metered
+     * @return timer context
+     */
+    public Context startTimer(String op) {
+        if (!activated) {
+            return nullTimer;
+        }
+        // Check if timer exists, if it doesn't creates it
+        final Timer currTimer = perObjOpTimers.computeIfAbsent(op, timer ->
+                metricsService.createTimer(metricsComponent, metricsFeature, op));
+        perOpTimers.computeIfAbsent(op, timer -> metricsService.createTimer(metricsComponent, wildcard, op));
+        // Starts timer
+        return new Context(currTimer.time(), op);
+    }
+
+    /**
+     * Timer.Context with a specific operation.
+     */
+    public class Context {
+        private final Timer.Context context;
+        private final String operation;
+
+        /**
+         * Constructs Context.
+         *
+         * @param context context
+         * @param operation operation name
+         */
+        public Context(Timer.Context context, String operation) {
+            this.context = context;
+            this.operation = operation;
+        }
+
+        /**
+         * Stops timer given a specific context and updates all related metrics.
+         * @param e throwable
+         */
+        public void stop(Throwable e) {
+            if (!activated) {
+                return;
+            }
+            if (e == null) {
+                //Stop and updates timer with specific measurements per map, per operation
+                final long time = context.stop();
+                //updates timer with aggregated measurements per map
+                perOpTimers.get(operation).update(time, TimeUnit.NANOSECONDS);
+                //updates timer with aggregated measurements per map
+                perObjTimer.update(time, TimeUnit.NANOSECONDS);
+                //updates timer with aggregated measurements per all Consistent Maps
+                perPrimitiveTimer.update(time, TimeUnit.NANOSECONDS);
+            } else {
+                exceptionCounter.inc();
+                perObjExceptionCounter.inc();
+            }
+        }
+    }
+
+}
diff --git a/core/common/src/main/java/org/onosproject/utils/package-info.java b/core/common/src/main/java/org/onosproject/utils/package-info.java
new file mode 100644
index 0000000..570b384
--- /dev/null
+++ b/core/common/src/main/java/org/onosproject/utils/package-info.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2015 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.
+ */
+
+/**
+ * Miscellaneous common facilities used for construction of various core and
+ * app subsystems.
+ */
+package org.onosproject.utils;
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