Add MetricsServiceAdapter for unit test

Change-Id: I5210e14c7cd6e462d750046f5557371ba7d29f15

+/*
+ * Copyright 2014-2015 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.
+ */
+package org.onlab.metrics;
+
+
+import com.codahale.metrics.Counter;
+import com.codahale.metrics.Histogram;
+import com.codahale.metrics.Meter;
+import com.codahale.metrics.Timer;
+import com.codahale.metrics.Gauge;
+import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricFilter;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * Test adapter for metrics service.
+ */
+public class MetricsServiceAdapter implements MetricsService {
+
+    @Override
+    public MetricsComponent registerComponent(String name) {
+        MetricsComponent metricsComponent = new MetricsComponent(name);
+        return metricsComponent;
+    }
+
+    @Override
+    public Counter createCounter(MetricsComponent component,
+                                 MetricsFeature feature, String metricName) {
+        return null;
+    }
+
+    @Override
+    public Histogram createHistogram(MetricsComponent component,
+                                     MetricsFeature feature, String metricName) {
+        return null;
+    }
+
+    @Override
+    public Timer createTimer(MetricsComponent component,
+                             MetricsFeature feature, String metricName) {
+        return null;
+    }
+
+    @Override
+    public Meter createMeter(MetricsComponent component,
+                             MetricsFeature feature, String metricName) {
+        return null;
+    }
+
+    @Override
+    public <T extends Metric> T registerMetric(MetricsComponent component,
+                                               MetricsFeature feature, String metricName, T metric) {
+        return null;
+    }
+
+    @Override
+    public boolean removeMetric(MetricsComponent component,
+                                MetricsFeature feature, String metricName) {
+        return false;
+    }
+
+    @Override
+    public Map<String, Timer> getTimers(MetricFilter filter) {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public Map<String, Gauge> getGauges(MetricFilter filter) {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public Map<String, Counter> getCounters(MetricFilter filter) {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public Map<String, Meter> getMeters(MetricFilter filter) {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public Map<String, Histogram> getHistograms(MetricFilter filter) {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public Map<String, Metric> getMetrics() {
+        return Collections.emptyMap();
+    }
+
+    @Override
+    public void removeMatching(MetricFilter filter) {
+    }
+}