Import the DroppedMessageMetrics from origin

This patch import the DroppedMessageMetrics from origin, as oppose to
origin, it does not run timers but relay on the Messaging sevice.

This save the timer and API call for each of the Verb.

Signed-off-by: Amnon Heiman <amnon@scylladb.com>

src/main/java/org/apache/cassandra/metrics/DroppedMessageMetrics.java

@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+/*
+ * Copyright (C) 2015 ScyllaDB
+ */
+/*
+ * Moddified by ScyllaDB
+ */
+
+package org.apache.cassandra.metrics;
+
+import java.util.concurrent.TimeUnit;
+
+import org.apache.cassandra.net.MessagingService;
+
+import com.cloudius.urchin.metrics.APIMetrics;
+import com.cloudius.urchin.metrics.DefaultNameFactory;
+import com.cloudius.urchin.metrics.MetricNameFactory;
+import com.yammer.metrics.core.APISettableMeter;
+
+/**
+ * Metrics for dropped messages by verb.
+ */
+public class DroppedMessageMetrics {
+    /** Number of dropped messages */
+    public final APISettableMeter dropped;
+
+    private long lastDropped = 0;
+
+    public DroppedMessageMetrics(MessagingService.Verb verb) {
+        MetricNameFactory factory = new DefaultNameFactory("DroppedMessage",
+                verb.toString());
+        dropped = (APISettableMeter) APIMetrics.newSettableMeter(
+                factory.createMetricName("Dropped"), "dropped",
+                TimeUnit.SECONDS);
+        dropped.stop();
+    }
+
+    @Deprecated
+    public int getRecentlyDropped() {
+        long currentDropped = dropped.count();
+        long recentlyDropped = currentDropped - lastDropped;
+        lastDropped = currentDropped;
+        return (int) recentlyDropped;
+    }
+
+    public APISettableMeter getMeter() {
+        return dropped;
+    }
+}