HBASE-22975 Add read and write QPS metrics at server level and table level

Author: ZhaoBQ

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsTableQPS.java

@@ -6,28 +6,28 @@ public interface MetricsTableQPS {
   String TABLE_WRITE_QPS = "tableWriteQPS";
 
   /**
-   *
-   * @param tableName
-   * @param count
+   * Update table read QPS
+   * @param tableName The table the metric is for
+   * @param count Number of occurrences to record
    */
   void updateTableReadQPS(String tableName, long count);
 
   /**
-   *
-   * @param tableName
+   * Update table read QPS
+   * @param tableName The table the metric is for
    */
   void updateTableReadQPS(String tableName);
 
   /**
-   *
-   * @param tableName
-   * @param count
+   * Update table write QPS
+   * @param tableName The table the metric is for
+   * @param count Number of occurrences to record
    */
   void updateTableWriteQPS(String tableName, long count);
 
   /**
-   *
-   * @param tableName
+   * Update table write QPS
+   * @param tableName The table the metric is for
    */
   void updateTableWriteQPS(String tableName);
 }

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsTableQPSImpl.java

@@ -1,13 +1,13 @@
 package org.apache.hadoop.hbase.regionserver;
 
+import java.util.concurrent.ConcurrentHashMap;
+
 import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.metrics.Meter;
 import org.apache.hadoop.hbase.metrics.MetricRegistry;
 
-import java.util.concurrent.ConcurrentHashMap;
-
 @InterfaceAudience.Private
 public class MetricsTableQPSImpl implements MetricsTableQPS {