/*
    * 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.
   */
  package org.apache.hadoop.hbase.regionserver;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  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;
  
  /**
   * Implementation of {@link MetricsTableQueryMeter} to track query per second for each table in
   * a RegionServer.
   */
  @InterfaceAudience.Private
  public class MetricsTableQueryMeterImpl implements MetricsTableQueryMeter {
    private final Map<TableName, TableMeters> metersByTable = new ConcurrentHashMap<>();
    private final MetricRegistry metricRegistry;
  
    public MetricsTableQueryMeterImpl(MetricRegistry metricRegistry) {
      this.metricRegistry = metricRegistry;
    }
  
    private static class TableMeters {
      final Meter tableReadQueryMeter;
      final Meter tableWriteQueryMeter;
  
      TableMeters(MetricRegistry metricRegistry, TableName tableName) {
        this.tableReadQueryMeter = metricRegistry.meter(qualifyMetricsName(tableName,
          TABLE_READ_QUERY_PER_SECOND));
        this.tableWriteQueryMeter =
          metricRegistry.meter(qualifyMetricsName(tableName, TABLE_WRITE_QUERY_PER_SECOND));
      }
  
      public void updateTableReadQueryMeter(long count) {
        tableReadQueryMeter.mark(count);
      }
  
      public void updateTableReadQueryMeter() {
        tableReadQueryMeter.mark();
      }
  
      public void updateTableWriteQueryMeter(long count) {
        tableWriteQueryMeter.mark(count);
      }
  
      public void updateTableWriteQueryMeter() {
        tableWriteQueryMeter.mark();
      }
    }
  
    private static String qualifyMetricsName(TableName tableName, String metric) {
      StringBuilder sb = new StringBuilder();
      sb.append("Namespace_").append(tableName.getNamespaceAsString());
      sb.append("_table_").append(tableName.getQualifierAsString());
      sb.append("_metric_").append(metric);
      return sb.toString();
    }
  
    private TableMeters getOrCreateTableMeter(TableName tableName) {
      TableMeters meters = metersByTable.get(tableName);
      if (meters == null) {
        meters = new TableMeters(metricRegistry, tableName);
        metersByTable.put(tableName, meters);
      }
      return meters;
    }
  
    @Override
    public void updateTableReadQueryMeter(TableName tableName, long count) {
      getOrCreateTableMeter(tableName).updateTableReadQueryMeter(count);
    }
  
    @Override
    public void updateTableReadQueryMeter(TableName tableName) {
      getOrCreateTableMeter(tableName).updateTableReadQueryMeter();
    }
  
    @Override
    public void updateTableWriteQueryMeter(TableName tableName, long count) {
      getOrCreateTableMeter(tableName).updateTableWriteQueryMeter(count);
    }
  
   @Override
   public void updateTableWriteQueryMeter(TableName tableName) {
     getOrCreateTableMeter(tableName).updateTableWriteQueryMeter();
   }
 }