code: /**
   * Copyright (c) 2010 Yahoo! Inc. All rights reserved.
   *
   * 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. See accompanying
   * LICENSE file.
   */
  
  package com.yahoo.ycsb.measurements;
  
  import com.yahoo.ycsb.Status;
  import com.yahoo.ycsb.measurements.exporter.MeasurementsExporter;
  
  import java.io.IOException;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.AtomicInteger;
  
  /**
   * A single measured metric (such as READ LATENCY)
   */
  public abstract class OneMeasurement {
  
    private final String _name;
    private  final ConcurrentHashMap<Status, AtomicInteger> _returncodes;
  
    public String getName() {
      return _name;
    }
  
    /**
     * @param _name
     */
    public OneMeasurement(String _name) {
      this._name = _name;
      this._returncodes = new ConcurrentHashMap<Status, AtomicInteger>();
    }
  
    public abstract void measure(int latency);
  
    public abstract String getSummary();
  
    /**
     * No need for synchronization, using CHM to deal with that
     */
    public void reportStatus(Status status) {
      AtomicInteger counter = _returncodes.get(status);
  
      if (counter == null) {
        AtomicInteger other = _returncodes.putIfAbsent(status, counter = new AtomicInteger());
        if (other != null) {
          counter = other;
        }
      }
  
      counter.incrementAndGet();
    }
  
    /**
     * Export the current measurements to a suitable format.
     *
     * @param exporter Exporter representing the type of format to write to.
     * @throws IOException Thrown if the export failed.
     */
    public abstract void exportMeasurements(MeasurementsExporter exporter) throws IOException;
  
    protected final void exportStatusCounts(MeasurementsExporter exporter) throws IOException {
      for (Map.Entry<Status, AtomicInteger> entry : _returncodes.entrySet()) {
        exporter.write(getName(), "Return=" + entry.getKey().getName(), entry.getValue().get());
      }
    }
  }
  