hadoop-tools/hadoop-openstack/src/main/java/org/apache/hadoop/fs/swift/util/DurationStatsTable.java

/*
 * 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.fs.swift.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Build a duration stats table to which you can add statistics.
 * Designed to be multithreaded
 */
public class DurationStatsTable {

  private Map<String,DurationStats> statsTable
    = new HashMap<String, DurationStats>(6);

  /**
   * Add an operation
   * @param operation operation name
   * @param duration duration
   */
  public void add(String operation, Duration duration, boolean success) {
    DurationStats durationStats;
    String key = operation;
    if (!success) {
      key += "-FAIL";
    }
    synchronized (this) {
      durationStats = statsTable.get(key);
      if (durationStats == null) {
        durationStats = new DurationStats(key);
        statsTable.put(key, durationStats);
      }
    }
    synchronized (durationStats) {
      durationStats.add(duration);
    }
  }

  /**
   * Get the current duration statistics
   * @return a snapshot of the statistics
   */
   public synchronized List<DurationStats> getDurationStatistics() {
     List<DurationStats> results = new ArrayList<DurationStats>(statsTable.size());
     for (DurationStats stat: statsTable.values()) {
       results.add(new DurationStats(stat));
     }
     return results;
   }

  /**
   * reset the values of the statistics. This doesn't delete them, merely zeroes them.
   */
  public synchronized void reset() {
    for (DurationStats stat : statsTable.values()) {
      stat.reset();
    }
  }
}