content: /*
   * 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.distributedlog.common.stats;
  
  import com.google.common.base.Stopwatch;
  import java.util.concurrent.TimeUnit;
  import org.apache.bookkeeper.common.concurrent.FutureEventListener;
  import org.apache.bookkeeper.stats.OpStatsLogger;
  
  /**
   * A {@link FutureEventListener} monitors the stats for a given operation.
   */
  public class OpStatsListener<T> implements FutureEventListener<T> {
      OpStatsLogger opStatsLogger;
      Stopwatch stopwatch;
  
      public OpStatsListener(OpStatsLogger opStatsLogger, Stopwatch stopwatch) {
          this.opStatsLogger = opStatsLogger;
          if (null == stopwatch) {
              this.stopwatch = Stopwatch.createStarted();
          } else {
              this.stopwatch = stopwatch;
          }
      }
  
      public OpStatsListener(OpStatsLogger opStatsLogger) {
          this(opStatsLogger, null);
      }
  
      @Override
      public void onSuccess(T value) {
          opStatsLogger.registerSuccessfulEvent(stopwatch.elapsed(TimeUnit.MICROSECONDS), TimeUnit.MICROSECONDS);
      }
  
      @Override
      public void onFailure(Throwable cause) {
          opStatsLogger.registerFailedEvent(stopwatch.elapsed(TimeUnit.MICROSECONDS), TimeUnit.MICROSECONDS);
      }
  }
  