001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.metrics2.lib;
020
021import org.apache.hadoop.classification.InterfaceAudience;
022import org.apache.hadoop.classification.InterfaceStability;
023import org.apache.hadoop.metrics2.MetricsInfo;
024import org.apache.hadoop.metrics2.MetricsRecordBuilder;
025
026import java.util.concurrent.atomic.AtomicLong;
027
028/**
029 * A mutable long counter
030 */
031@InterfaceAudience.Public
032@InterfaceStability.Evolving
033public class MutableCounterLong extends MutableCounter {
034
035  private AtomicLong value = new AtomicLong();
036
037  MutableCounterLong(MetricsInfo info, long initValue) {
038    super(info);
039    this.value.set(initValue);
040  }
041
042  @Override
043  public void incr() {
044    incr(1);
045  }
046
047  /**
048   * Increment the value by a delta
049   * @param delta of the increment
050   */
051  public void incr(long delta) {
052    value.addAndGet(delta);
053    setChanged();
054  }
055
056  public long value() {
057    return value.get();
058  }
059
060  @Override
061  public void snapshot(MetricsRecordBuilder builder, boolean all) {
062    if (all || changed()) {
063      builder.addCounter(info(), value());
064      clearChanged();
065    }
066  }
067
068}