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
026/**
027 * A mutable long counter
028 */
029@InterfaceAudience.Public
030@InterfaceStability.Evolving
031public class MutableCounterLong extends MutableCounter {
032
033  private volatile long value;
034
035  MutableCounterLong(MetricsInfo info, long initValue) {
036    super(info);
037    this.value = initValue;
038  }
039
040  @Override
041  public synchronized void incr() {
042    ++value;
043    setChanged();
044  }
045
046  /**
047   * Increment the value by a delta
048   * @param delta of the increment
049   */
050  public synchronized void incr(long delta) {
051    value += delta;
052    setChanged();
053  }
054
055  public long value() {
056    return value;
057  }
058
059  @Override
060  public void snapshot(MetricsRecordBuilder builder, boolean all) {
061    if (all || changed()) {
062      builder.addCounter(info(), value);
063      clearChanged();
064    }
065  }
066
067}