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