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 gauge
028 */
029@InterfaceAudience.Public
030@InterfaceStability.Evolving
031public class MutableGaugeInt extends MutableGauge {
032
033  private volatile int value;
034
035  MutableGaugeInt(MetricsInfo info, int initValue) {
036    super(info);
037    this.value = initValue;
038  }
039
040  public int value() {
041    return value;
042  }
043
044  @Override
045  public synchronized void incr() {
046    ++value;
047    setChanged();
048  }
049
050  /**
051   * Increment by delta
052   * @param delta of the increment
053   */
054  public synchronized void incr(int delta) {
055    value += delta;
056    setChanged();
057  }
058
059  @Override
060  public synchronized void decr() {
061    --value;
062    setChanged();
063  }
064
065  /**
066   * decrement by delta
067   * @param delta of the decrement
068   */
069  public synchronized void decr(int delta) {
070    value -= delta;
071    setChanged();
072  }
073
074  /**
075   * Set the value of the metric
076   * @param value to set
077   */
078  public void set(int value) {
079    this.value = value;
080    setChanged();
081  }
082
083  @Override
084  public void snapshot(MetricsRecordBuilder builder, boolean all) {
085    if (all || changed()) {
086      builder.addGauge(info(), value);
087      clearChanged();
088    }
089  }
090}