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 gauge
030 */
031@InterfaceAudience.Public
032@InterfaceStability.Evolving
033public class MutableGaugeLong extends MutableGauge {
034
035  private AtomicLong value = new AtomicLong();
036
037  MutableGaugeLong(MetricsInfo info, long initValue) {
038    super(info);
039    this.value.set(initValue);
040  }
041
042  public long value() {
043    return value.get();
044  }
045
046  @Override
047  public void incr() {
048    incr(1);
049  }
050
051  /**
052   * Increment by delta
053   * @param delta of the increment
054   */
055  public void incr(long delta) {
056    value.addAndGet(delta);
057    setChanged();
058  }
059
060  @Override
061  public void decr() {
062    decr(1);
063  }
064
065  /**
066   * decrement by delta
067   * @param delta of the decrement
068   */
069  public void decr(long delta) {
070    value.addAndGet(-delta);
071    setChanged();
072  }
073
074  /**
075   * Set the value of the metric
076   * @param value to set
077   */
078  public void set(long value) {
079    this.value.set(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
091}