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 static com.google.common.base.Preconditions.*;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.metrics2.MetricsInfo;
026
027/**
028 * The mutable gauge metric interface
029 */
030@InterfaceAudience.Public
031@InterfaceStability.Evolving
032public abstract class MutableGauge extends MutableMetric {
033  private final MetricsInfo info;
034
035  protected MutableGauge(MetricsInfo info) {
036    this.info = checkNotNull(info, "metric info");
037  }
038
039  protected MetricsInfo info() {
040    return info;
041  }
042
043  /**
044   * Increment the value of the metric by 1
045   */
046  public abstract void incr();
047
048  /**
049   * Decrement the value of the metric by 1
050   */
051  public abstract void decr();
052}