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}