org.apache.hadoop.fs.statistics.IOStatistics Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.fs.statistics;
import java.util.Map;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* IO Statistics.
*
* These are low-cost per-instance statistics provided by any Hadoop
* I/O class instance.
*
* Consult the filesystem specification document for the requirements
* of an implementation of this interface.
*/
@InterfaceAudience.Public
@InterfaceStability.Unstable
public interface IOStatistics {
/**
* Map of counters.
* @return the current map of counters.
*/
Map counters();
/**
* Map of gauges.
* @return the current map of gauges.
*/
Map gauges();
/**
* Map of minimums.
* @return the current map of minimums.
*/
Map minimums();
/**
* Map of maximums.
* @return the current map of maximums.
*/
Map maximums();
/**
* Map of meanStatistics.
* @return the current map of MeanStatistic statistics.
*/
Map meanStatistics();
/**
* Value when a minimum value has never been set.
*/
long MIN_UNSET_VALUE = -1;
/**
* Value when a max value has never been set.
*/
long MAX_UNSET_VALUE = -1;
}