org.apache.hadoop.fs.statistics.impl.DynamicIOStatistics Maven / Gradle / Ivy
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* 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.impl;
import java.util.Collections;
import java.util.Map;
import java.util.function.Function;
import org.apache.hadoop.fs.statistics.MeanStatistic;
/**
* These statistics are dynamically evaluated by the supplied
* String -> type functions.
*
* This allows statistic sources to supply a list of callbacks used to
* generate the statistics on demand; similar to some of the Coda Hale metrics.
*
* The evaluation actually takes place during the iteration's {@code next()}
* call.
*/
final class DynamicIOStatistics
extends AbstractIOStatisticsImpl {
/**
* Counter evaluators.
*/
private final EvaluatingStatisticsMap counters
= new EvaluatingStatisticsMap<>();
private final EvaluatingStatisticsMap gauges
= new EvaluatingStatisticsMap<>();
private final EvaluatingStatisticsMap minimums
= new EvaluatingStatisticsMap<>();
private final EvaluatingStatisticsMap maximums
= new EvaluatingStatisticsMap<>();
private final EvaluatingStatisticsMap meanStatistics
= new EvaluatingStatisticsMap<>(MeanStatistic::copy);
DynamicIOStatistics() {
}
@Override
public Map counters() {
return Collections.unmodifiableMap(counters);
}
@Override
public Map gauges() {
return Collections.unmodifiableMap(gauges);
}
@Override
public Map minimums() {
return Collections.unmodifiableMap(minimums);
}
@Override
public Map maximums() {
return Collections.unmodifiableMap(maximums);
}
@Override
public Map meanStatistics() {
return Collections.unmodifiableMap(meanStatistics);
}
/**
* add a mapping of a key to a counter function.
* @param key the key
* @param eval the evaluator
*/
void addCounterFunction(String key, Function eval) {
counters.addFunction(key, eval);
}
/**
* add a mapping of a key to a gauge function.
* @param key the key
* @param eval the evaluator
*/
void addGaugeFunction(String key, Function eval) {
gauges.addFunction(key, eval);
}
/**
* add a mapping of a key to a minimum function.
* @param key the key
* @param eval the evaluator
*/
void addMinimumFunction(String key, Function eval) {
minimums.addFunction(key, eval);
}
/**
* add a mapping of a key to a maximum function.
* @param key the key
* @param eval the evaluator
*/
void addMaximumFunction(String key, Function eval) {
maximums.addFunction(key, eval);
}
/**
* add a mapping of a key to a meanStatistic function.
* @param key the key
* @param eval the evaluator
*/
void addMeanStatisticFunction(String key,
Function eval) {
meanStatistics.addFunction(key, eval);
}
}