com.hazelcast.mapreduce.aggregation.impl.DoubleAvgAggregation Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2015, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.mapreduce.aggregation.impl;
import com.hazelcast.mapreduce.Collator;
import com.hazelcast.mapreduce.Combiner;
import com.hazelcast.mapreduce.CombinerFactory;
import com.hazelcast.mapreduce.Mapper;
import com.hazelcast.mapreduce.Reducer;
import com.hazelcast.mapreduce.ReducerFactory;
import com.hazelcast.mapreduce.aggregation.Supplier;
import java.util.Map;
/**
* The predefined average aggregation for values of type double.
*
* @param the input key type
* @param the input value type
*/
public class DoubleAvgAggregation
implements AggType, AvgTuple, Double> {
@Override
public Collator>, Double> getCollator() {
return new Collator>, Double>() {
@Override
public Double collate(Iterable>> values) {
long count = 0;
double amount = 0;
for (Map.Entry> entry : values) {
AvgTuple tuple = entry.getValue();
count += tuple.getFirst();
amount += tuple.getSecond();
}
return amount / count;
}
};
}
@Override
public Mapper getMapper(Supplier supplier) {
return new SupplierConsumingMapper(supplier);
}
@Override
public CombinerFactory> getCombinerFactory() {
return new DoubleAvgCombinerFactory();
}
@Override
public ReducerFactory, AvgTuple> getReducerFactory() {
return new DoubleAvgReducerFactory();
}
/**
* Average CombinerFactory for type double
*
* @param the key type
*/
static final class DoubleAvgCombinerFactory
extends AbstractAggregationCombinerFactory> {
@Override
public Combiner> newCombiner(Key key) {
return new DoubleAvgCombiner();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.DOUBLE_AVG_COMBINER_FACTORY;
}
}
/**
* Average ReducerFactory for type double
*
* @param the key type
*/
static final class DoubleAvgReducerFactory
extends AbstractAggregationReducerFactory, AvgTuple> {
@Override
public Reducer, AvgTuple> newReducer(Key key) {
return new DoubleAvgReducer();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.DOUBLE_AVG_REDUCER_FACTORY;
}
}
/**
* Average Combiner for type double
*/
private static final class DoubleAvgCombiner
extends Combiner> {
private long count;
private double amount;
@Override
public void combine(Double value) {
count++;
amount += value;
}
@Override
public AvgTuple finalizeChunk() {
long count = this.count;
double amount = this.amount;
this.count = 0;
this.amount = 0;
return new AvgTuple(count, amount);
}
}
/**
* Average Reducer for type double
*/
private static final class DoubleAvgReducer
extends Reducer, AvgTuple> {
private long count;
private double amount;
@Override
public void reduce(AvgTuple value) {
count += value.getFirst();
amount += value.getSecond();
}
@Override
public AvgTuple finalizeReduce() {
return new AvgTuple(count, amount);
}
}
}