/*
* Copyright (c) 2008-2017, 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 com.hazelcast.nio.serialization.BinaryInterface;
import java.util.Map;
/**
* The predefined average aggregation for values of type long.
*
* @param <Key> the input key type
* @param <Value> the input value type
*/
public class LongAvgAggregation<Key, Value>
implements AggType<Key, Value, Key, Long, AvgTuple<Long, Long>, AvgTuple<Long, Long>, Long> {
@Override
public Collator<Map.Entry<Key, AvgTuple<Long, Long>>, Long> getCollator() {
return new Collator<Map.Entry<Key, AvgTuple<Long, Long>>, Long>() {
@Override
public Long collate(Iterable<Map.Entry<Key, AvgTuple<Long, Long>>> values) {
long count = 0;
long amount = 0;
for (Map.Entry<Key, AvgTuple<Long, Long>> entry : values) {
AvgTuple<Long, Long> tuple = entry.getValue();
count += tuple.getFirst();
amount += tuple.getSecond();
}
return (long) ((double) amount / count);
}
};
}
@Override
public Mapper<Key, Value, Key, Long> getMapper(Supplier<Key, Value, Long> supplier) {
return new SupplierConsumingMapper<Key, Value, Long>(supplier);
}
@Override
public CombinerFactory<Key, Long, AvgTuple<Long, Long>> getCombinerFactory() {
return new LongAvgCombinerFactory<Key>();
}
@Override
public ReducerFactory<Key, AvgTuple<Long, Long>, AvgTuple<Long, Long>> getReducerFactory() {
return new LongAvgReducerFactory<Key>();
}
/**
* Average CombinerFactory for type long
*
* @param <Key> the key type
*/
@BinaryInterface
static final class LongAvgCombinerFactory<Key>
extends AbstractAggregationCombinerFactory<Key, Long, AvgTuple<Long, Long>> {
@Override
public Combiner<Long, AvgTuple<Long, Long>> newCombiner(Key key) {
return new LongAvgCombiner();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.LONG_AVG_COMBINER_FACTORY;
}
}
/**
* Average ReducerFactory for type long
*
* @param <Key> the key type
*/
@BinaryInterface
static final class LongAvgReducerFactory<Key>
extends AbstractAggregationReducerFactory<Key, AvgTuple<Long, Long>, AvgTuple<Long, Long>> {
@Override
public Reducer<AvgTuple<Long, Long>, AvgTuple<Long, Long>> newReducer(Key key) {
return new LongAvgReducer();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.LONG_AVG_REDUCER_FACTORY;
}
}
/**
* Average Combiner for type long
*/
private static final class LongAvgCombiner
extends Combiner<Long, AvgTuple<Long, Long>> {
private long count;
private long amount;
@Override
public void combine(Long value) {
count++;
amount += value;
}
@Override
public AvgTuple<Long, Long> finalizeChunk() {
long count = this.count;
long amount = this.amount;
this.count = 0;
this.amount = 0;
return new AvgTuple<Long, Long>(count, amount);
}
}
/**
* Average Reducer for type long
*/
private static final class LongAvgReducer
extends Reducer<AvgTuple<Long, Long>, AvgTuple<Long, Long>> {
private long count;
private long amount;
@Override
public void reduce(AvgTuple<Long, Long> value) {
count += value.getFirst();
amount += value.getSecond();
}
@Override
public AvgTuple<Long, Long> finalizeReduce() {
return new AvgTuple<Long, Long>(count, amount);
}
}
}