com.hazelcast.mapreduce.aggregation.impl.IntegerMinAggregation Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2013, 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 minimum aggregation for values of type integer.
*
* @param the input key type
* @param the input value type
*/
public class IntegerMinAggregation
implements AggType {
@Override
public Collator, Integer> getCollator() {
return new Collator, Integer>() {
@Override
public Integer collate(Iterable> values) {
int min = Integer.MAX_VALUE;
for (Map.Entry entry : values) {
int value = entry.getValue();
if (value < min) {
min = value;
}
}
return min;
}
};
}
@Override
public Mapper getMapper(Supplier supplier) {
return new SupplierConsumingMapper(supplier);
}
@Override
public CombinerFactory getCombinerFactory() {
return new IntegerMinCombinerFactory();
}
@Override
public ReducerFactory getReducerFactory() {
return new IntegerMinReducerFactory();
}
/**
* Minimum CombinerFactory for type integer
*
* @param the key type
*/
static final class IntegerMinCombinerFactory
extends AbstractAggregationCombinerFactory {
@Override
public Combiner newCombiner(Key key) {
return new IntegerMinCombiner();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.INTEGER_MIN_COMBINER_FACTORY;
}
}
/**
* Minimum ReducerFactory for type integer
*
* @param the key type
*/
static final class IntegerMinReducerFactory
extends AbstractAggregationReducerFactory {
@Override
public Reducer newReducer(Key key) {
return new IntegerMinReducer();
}
@Override
public int getId() {
return AggregationsDataSerializerHook.INTEGER_MIN_REDUCER_FACTORY;
}
}
/**
* Minimum Combiner for type integer
*/
private static final class IntegerMinCombiner
extends Combiner {
private int chunkMin = Integer.MAX_VALUE;
@Override
public void combine(Integer value) {
if (value < chunkMin) {
chunkMin = value;
}
}
@Override
public Integer finalizeChunk() {
int value = chunkMin;
chunkMin = Integer.MAX_VALUE;
return value;
}
}
/**
* Minimum Reducer for type integer
*/
private static final class IntegerMinReducer
extends Reducer {
private volatile int min = Integer.MAX_VALUE;
@Override
public void reduce(Integer value) {
if (value < min) {
min = value;
}
}
@Override
public Integer finalizeReduce() {
return min;
}
}
}