IntOverwriteAggregator.java

/*
 * 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.openflamingo.mapreduce.aggregator;


import org.apache.hadoop.io.IntWritable;

/**
 * Aggregator that stores a value that is overwritten once another value is
 * aggregated. This aggregator is useful for one-to-many communication from
 * master.compute() or from a special vertex. In case multiple vertices write
 * to this aggregator, its behavior is non-deterministic.
 */
public class IntOverwriteAggregator implements Aggregator<IntWritable> {
	/**
	 * Internal result
	 */
	private int result = 0;

	/**
	 * Aggregate with a primitive integer.
	 *
	 * @param value Integer value to aggregate.
	 */
	public void aggregate(int value) {
		result = value;
	}

	@Override
	public void aggregate(IntWritable value) {
		result = value.get();
	}

	/**
	 * Set aggregated value using a primitive integer.
	 *
	 * @param value Integer value to set.
	 */
	public void setAggregatedValue(int value) {
		result = value;
	}

	@Override
	public void setAggregatedValue(IntWritable value) {
		result = value.get();
	}

	@Override
	public IntWritable getAggregatedValue() {
		return new IntWritable(result);
	}

	@Override
	public IntWritable createAggregatedValue() {
		return new IntWritable();
	}
}