MergeKeyReducer.java

/**
 * Copyright 2011 Nube Technologies
 *
 * 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 co.nubetech.hiho.merge;

import java.io.IOException;
import java.util.Iterator;

import org.apache.hadoop.mapreduce.Reducer;

import co.nubetech.hiho.dedup.HihoTuple;

public class MergeKeyReducer<K, V> extends Reducer<HihoTuple, HihoValue, K, V> {

	@Override
	public void reduce(HihoTuple hihoTuple, Iterable<HihoValue> hihoValues,
			Context context) throws IOException, InterruptedException {
		context.getCounter(MergeRecordCounter.OUTPUT).increment(1l);
		K key = (K) hihoTuple.getKey();
		
		Iterator<HihoValue> iterator = hihoValues.iterator();
		if (hihoValues == null || hihoValues.equals(null)
				|| !iterator.hasNext()) {
			context.write(key, null);
		} else {
			V val = null;
			HihoValue hihoVal = null;
			while (iterator.hasNext()) {
				hihoVal = iterator.next();
				if (!hihoVal.getIsOld()) {
					val = (V) hihoVal.getVal();
				}
			}
			if (val == null) {
				val = (V) hihoVal.getVal();
			}
			context.write(key, val);

		}
	}
}