/*
* 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.apache.solr.hadoop;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* MR Reducer that randomizing a list of URLs.
*
* Reducer input is (randomPosition, URL) pairs. Each such pair indicates a file
* to index.
*
* Reducer output is a list of URLs, each URL in a random position.
*/
public class LineRandomizerReducer extends Reducer<LongWritable, Text, Text, NullWritable> {
private static final Logger LOGGER = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
@Override
protected void reduce(LongWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
for (Text value : values) {
LOGGER.debug("reduce key: {}, value: {}", key, value);
context.write(value, NullWritable.get());
}
}
}