/**
* 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.mahout.math.stats.entropy;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.common.StringTuple;
import org.apache.mahout.math.VarIntWritable;
import java.io.IOException;
/**
* Groups the input by key and value. Therefore it merges both to one key of type {@link StringTuple} and emits
* {@link VarIntWritable}(1) as value.
*/
public final class GroupAndCountByKeyAndValueMapper extends Mapper<Text, Text, StringTuple, VarIntWritable> {
private static final VarIntWritable ONE = new VarIntWritable(1);
@Override
protected void map(Text key, Text value, Context context) throws IOException, InterruptedException {
StringTuple tuple = new StringTuple(key.toString());
tuple.add(value.toString());
context.write(tuple, ONE);
}
}