/*
* 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.cf.taste.hadoop.pseudo;
import java.io.IOException;
import java.util.regex.Pattern;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.math.VarLongWritable;
/**
* Extracts and emits all user IDs from the users file, or input file.
*/
public final class UserIDsMapper extends
Mapper<LongWritable,Text, VarLongWritable,NullWritable> {
private static final Pattern DELIMITER = Pattern.compile("[\t,]");
@Override
protected void map(LongWritable key,
Text value,
Context context) throws IOException, InterruptedException {
String[] tokens = DELIMITER.split(value.toString());
long userID = Long.parseLong(tokens[0]);
context.write(new VarLongWritable(userID), NullWritable.get());
}
}