/**
* Copyright 2005 The Apache Software Foundation
*
* 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 org.apache.nutch.mapReduce.lib;
import java.io.IOException;
import org.apache.nutch.mapReduce.Mapper;
import org.apache.nutch.mapReduce.OutputCollector;
import org.apache.nutch.mapReduce.JobConf;
import org.apache.nutch.io.WritableComparable;
import org.apache.nutch.io.Writable;
import org.apache.nutch.io.LongWritable;
import org.apache.nutch.io.UTF8;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
/** A {@link Mapper} that extracts text matching a regular expression. */
public class RegexMapper implements Mapper {
private Pattern pattern;
private int group;
public void configure(JobConf job) {
pattern = Pattern.compile(job.get("mapred.mapper.regex"));
group = job.getInt("mapred.mapper.regex.group", 0);
}
public void map(WritableComparable key, Writable value,
OutputCollector output) throws IOException {
String text = ((UTF8)value).toString();
Matcher matcher = pattern.matcher(text);
while (matcher.find()) {
output.collect(new UTF8(matcher.group(group)), new LongWritable(1));
}
}
}