org.apache.mahout.utils.regex.RegexMapper.java Source code

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Here is the source code for org.apache.mahout.utils.regex.RegexMapper.java

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/*
 * 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.utils.regex;

import com.google.common.collect.Lists;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.lucene.analysis.Analyzer;
import org.apache.mahout.common.ClassUtils;

import java.io.IOException;
import java.util.List;
import java.util.regex.Pattern;

public class RegexMapper extends Mapper<LongWritable, Text, LongWritable, Text> {

    public static final String REGEX = "regex";
    public static final String GROUP_MATCHERS = "regex.groups";
    public static final String TRANSFORMER_CLASS = "transformer.class";
    public static final String FORMATTER_CLASS = "formatter.class";

    private Pattern regex;
    private List<Integer> groupsToKeep;
    private RegexTransformer transformer = RegexUtils.IDENTITY_TRANSFORMER;
    private RegexFormatter formatter = RegexUtils.IDENTITY_FORMATTER;
    public static final String ANALYZER_NAME = "analyzerName";

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        groupsToKeep = Lists.newArrayList();
        Configuration config = context.getConfiguration();
        String regexStr = config.get(REGEX);
        regex = Pattern.compile(regexStr);
        String[] groups = config.getStrings(GROUP_MATCHERS);
        if (groups != null) {
            for (String group : groups) {
                groupsToKeep.add(Integer.parseInt(group));
            }
        }

        transformer = ClassUtils.instantiateAs(config.get(TRANSFORMER_CLASS, IdentityTransformer.class.getName()),
                RegexTransformer.class);
        String analyzerName = config.get(ANALYZER_NAME);
        if (analyzerName != null && transformer instanceof AnalyzerTransformer) {
            Analyzer analyzer = ClassUtils.instantiateAs(analyzerName, Analyzer.class);
            ((AnalyzerTransformer) transformer).setAnalyzer(analyzer);
        }

        formatter = ClassUtils.instantiateAs(config.get(FORMATTER_CLASS, IdentityFormatter.class.getName()),
                RegexFormatter.class);
    }

    @Override
    protected void map(LongWritable key, Text text, Context context) throws IOException, InterruptedException {
        String result = RegexUtils.extract(text.toString(), regex, groupsToKeep, " ", transformer);
        if (result != null && !result.isEmpty()) {
            String format = formatter.format(result);
            context.write(key, new Text(format));
        }
    }
}