net.orpiske.tcs.wc.map.WordMapper.java Source code

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Here is the source code for net.orpiske.tcs.wc.map.WordMapper.java

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/**
 Copyright 2014 Otavio Rodolfo Piske
    
 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 net.orpiske.tcs.wc.map;

import net.orpiske.sfs.filter.dictionary.DictionaryFilter;
import net.orpiske.sfs.filter.runner.DefaultFilterRunner;
import net.orpiske.sfs.filter.runner.FilterRunner;
import net.orpiske.sfs.filter.simple.CharacterFilter;
import net.orpiske.sfs.filter.Filter;
import net.orpiske.sfs.filter.simple.StringSizeFilter;
import net.orpiske.tcs.wc.io.OccurrenceWritable;
import org.apache.cassandra.db.Column;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.log4j.Logger;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.SortedMap;
import java.util.StringTokenizer;

public class WordMapper extends Mapper<ByteBuffer, SortedMap<ByteBuffer, Column>, OccurrenceWritable, IntWritable> {
    private static final Logger logger = Logger.getLogger(WordMapper.class);

    private final static IntWritable one = new IntWritable(1);

    private static final FilterRunner runner;

    static {
        /**
         * Setup an array of filters that we run on each
         * token we analyze
         */
        ArrayList<Filter> filters = new ArrayList<Filter>();

        // To remove anything that it's not a letter
        filters.add(new CharacterFilter());

        // ... and is smaller than 2
        filters.add(new StringSizeFilter(2));

        // ... and it's not an adjective
        filters.add(new DictionaryFilter());

        runner = new DefaultFilterRunner(filters);
    }

    public WordMapper() {
        super();
    }

    private String getColumnValue(SortedMap<ByteBuffer, Column> columns, final String name)
            throws IOException, InterruptedException {
        ByteBuffer byteBuffer = Text.encode(name);

        Column column = columns.get(byteBuffer);

        String ret = ByteBufferUtil.string(column.value());

        return ret;
    }

    /**
     * Runs the map part of the M/R job
     * @param key
     * @param columns
     * @param context
     * @throws IOException
     * @throws InterruptedException
     */
    public void map(ByteBuffer key, SortedMap<ByteBuffer, Column> columns, Context context)
            throws IOException, InterruptedException {
        String referenceText = getColumnValue(columns, "reference_text");

        if (logger.isDebugEnabled()) {
            String keyText = ByteBufferUtil.string(key);

            logger.debug("read " + keyText + " reference_text from cassandra");
        }

        String domainText = getColumnValue(columns, "domain");

        StringTokenizer tokenizer = new StringTokenizer(referenceText);
        while (tokenizer.hasMoreTokens()) {
            String token = tokenizer.nextToken();

            /**
             * We filter the data so that we can ignore IPs, non-words, etc.
             * Please check the code from string-filter-utils for details
             */
            String word = runner.run(token);

            if (!word.isEmpty()) {
                OccurrenceWritable occurrenceWritable = new OccurrenceWritable(domainText, word);

                context.write(occurrenceWritable, one);
            }
        }
    }

}