com.soteradefense.dga.louvain.mapreduce.LouvainTableSynthesizerReducer.java Source code

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Here is the source code for com.soteradefense.dga.louvain.mapreduce.LouvainTableSynthesizerReducer.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 com.soteradefense.dga.louvain.mapreduce;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class LouvainTableSynthesizerReducer extends Reducer<Text, Text, Text, NullWritable> {

    private static final Logger logger = LoggerFactory.getLogger(LouvainTableSynthesizerReducer.class);

    @Override
    protected void reduce(Text key, Iterable<Text> values, Context context)
            throws IOException, InterruptedException {
        StringBuilder builder = new StringBuilder();
        String rightText = null;
        List<String> zeros = new ArrayList<String>();
        for (Text item : values) {
            String valueItem = item.toString();
            String[] tokens = valueItem.split(":");
            int side;
            try {
                side = Integer.parseInt(tokens[1]);
            } catch (NumberFormatException nfe) {
                throw new NumberFormatException("valueItem: " + valueItem);
            }
            if (side == 1) {
                rightText = tokens[0];
            } else {
                zeros.add(tokens[0]);
            }
        }
        for (String item : zeros) {
            builder.append(item);
            if (rightText != null) {
                builder.append('\t');
                builder.append(rightText);
            }
            context.write(new Text(builder.toString()), NullWritable.get());
            builder.setLength(0);
        }

    }
}