nl.utwente.bigdata.TwitterExample.java Source code

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Here is the source code for nl.utwente.bigdata.TwitterExample.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 nl.utwente.bigdata;

import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.Scanner;
import java.util.LinkedList;
import java.lang.String;
import java.lang.Integer;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.hadoop.conf.Configured;

import org.json.simple.parser.JSONParser;

public class TwitterExample {

    public static class ExampleMapper extends Mapper<Object, Text, Text, Text> {
        private String tweetText;
        private String upTweet;
        private JSONParser parser = new JSONParser();
        private Map tweet;
        private LinkedList<String> playerList;

        public void setup(Context context) {
            Path[] playerText;
            try {
                playerText = DistributedCache.getLocalCacheFiles(context.getConfiguration());
                readPlayerFile(playerText[0]);
            } catch (Exception e) {
                System.exit(1);
            }
        }

        private void readPlayerFile(Path playerFile) throws IOException {
            BufferedReader fis = new BufferedReader(new FileReader(playerFile.toString()));
            String player = null;
            playerList = new LinkedList<String>();

            while ((player = fis.readLine()) != null) {
                playerList.add(player);
            }
        }

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {

            try {
                tweet = (Map<String, Object>) parser.parse(value.toString());
            } catch (ClassCastException e) {
                return; // do nothing (we might log this)
            } catch (org.json.simple.parser.ParseException e) {
                return; // do nothing 
            }

            tweetText = (String) tweet.get("text");
            tweetText.replaceAll("\n", " ");

            upTweet = tweetText.toUpperCase();

            for (int i = 0; i < playerList.size(); i++) {
                if (upTweet.indexOf(playerList.get(i)) > -1) {

                    context.write(new Text(playerList.get(i)), new Text("1"));
                }
            }
            // checks whether the tweet mentions a player from the player file
        }
    }

    public static class ExampleReducer extends Reducer<Text, Text, Text, Text> {

        private Text tweetCounter = new Text();

        public void reduce(Text key, Iterable<Text> values, Context context)
                throws IOException, InterruptedException {
            int nrtweets = 0;

            for (Text value : values) {
                nrtweets = nrtweets + 1;
            }

            String strNrTweets = Integer.toString(nrtweets);
            context.write(key, new Text(strNrTweets));
        }
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length < 2) {
            System.err.println("Usage: exampleTwitter <in> [<in>...] <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "Twitter Reader");
        job.addCacheFile(new Path("players.txt").toUri());
        job.setJarByClass(TwitterExample.class);
        job.setMapperClass(ExampleMapper.class);
        job.setReducerClass(ExampleReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        for (int i = 0; i < otherArgs.length - 1; ++i) {
            FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
        }
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[otherArgs.length - 1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}