TwitterFilterBolt.java

package com.ebottabi.bolt;

/**
 *
 * @author ebot
 */
import java.util.Map;

import twitter4j.HashtagEntity;
import twitter4j.Status;
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
//import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;

public class TwitterFilterBolt extends BaseRichBolt {

    OutputCollector collector;

    @Override
    public void execute(Tuple tuple) {
        Status status = (Status) tuple.getValue(0);

        HashtagEntity hashTags[] = status.getHashtagEntities();
        if (hashTags != null && hashTags.length >= 2) {
            int count = 0;
            /**
             * Do simple filtering to remove spam tweets
             */
            for (HashtagEntity hashtag : hashTags) {
                if ("android".equals(hashtag.getText().toLowerCase())
                        || "androidgames".equals(hashtag.getText().toLowerCase())) {
                    count++;
                }
            }

            if (count == 2) {
                return;
            }

        }

        collector.emit(tuple, new Values(status));
        collector.ack(tuple);
    }

    @Override
    public void cleanup() {
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("FJJ"));
    }

    @Override
    public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
        this.collector = collector;

    }
}