WordReader.java

package com.realtimecep.storm.starter.wordcount.spouts;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Map;
import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;

public class WordReader extends BaseRichSpout {

    private SpoutOutputCollector collector;
    private FileReader fileReader;
    private boolean completed = false;
    public void ack(Object msgId) {
        System.out.println("OK:"+msgId);
    }
    public void close() {}
    public void fail(Object msgId) {
        System.out.println("FAIL:"+msgId);
    }

    /**
     * The only thing that the methods will do It is emit each
     * file line
     */
    public void nextTuple() {
        /**
         * The nextuple it is called forever, so if we have been readed the file
         * we will wait and then return
         */
        if(completed){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                //Do nothing
            }
            return;
        }
        String str;
        //Open the reader
        BufferedReader reader = new BufferedReader(fileReader);
        try{
            //Read all lines
            while((str = reader.readLine()) != null){
                /**
                 * By each line emmit a new value with the line as a their
                 */
                this.collector.emit(new Values(str),str);
            }
        }catch(Exception e){
            throw new RuntimeException("Error reading tuple",e);
        }finally{
            completed = true;
        }
    }

    /**
     * We will create the file and get the collector object
     */
    public void open(Map conf, TopologyContext context,
                     SpoutOutputCollector collector) {
        try {
            this.fileReader = new FileReader(conf.get("wordsFile").toString());
        } catch (FileNotFoundException e) {
            throw new RuntimeException("Error reading file ["+conf.get("wordFile")+"]");
        }
        this.collector = collector;
    }

    /**
     * Declare the output field "word"
     */
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("line"));
    }
}