TickSpout.java

package org.calrissian.flowbox.spout;

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;

import java.util.Map;

public class TickSpout extends BaseRichSpout{

    private long sleepMillis;
    private SpoutOutputCollector collector;

    public TickSpout(long sleepMillis) {
        this.sleepMillis = sleepMillis;
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
        outputFieldsDeclarer.declareStream("tick", new Fields());
    }

    @Override
    public void open(Map map, TopologyContext topologyContext, SpoutOutputCollector spoutOutputCollector) {
        this.collector = spoutOutputCollector;
    }

    @Override
    public void nextTuple() {
        collector.emit("tick", new Values());
        try {
            Thread.sleep(sleepMillis);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
}