SimpleClockSpout.java

package storm.cookbook.tfidf.spout;

import java.util.Date;
import java.util.List;
import java.util.Map;

import backtype.storm.tuple.Fields;
import backtype.storm.utils.Utils;

/**
 * A simple implementation of {@link ClockSpout} which emits a barebones tick
 * tuple at a fixed rate.
 *
 * Every {@code delay} milliseconds, this spout will emit a tuple containing a
 * single field, {@code tick}, specifying how many tuples have already been
 * emitted.
 *
 * @author Adrian Petrescu <apetresc@gmail.com>
 *
 */
public class SimpleClockSpout extends ClockSpout {
	private final int delay;

	/**
	 * @param streamId
	 *            The stream on which to emit
	 * @param delay
	 *            The fixed amount of time (in milliseconds) between ticks
	 */
	public SimpleClockSpout(String streamId, int delay) {
		super(streamId);
		this.delay = delay;
	}

	@Override
	public List<Object> getTupleForTick(int i) {
		Date now = new Date();
		return Utils.tuple(now.getTime());
	}

	@Override
	public long getDelayForTick(int i) {
		return delay;
	}

	public Fields getOutputFields() {
		return new Fields("tick");
	}

	public Map<String, Object> getComponentConfiguration() {
		return null;
	}
}