IOpaquePartitionedTransactionalSpout.java

package backtype.storm.transactional.partitioned;

import backtype.storm.coordination.BatchOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.IComponent;
import backtype.storm.transactional.TransactionAttempt;
import java.util.Map;

/**
 * This defines a transactional spout which does *not* necessarily replay the
 * same batch every time it emits a batch for a transaction id.
 */
public interface IOpaquePartitionedTransactionalSpout<T> extends IComponent {
	public interface Coordinator {
		/**
		 * Returns true if its ok to emit start a new transaction, false
		 * otherwise (will skip this transaction).
		 * 
		 * You should sleep here if you want a delay between asking for the next
		 * transaction (this will be called repeatedly in a loop).
		 */
		boolean isReady();

		void close();
	}

	public interface Emitter<X> {
		/**
		 * Emit a batch of tuples for a partition/transaction.
		 * 
		 * Return the metadata describing this batch that will be used as
		 * lastPartitionMeta for defining the parameters of the next batch.
		 */
		X emitPartitionBatch(TransactionAttempt tx,
				BatchOutputCollector collector, int partition,
				X lastPartitionMeta);

		int numPartitions();

		void close();
	}

	Emitter<T> getEmitter(Map conf, TopologyContext context);

	Coordinator getCoordinator(Map conf, TopologyContext context);
}