public interface SourceOutput<E> extends WatermarkOutput {

	void emitRecord(E record, String splitId);

	void emitRecord(E record, String splitId, long timestamp);
}

/**
 * Emit a record to the downstream.
 *
 * @param <E> the type of the record emitted by the {@link SplitReader}
 * @param <T> the type of records that are eventually emitted to the {@link SourceOutput}.
 * @param <SplitStateT> the mutable type of split state.
 */
public interface RecordEmitter<E, T, SplitStateT> {

	/**
	 * Process and emit the records to the {@link RecordEmitter.OutputSourceOutput}. A few recommendations to the implementation
	 * are following:
	 *
	 * <ul>
	 * 	<li>The method maybe interrupted in the middle. In that case, the same set of records will be passed
	 * 	to the record emitter again later. The implementation needs to make sure it reades
	 * 	<li>
	 * </ul>
	 *
	 * @param element The intermediate element read by the SplitReader.
     * @param splitId The ID of the split the element was consumed from.
	 * @param output The output to which the final records are emit to.
	 * @param splitState The state of the split.
	 */
	void emitRecord(E element, StringSourceOutput<T> splitId, Output<T> output, SplitStateT splitState) throws Exception;

	/**
	 * The interface for RecordEmitter output.
	 *
	 * @param <T> the type of the record emit
	 */
	interface Output<T> {
		/**
		 * Emit an element without a timestamp. Equivalent to {@link #collect(Object, Long) collect(timestamp, null)};
		 *
		 * @param element
		 */
		void collect(T element) throws Exception;

		/**
		 * Emit an element with timestamp.
		 *
		 * @param element
		 * @param timestamp
		 */
		void collect(T element, Long timestamp) throws Exception;
	}
}