backtype.storm.spout
Class SpoutOutputCollector

java.lang.Object
  backtype.storm.spout.SpoutOutputCollector

All Implemented Interfaces:

ISpoutOutputCollector

public class SpoutOutputCollector
extends Object
implements ISpoutOutputCollector

This output collector exposes the API for emitting tuples from an IRichSpout. The main difference between this output collector and OutputCollector for IRichBolt is that spouts can tag messages with ids so that they can be acked or failed later on. This is the Spout portion of Storm's API to guarantee that each message is fully processed at least once.

Constructor Summary

SpoutOutputCollector(ISpoutOutputCollector delegate)

Method Summary

List<Integer>	emit(List<Object> tuple) Emits a tuple to the default output stream with a null message id.
List<Integer>	emit(List<Object> tuple, Object messageId) Emits a new tuple to the default output stream with the given message ID.
List<Integer>	emit(String streamId, List<Object> tuple) Emits a tuple to the specified output stream with a null message id.
List<Integer>	emit(String streamId, List<Object> tuple, Object messageId) Emits a new tuple to the specified output stream with the given message ID.
void	emitDirect(int taskId, List<Object> tuple) Emits a tuple to the specified task on the default output stream.
void	emitDirect(int taskId, List<Object> tuple, Object messageId) Emits a tuple to the specified task on the default output stream.
void	emitDirect(int taskId, String streamId, List<Object> tuple) Emits a tuple to the specified task on the specified output stream.
void	emitDirect(int taskId, String streamId, List<Object> tuple, Object messageId) Emits a tuple to the specified task on the specified output stream.
void	reportError(Throwable error)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SpoutOutputCollector

public SpoutOutputCollector(ISpoutOutputCollector delegate)

Method Detail

emit

public List<Integer> emit(String streamId,
                          List<Object> tuple,
                          Object messageId)

Emits a new tuple to the specified output stream with the given message ID. When Storm detects that this tuple has been fully processed, or has failed to be fully processed, the spout will receive an ack or fail callback respectively with the messageId as long as the messageId was not null. If the messageId was null, Storm will not track the tuple and no callback will be received. The emitted values must be immutable.

Specified by:

emit in interface ISpoutOutputCollector

Returns:

the list of task ids that this tuple was sent to

emit

public List<Integer> emit(List<Object> tuple,
                          Object messageId)

Emits a new tuple to the default output stream with the given message ID. When Storm detects that this tuple has been fully processed, or has failed to be fully processed, the spout will receive an ack or fail callback respectively with the messageId as long as the messageId was not null. If the messageId was null, Storm will not track the tuple and no callback will be received. The emitted values must be immutable.

Returns:

the list of task ids that this tuple was sent to

emit

public List<Integer> emit(List<Object> tuple)

Emits a tuple to the default output stream with a null message id. Storm will not track this message so ack and fail will never be called for this tuple. The emitted values must be immutable.

emit

public List<Integer> emit(String streamId,
                          List<Object> tuple)

Emits a tuple to the specified output stream with a null message id. Storm will not track this message so ack and fail will never be called for this tuple. The emitted values must be immutable.

emitDirect

public void emitDirect(int taskId,
                       String streamId,
                       List<Object> tuple,
                       Object messageId)

Emits a tuple to the specified task on the specified output stream. This output stream must have been declared as a direct stream, and the specified task must use a direct grouping on this stream to receive the message. The emitted values must be immutable.

Specified by:

emitDirect in interface ISpoutOutputCollector

emitDirect

public void emitDirect(int taskId,
                       List<Object> tuple,
                       Object messageId)

Emits a tuple to the specified task on the default output stream. This output stream must have been declared as a direct stream, and the specified task must use a direct grouping on this stream to receive the message. The emitted values must be immutable.

emitDirect

public void emitDirect(int taskId,
                       String streamId,
                       List<Object> tuple)

Emits a tuple to the specified task on the specified output stream. This output stream must have been declared as a direct stream, and the specified task must use a direct grouping on this stream to receive the message. The emitted values must be immutable.

Because no message id is specified, Storm will not track this message so ack and fail will never be called for this tuple.

emitDirect

public void emitDirect(int taskId,
                       List<Object> tuple)

Emits a tuple to the specified task on the default output stream. This output stream must have been declared as a direct stream, and the specified task must use a direct grouping on this stream to receive the message. The emitted values must be immutable.

Because no message id is specified, Storm will not track this message so ack and fail will never be called for this tuple.

reportError

public void reportError(Throwable error)

Specified by:

reportError in interface ISpoutOutputCollector