org.apache.storm.topology

Class StatefulBoltExecutor<T extends State>

java.lang.Object

org.apache.storm.topology.BaseStatefulBoltExecutor

org.apache.storm.topology.StatefulBoltExecutor<T>

All Implemented Interfaces:

Serializable, IBolt, IComponent, IRichBolt

public class StatefulBoltExecutor<T extends State>
extends BaseStatefulBoltExecutor

Wraps a IStatefulBolt and manages the state of the bolt.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.storm.topology.BaseStatefulBoltExecutor

BaseStatefulBoltExecutor.AnchoringOutputCollector

Constructor Summary

Constructors

Constructor and Description
StatefulBoltExecutor(IStatefulBolt<T> bolt)

Method Summary

Modifier and Type	Method and Description
void	cleanup() Called when an IBolt is going to be shutdown.
void	declareOutputFields(OutputFieldsDeclarer declarer) Declare the output schema for all the streams of this topology.
Map<String,Object>	getComponentConfiguration() Declare configuration specific to this component.
protected void	handleCheckpoint(Tuple checkpointTuple, CheckPointState.Action action, long txid) Sub-classes can implement the logic for handling checkpoint tuple.
protected void	handleTuple(Tuple input) Sub-classes can implement the logic for handling the tuple.
void	prepare(Map stormConf, TopologyContext context, OutputCollector collector) Called when a task for this component is initialized within a worker on the cluster.

Methods inherited from class org.apache.storm.topology.BaseStatefulBoltExecutor

declareCheckpointStream, execute, init

Methods inherited from class java.lang.Object

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

Constructor Detail

StatefulBoltExecutor

public StatefulBoltExecutor(IStatefulBolt<T> bolt)

Method Detail

prepare

public void prepare(Map stormConf,
                    TopologyContext context,
                    OutputCollector collector)

Description copied from interface: IBolt

Called when a task for this component is initialized within a worker on the cluster. It provides the bolt with the environment in which the bolt executes.

This includes the:

Parameters:

stormConf - The Storm configuration for this bolt. This is the configuration provided to the topology merged in with cluster configuration on this machine.

context - This object can be used to get information about this task’s place within the topology, including the task id and component id of this task, input and output information, etc.

collector - The collector is used to emit tuples from this bolt. Tuples can be emitted at any time, including the prepare and cleanup methods. The collector is thread-safe and should be saved as an instance variable of this bolt object.

cleanup

public void cleanup()

Description copied from interface: IBolt

Called when an IBolt is going to be shutdown. There is no guarentee that cleanup will be called, because the supervisor kill -9’s worker processes on the cluster.

The one context where cleanup is guaranteed to be called is when a topology is killed when running Storm in local mode.

declareOutputFields

public void declareOutputFields(OutputFieldsDeclarer declarer)

Description copied from interface: IComponent

Declare the output schema for all the streams of this topology.

Parameters:

declarer - this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream

getComponentConfiguration

public Map<String,Object> getComponentConfiguration()

Description copied from interface: IComponent

Declare configuration specific to this component. Only a subset of the “topology.*” configs can be overridden. The component configuration can be further overridden when constructing the topology using TopologyBuilder

handleCheckpoint

protected void handleCheckpoint(Tuple checkpointTuple,
                                CheckPointState.Action action,
                                long txid)

Description copied from class: BaseStatefulBoltExecutor

Sub-classes can implement the logic for handling checkpoint tuple.

Specified by:

handleCheckpoint in class BaseStatefulBoltExecutor

Parameters:

checkpointTuple - the checkpoint tuple

action - the action (prepare, commit, rollback or initstate)

txid - the transaction id.

handleTuple

protected void handleTuple(Tuple input)

Description copied from class: BaseStatefulBoltExecutor

Sub-classes can implement the logic for handling the tuple.

Specified by:

handleTuple in class BaseStatefulBoltExecutor

Parameters:

input - the input tuple