org.apache.storm.topology

Interface IStatefulComponent<T extends State>

All Superinterfaces:

IComponent, Serializable

All Known Subinterfaces:

IStatefulBolt<T>, IStatefulWindowedBolt<T>

All Known Implementing Classes:

BaseStatefulBolt, BaseStatefulWindowedBolt, PersistentWindowedBoltExecutor, StatefulWindowedBoltExecutor, StatefulWordCounter

public interface IStatefulComponent<T extends State>
extends IComponent

Common methods for stateful components in the topology.

A stateful component is one that has state (e.g. the result of some computation in a bolt) and wants the framework to manage its state.

Method Summary

Modifier and Type	Method and Description
void	initState(T state) This method is invoked by the framework with the previously saved state of the component.
void	preCommit(long txid) This is a hook for the component to perform some actions just before the framework commits its state.
void	prePrepare(long txid) This is a hook for the component to perform some actions just before the framework prepares its state.
void	preRollback() This is a hook for the component to perform some actions just before the framework rolls back the prepared state.

Methods inherited from interface org.apache.storm.topology.IComponent

declareOutputFields, getComponentConfiguration

Method Detail

initState

void initState(T state)

This method is invoked by the framework with the previously saved state of the component. This is invoked after prepare but before the component starts processing tuples.

Parameters:

state - the previously saved state of the component.

preCommit

void preCommit(long txid)

This is a hook for the component to perform some actions just before the framework commits its state.

prePrepare

void prePrepare(long txid)

This is a hook for the component to perform some actions just before the framework prepares its state.

preRollback

void preRollback()

This is a hook for the component to perform some actions just before the framework rolls back the prepared state.