org.apache.beam.sdk.extensions.ordered

Interface MutableState<EventT,ResultT>

All Superinterfaces:

java.io.Serializable

public interface MutableState<EventT,ResultT>
extends java.io.Serializable

Mutable state mutates when events apply to it. It is stored in a Beam state.

Method Summary

Modifier and Type	Method and Description
void	mutate(EventT event) The interface assumes that events will mutate the state without the possibility of throwing an error.
ResultT	produceResult() This method is called after each state mutation.

Method Detail

mutate

void mutate(EventT event)
     throws java.lang.Exception

The interface assumes that events will mutate the state without the possibility of throwing an error.

Parameters:

event - to be processed

Throws:

java.lang.Exception - if a checked exception is thrown, the event will be output into OrderedEventProcessorResult.unprocessedEvents() with

produceResult

ResultT produceResult()

This method is called after each state mutation.

Returns:

Result of the processing. Can be null if nothing needs to be output after this mutation.