co.cask.cdap.etl.api.realtime

Class RealtimeSource<T>

java.lang.Object

co.cask.cdap.etl.api.realtime.RealtimeSource<T>

Type Parameters:

T - Type of object that the source emits

All Implemented Interfaces:

Destroyable, PipelineConfigurable, StageLifecycle<RealtimeContext>

@Beta
public abstract class RealtimeSource<T>
extends Object
implements PipelineConfigurable, StageLifecycle<RealtimeContext>

Realtime Source.

Field Summary

Fields

Modifier and Type	Field and Description
static String	PLUGIN_TYPE

Constructor Summary

Constructors

Constructor and Description
RealtimeSource()

Method Summary

Methods

Modifier and Type	Method and Description
void	configurePipeline(PipelineConfigurer pipelineConfigurer) Configure an ETL pipeline, adding datasets and streams that the stage needs.
void	destroy() Destroy the Source.
void	initialize(RealtimeContext context) Initialize the Source.
abstract SourceState	poll(Emitter<T> writer, SourceState currentState) Poll for new data.

Methods inherited from class java.lang.Object

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

Field Detail

PLUGIN_TYPE

public static final String PLUGIN_TYPE

See Also:

Constant Field Values

Constructor Detail

RealtimeSource

public RealtimeSource()

Method Detail

configurePipeline

public void configurePipeline(PipelineConfigurer pipelineConfigurer)

Description copied from interface: PipelineConfigurable

Configure an ETL pipeline, adding datasets and streams that the stage needs.

Specified by:

configurePipeline in interface PipelineConfigurable

Parameters:

pipelineConfigurer - the configurer used to add required datasets and streams

initialize

public void initialize(RealtimeContext context)
                throws Exception

Initialize the Source. This method is guaranteed to be invoked before any calls to poll(co.cask.cdap.etl.api.Emitter<T>, co.cask.cdap.etl.api.realtime.SourceState) are made.

Specified by:

initialize in interface StageLifecycle<RealtimeContext>

Parameters:

context - RealtimeContext

Throws:

Exception - if there is any error during initialization

poll

@Nullable
public abstract SourceState poll(Emitter<T> writer,
                        SourceState currentState)
                          throws Exception

Poll for new data.

Parameters:

writer - Emitter

currentState - SourceState current state of the source

Returns:

SourceState state of the source after poll, will be persisted when all data from poll are processed

Throws:

Exception - if there's an error during this method invocation

destroy

public void destroy()

Destroy the Source.

Specified by:

destroy in interface Destroyable