Package com.inductiveautomation.eventstream.gateway.stages.handler

Class HandlerStage

java.lang.Object

com.inductiveautomation.eventstream.gateway.stages.Stage

com.inductiveautomation.eventstream.gateway.stages.handler.HandlerStage

public class HandlerStage
extends Stage

Metrics:
{}.handler-{index}.received (Meter): Total events received
{}.handler-{index}.processTimeNs (Histogram)
{}.handler-{index}.errors (Counter)

Nested Class Summary

Nested classes/interfaces inherited from class com.inductiveautomation.eventstream.gateway.stages.Stage

Stage.ProcessResult, Stage.Subscriber

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ID

Fields inherited from class com.inductiveautomation.eventstream.gateway.stages.Stage

METRIC_ERROR_COUNT, METRIC_PROCESS_TIME, METRIC_QUEUED_EVENT_COUNT, METRIC_RECEIVED, processTimeNs, receivedMeter, STATE_LAST_EMITTED_EVENT_KEY, STATE_LAST_EVENT_KEY, STATE_TEST_KEY

Constructor Summary

Constructors

Constructor	Description
HandlerStage(StageContext context, String subId, HandlerDescriptor descriptor, EventStreamHandler handler, FailureStrategy failureStrategy)

Method Summary

Modifier and Type	Method	Description
static String	generateId(int index)
Map<String,Number>	getMetrics(com.codahale.metrics.Snapshot processTimeNs)
void	onSubscribed()	Called once EventStream subscribers are attached.
CompletableFuture<EventResult>	onUnsubscribe()	Called once EventStream is stopped and before subscribers are detached.
Stage.ProcessResult	process(StageEvent event)	Provides record from previous stage.

Methods inherited from class com.inductiveautomation.eventstream.gateway.stages.Stage

context, errorCount, forward, getDiagnostics, getErrors, getId, getMetrics, getReferenceLocation, getStatus, getTypeId, includeDiagnostics, log, onError, processTimeMostRecent, setIncludeDiagnostics, setStatus, subscribe

Methods inherited from class java.lang.Object

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

Field Details

ID

public static final String ID

See Also:

• Constant Field Values

Constructor Details

HandlerStage

public HandlerStage(StageContext context,
 String subId,
 HandlerDescriptor descriptor,
 EventStreamHandler handler,
 FailureStrategy failureStrategy)

Method Details

generateId

public static String generateId(int index)

getMetrics

public Map<String,Number> getMetrics(com.codahale.metrics.Snapshot processTimeNs)

Overrides:

getMetrics in class Stage

onSubscribed

public void onSubscribed()
                  throws Exception

Description copied from class: Stage

Called once EventStream subscribers are attached. It's safe to begin emitting events at this point.

Overrides:

onSubscribed in class Stage

Throws:

Exception

onUnsubscribe

public CompletableFuture<EventResult> onUnsubscribe()

Description copied from class: Stage

Called once EventStream is stopped and before subscribers are detached.

Overrides:

onUnsubscribe in class Stage

process

public Stage.ProcessResult process(StageEvent event)

Description copied from class: Stage

Provides record from previous stage. It's important to notify a subscriber of action to take (if any) once a record has been processed. Process is always called from the previous stages thread.

Specified by:

process in class Stage

Returns:

ProcessResult determines if processing can continue