Package org.axonframework.messaging.eventhandling.processing.streaming.segmenting

Class SequencingEventHandlingComponent

java.lang.Object

org.axonframework.messaging.eventhandling.DelegatingEventHandlingComponent

org.axonframework.messaging.eventhandling.processing.streaming.segmenting.SequencingEventHandlingComponent

All Implemented Interfaces:

DescribableComponent, MessageHandler, EventHandler, EventHandlingComponent

@Internal
public class SequencingEventHandlingComponent
extends DelegatingEventHandlingComponent

An EventHandlingComponent wrapper that ensures events with the same sequence identifier are handled sequentially.

This component uses the ProcessingContext to track the last invocation for each sequence identifier. When a new event arrives, it checks if there's an ongoing process for its sequence identifier. If so, it chains the new event's handling to occur after the previous one completes. If not, it handles the event immediately.

This class is marked as Internal, as users are not expected to interact with it directly. Instead, EventProcessors will wrap an EventHandlingComponent in this component to preserve the ordering.

Since:

5.0.0

Author:

Allard Buijze, Mateusz Nowak, Steven van Beelen

Field Summary

Fields inherited from class org.axonframework.messaging.eventhandling.DelegatingEventHandlingComponent

delegate

Constructor Summary

Constructors

Constructor	Description
SequencingEventHandlingComponent(EventHandlingComponent delegate)	Constructs the component with given delegate to receive calls.

Method Summary

Modifier and Type	Method	Description
MessageStream.Empty<Message>	handle(EventMessage event, ProcessingContext context)	Handles the given event within the given context.

Methods inherited from class org.axonframework.messaging.eventhandling.DelegatingEventHandlingComponent

describeTo, sequenceIdentifierFor, supportedEvents, supports

Methods inherited from class java.lang.Object

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

Constructor Details

SequencingEventHandlingComponent

public SequencingEventHandlingComponent(@Nonnull
 EventHandlingComponent delegate)

Constructs the component with given delegate to receive calls.

Parameters:

delegate - The instance to delegate calls to.

Method Details

handle

@Nonnull
public MessageStream.Empty<Message> handle(@Nonnull
 EventMessage event,
 @Nonnull
 ProcessingContext context)

Description copied from interface: EventHandler

Handles the given event within the given context.

The result of handling is an empty stream.

Specified by:

handle in interface EventHandler

Overrides:

handle in class DelegatingEventHandlingComponent

Parameters:

event - The event to handle.

context - The context to the given event is handled in.

Returns:

An empty stream containing nothing.