Package org.axonframework.messaging.eventhandling.deadletter.jpa

Class EventMessageDeadLetterJpaConverter

java.lang.Object

org.axonframework.messaging.eventhandling.deadletter.jpa.EventMessageDeadLetterJpaConverter

All Implemented Interfaces:

DeadLetterJpaConverter<EventMessage>

public class EventMessageDeadLetterJpaConverter
extends Object
implements DeadLetterJpaConverter<EventMessage>

Converter responsible for converting to and from EventMessage implementations for storage in a SequencedDeadLetterQueue.

Tracking tokens and aggregate data (only if legacy Aggregate approach is used: aggregate identifier, type, sequence number) are stored as Context resources. This converter extracts these resources from the context during serialization and restores them to the context when deserializing.

Since:

4.6.0

Author:

Mitchell Herrijgers

Constructor Summary

Constructors

Constructor	Description
EventMessageDeadLetterJpaConverter()

Method Summary

Modifier and Type	Method	Description
MessageStream.Entry<EventMessage>	convert(DeadLetterEventEntry entry, EventConverter eventConverter, Converter genericConverter)	Converts a DeadLetterEventEntry to a MessageStream.Entry containing the EventMessage implementation and a Context with restored resources.
DeadLetterEventEntry	convert(EventMessage message, @Nullable Context context, EventConverter eventConverter, Converter genericConverter)	Converts an EventMessage implementation and its associated Context to a DeadLetterEventEntry.

Methods inherited from class java.lang.Object

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

Constructor Details

EventMessageDeadLetterJpaConverter

public EventMessageDeadLetterJpaConverter()

Method Details

convert

public DeadLetterEventEntry convert(EventMessage message,
 @Nullable Context context,
 EventConverter eventConverter,
 Converter genericConverter)

Description copied from interface: DeadLetterJpaConverter

Converts an EventMessage implementation and its associated Context to a DeadLetterEventEntry.

The context is used to extract tracking token and domain info (aggregate identifier, type, sequence number) if present. When the context is null, no resources are extracted and corresponding fields in the resulting DeadLetterEventEntry will be null.

In most cases a non-null Context is expected, as the SequencedDeadLetterQueue is typically invoked through Axon's event handling logic, which always provides a context. A null context is only expected when the SequencedDeadLetterQueue is invoked directly by user code outside of the framework's processing pipeline.

Specified by:

convert in interface DeadLetterJpaConverter<EventMessage>

Parameters:

message - The message to convert.

context - The context containing resources such as tracking token and domain info.

eventConverter - The EventConverter for conversion of payload and metadata.

genericConverter - The Converter for conversion of the tracking token, if present.

Returns:

The created DeadLetterEventEntry.

convert

public MessageStream.Entry<EventMessage> convert(DeadLetterEventEntry entry,
 EventConverter eventConverter,
 Converter genericConverter)

Description copied from interface: DeadLetterJpaConverter

Converts a DeadLetterEventEntry to a MessageStream.Entry containing the EventMessage implementation and a Context with restored resources.

The returned entry's context contains the restored tracking token and domain info (aggregate identifier, type, sequence number) if they were stored when the dead letter was enqueued.

Specified by:

convert in interface DeadLetterJpaConverter<EventMessage>

Parameters:

entry - The database entry to convert.

eventConverter - The EventConverter for deserialization of payload and metadata.

genericConverter - The Converter for deserialization of the tracking token, if present.

Returns:

A MessageStream.Entry containing the message and context with restored resources.