Package org.axonframework.messaging.deadletter

Interface DeadLetter<M extends Message>

Type Parameters:

M - The type of Message represented by this interface.

All Known Implementing Classes:

GenericDeadLetter, JdbcDeadLetter, JpaDeadLetter

public interface DeadLetter<M extends Message>

Interface describing a dead lettered Message implementation of generic type M.

The time of storing the message() is kept through enqueuedAt(). The last time this letter was accessed on either

invalid reference

SequencedDeadLetterQueue#requeue(DeadLetter, UnaryOperator)

or

invalid reference

processing

, is kept in lastTouched(). Additional information on why the letter is enqueued can be found in the diagnostics.

Since:

4.6.0

Author:

Steven van Beelen, Allard Buijze

Field Summary

Fields

Modifier and Type	Field	Description
static final Context.ResourceKey<DeadLetter<?>>	RESOURCE_KEY	The Context.ResourceKey used whenever a Context would contain a DeadLetter.

Method Summary

Modifier and Type	Method	Description
Optional<Cause>	cause()	The cause for the message() to be dead lettered.
default Context	context()	Returns the Context associated with this dead letter, carrying resources that were present in the ProcessingContext when the letter was enqueued.
Metadata	diagnostics()	The diagnostic Metadata concerning this letter.
Instant	enqueuedAt()	The moment in time when the message() was entered in a dead letter queue.
static Optional<DeadLetter<?>>	fromContext(Context context)	Returns an Optional of {DeadLetter}, returning the resource keyed under the RESOURCE_KEY in the given context.
Instant	lastTouched()	The moment in time when this letter was last touched.
DeadLetter<M>	markTouched()	Construct a copy of this DeadLetter, replacing the lastTouched() with the current time.
M	message()	The Message of type M contained in this letter.
DeadLetter<M>	withCause(Throwable requeueCause)	Construct a copy of this DeadLetter, replacing the cause() with the given requeueCause.
default DeadLetter<M>	withDiagnostics(UnaryOperator<Metadata> diagnosticsBuilder)	Construct a copy of this DeadLetter, replacing the diagnostics() with the result of the given diagnosticsBuilder.
DeadLetter<M>	withDiagnostics(Metadata diagnostics)	Construct a copy of this DeadLetter, replacing the diagnostics() with the given diagnostics.

Field Details

RESOURCE_KEY

static final Context.ResourceKey<DeadLetter<?>> RESOURCE_KEY

The Context.ResourceKey used whenever a Context would contain a DeadLetter.

Method Details

fromContext

static Optional<DeadLetter<?>> fromContext(Context context)

Returns an Optional of {DeadLetter}, returning the resource keyed under the RESOURCE_KEY in the given context.

Parameters:

context - the Context to retrieve the DeadLetter from, if present

Returns:

an Optional of {DeadLetter}, returning the resource keyed under the RESOURCE_KEY in the given context

message

M message()

The Message of type M contained in this letter.

Returns:

The Message of type M contained in this letter.

cause

Optional<Cause> cause()

The cause for the message() to be dead lettered. Can be an Optional.empty() in case this letter is enqueued without a causal error. For instance, when another letter already present in the queue was blocking it being handled.

Returns:

The cause for the message() to be dead lettered.

enqueuedAt

Instant enqueuedAt()

The moment in time when the message() was entered in a dead letter queue.

Returns:

The moment in time when the message() was entered in a dead letter queue.

lastTouched

Instant lastTouched()

The moment in time when this letter was last touched. Will equal the enqueuedAt() value if this letter is enqueued for the first time.

Returns:

The moment in time when this letter was last touched.

diagnostics

Metadata diagnostics()

The diagnostic Metadata concerning this letter.

Returns:

The diagnostic Metadata concerning this letter.

markTouched

DeadLetter<M> markTouched()

Construct a copy of this DeadLetter, replacing the lastTouched() with the current time.

Returns:

A copy of this DeadLetter with lastTouched() set to now.

withCause

DeadLetter<M> withCause(Throwable requeueCause)

Construct a copy of this DeadLetter, replacing the cause() with the given requeueCause.

Parameters:

requeueCause - The new cause of the DeadLetter under construction.

Returns:

A copy of this DeadLetter, replacing the cause() with the given requeueCause.

withDiagnostics

DeadLetter<M> withDiagnostics(Metadata diagnostics)

Construct a copy of this DeadLetter, replacing the diagnostics() with the given diagnostics.

Parameters:

diagnostics - The diagnostic Metadata to append to the DeadLetter under construction.

Returns:

A copy of this DeadLetter, replacing the diagnostics() with the given diagnostics.

withDiagnostics

default DeadLetter<M> withDiagnostics(UnaryOperator<Metadata> diagnosticsBuilder)

Construct a copy of this DeadLetter, replacing the diagnostics() with the result of the given diagnosticsBuilder. The diagnosticsBuilder will be invoked with the diagnostics of this instance.

Parameters:

diagnosticsBuilder - The lambda constructing diagnostic Metadata to replace the Metadata of the DeadLetter under construction.

Returns:

A copy of this DeadLetter, replacing the diagnostics() with the result of the given diagnosticsBuilder.

context

default Context context()

Returns the Context associated with this dead letter, carrying resources that were present in the ProcessingContext when the letter was enqueued. Defaults to Context.empty() if not overridden.

The following resources are stored and restored through this context:

• TrackingToken.RESOURCE_KEY — always present when the letter was enqueued by a streaming event processor.
• LegacyResources.AGGREGATE_TYPE_KEY, LegacyResources.AGGREGATE_IDENTIFIER_KEY, and LegacyResources.AGGREGATE_SEQUENCE_NUMBER_KEY — present only when the event was stored by an aggregate-based event storage engine.

Returns:

The Context associated with this dead letter.