org.eclipse.microprofile.reactive.messaging

Interface Message<T>

Type Parameters:

T - The type of the message payload.

public interface Message<T>

A message envelope.

Messaging providers may provide their own sub classes of this type, in order to allow messaging provider specific information to be passed to and from applications.

Method Summary

Modifier and Type	Method and Description
default CompletionStage<Void>	ack() Acknowledge this message.
default Supplier<CompletionStage<Void>>	getAck()
default Function<Throwable,CompletionStage<Void>>	getNack()
T	getPayload()
default CompletionStage<Void>	nack(Throwable reason) Acknowledge negatively this message.
static <T> Message<T>	of(T payload) Create a message with the given payload.
static <T> Message<T>	of(T payload, Supplier<CompletionStage<Void>> ack) Create a message with the given payload and ack function.
static <T> Message<T>	of(T payload, Supplier<CompletionStage<Void>> ack, Function<Throwable,CompletionStage<Void>> nack) Create a message with the given payload, ack and nack functions.
default <C> C	unwrap(Class<C> unwrapType) Returns an object of the specified type to allow access to the connector-specific Message implementation, and other classes.
default Message<T>	withAck(Supplier<CompletionStage<Void>> ack) Creates a new instance of Message with the given acknowledgement supplier.
default Message<T>	withNack(Function<Throwable,CompletionStage<Void>> nack) Creates a new instance of Message with the given negative-acknowledgement function.
default <P> Message<P>	withPayload(P payload) Creates a new instance of Message with the specified payload.

Method Detail

of

static <T> Message<T> of(T payload)

Create a message with the given payload.

Type Parameters:

T - The type of payload

Parameters:

payload - The payload.

Returns:

A message with the given payload, and a no-op ack function.

of

static <T> Message<T> of(T payload,
                         Supplier<CompletionStage<Void>> ack)

Create a message with the given payload and ack function.

Type Parameters:

T - the type of payload

Parameters:

payload - The payload.

ack - The ack function, this will be invoked when the returned messages ack() method is invoked.

Returns:

A message with the given payload and ack function.

of

static <T> Message<T> of(T payload,
                         Supplier<CompletionStage<Void>> ack,
                         Function<Throwable,CompletionStage<Void>> nack)

Create a message with the given payload, ack and nack functions.

Type Parameters:

T - the type of payload

Parameters:

payload - The payload.

ack - The ack function, this will be invoked when the returned messages ack() method is invoked.

nack - The negative-ack function, this will be invoked when the returned messages nack(Throwable) method is invoked.

Returns:

A message with the given payload, ack and nack functions.

withPayload

default <P> Message<P> withPayload(P payload)

Creates a new instance of Message with the specified payload. The ack/nack functions are taken from the current Message.

Type Parameters:

P - the type of the new payload

Parameters:

payload - the new payload.

Returns:

the new instance of Message

withAck

default Message<T> withAck(Supplier<CompletionStage<Void>> ack)

Creates a new instance of Message with the given acknowledgement supplier. The payload, and nack function are taken from the current Message.

Parameters:

ack - the positive-acknowledgement function

Returns:

the new instance of Message

withNack

default Message<T> withNack(Function<Throwable,CompletionStage<Void>> nack)

Creates a new instance of Message with the given negative-acknowledgement function. The payload and acknowledgment are taken from the current Message.

Parameters:

nack - the negative-acknowledgement function

Returns:

the new instance of Message

getPayload

T getPayload()

Returns:

The payload for this message.

ack

default CompletionStage<Void> ack()

Acknowledge this message.

Returns:

a completion stage completed when the message is acknowledged. If the acknowledgement fails, the completion stage propagates the failure.

getAck

default Supplier<CompletionStage<Void>> getAck()

Returns:

the supplier used to retrieve the acknowledgement CompletionStage.

getNack

default Function<Throwable,CompletionStage<Void>> getNack()

Returns:

the function used to retrieve the negative-acknowledgement asynchronous function.

nack

default CompletionStage<Void> nack(Throwable reason)

Acknowledge negatively this message. nack is used to indicate that the processing of a message failed with the reason passed as the parameter.

Parameters:

reason - the reason of the nack, must not be null

Returns:

a completion stage completed when the message is negative-acknowledgement has completed. If the negative acknowledgement fails, the completion stage propagates the failure.

unwrap

default <C> C unwrap(Class<C> unwrapType)

Returns an object of the specified type to allow access to the connector-specific Message implementation, and other classes. For example, a Kafka connector could implement this method to allow unwrapping to a specific Kafka message implementation, or to ConsumerRecord and ProducerRecord. If the Message implementation does not support the target class, an IllegalArgumentException should be raised. The default implementation tries to cast the current Message instance to the target class. When a connector provides its own Message implementation, it should override this method to support specific types.

Type Parameters:

C - the target type

Parameters:

unwrapType - the class of the object to be returned, must not be null

Returns:

an instance of the specified class

Throws:

IllegalArgumentException - if the current Message instance does not support the call