Interface Message<T>
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- 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.
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method 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-specificMessage
implementation, and other classes.default Message<T>
withAck(Supplier<CompletionStage<Void>> ack)
Creates a new instance ofMessage
with the given acknowledgement supplier.default Message<T>
withNack(Function<Throwable,CompletionStage<Void>> nack)
Creates a new instance ofMessage
with the given negative-acknowledgement function.default <P> Message<P>
withPayload(P payload)
Creates a new instance ofMessage
with the specified payload.
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Method Detail
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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.
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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 messagesack()
method is invoked.- Returns:
- A message with the given payload and ack function.
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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 messagesack()
method is invoked.nack
- The negative-ack function, this will be invoked when the returned messagesnack(Throwable)
method is invoked.- Returns:
- A message with the given payload, ack and nack functions.
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withPayload
default <P> Message<P> withPayload(P payload)
Creates a new instance ofMessage
with the specified payload. The ack/nack functions are taken from the currentMessage
.- Type Parameters:
P
- the type of the new payload- Parameters:
payload
- the new payload.- Returns:
- the new instance of
Message
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withAck
default Message<T> withAck(Supplier<CompletionStage<Void>> ack)
Creates a new instance ofMessage
with the given acknowledgement supplier. The payload, and nack function are taken from the currentMessage
.- Parameters:
ack
- the positive-acknowledgement function- Returns:
- the new instance of
Message
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withNack
default Message<T> withNack(Function<Throwable,CompletionStage<Void>> nack)
Creates a new instance ofMessage
with the given negative-acknowledgement function. The payload and acknowledgment are taken from the currentMessage
.- Parameters:
nack
- the negative-acknowledgement function- Returns:
- the new instance of
Message
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getPayload
T getPayload()
- Returns:
- The payload for this message.
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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.
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getAck
default Supplier<CompletionStage<Void>> getAck()
- Returns:
- the supplier used to retrieve the acknowledgement
CompletionStage
.
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getNack
default Function<Throwable,CompletionStage<Void>> getNack()
- Returns:
- the function used to retrieve the negative-acknowledgement asynchronous function.
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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 benull
- Returns:
- a completion stage completed when the message is negative-acknowledgement has completed. If the negative acknowledgement fails, the completion stage propagates the failure.
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unwrap
default <C> C unwrap(Class<C> unwrapType)
Returns an object of the specified type to allow access to the connector-specificMessage
implementation, and other classes. For example, a Kafka connector could implement this method to allow unwrapping to a specific Kafka message implementation, or toConsumerRecord
andProducerRecord
. If theMessage
implementation does not support the target class, anIllegalArgumentException
should be raised. The default implementation tries to cast the currentMessage
instance to the target class. When a connector provides its ownMessage
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 benull
- Returns:
- an instance of the specified class
- Throws:
IllegalArgumentException
- if the currentMessage
instance does not support the call
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