Interface DeadLetterMessage<T>

Type Parameters:

T - payload type

All Superinterfaces:

Message<T>

public interface DeadLetterMessage<T>
extends Message<T>

Immutable message routed to a logical dead-letter channel.

The failure type and message are local diagnostic data in Message.localMetadata(). Connectors must never map local metadata to a transport. Applications that intentionally publish failure diagnostics must first redact and bound them, then explicitly promote them to portable headers.

Every implementation must provide text values under FAILURE_TYPE_METADATA and FAILURE_MESSAGE_METADATA in its local metadata.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ATTEMPTS_HEADER	Reserved common header containing the total delivery attempts.
static final String	FAILURE_MESSAGE_METADATA	Required reserved local metadata containing the processing failure message.
static final String	FAILURE_TYPE_METADATA	Required reserved local metadata containing the processing failure class.
static final String	SOURCE_CHANNEL_HEADER	Reserved common header containing the source channel.

Method Summary

Modifier and Type	Method	Description
int	attempts()	Total delivery attempts, including the initial delivery.
static <T> DeadLetterMessage<T>	create(Message<T> originalMessage, String sourceChannel, int attempts, RuntimeException failure)	Create a dead-letter message.
default String	failureMessage()	Processing failure message.
default String	failureType()	Processing failure class name.
Message<T>	originalMessage()	Original extendable message envelope.
String	sourceChannel()	Source logical channel.

Methods inherited from interface Message

entity, header, headers, headerValue, localMetadata

Modifier and Type	Method	Description
T	entity()	Payload.
default Optional<String>	header(String name)	Last portable text header value with an exact name.
MessageHeaders	headers()	Ordered portable headers.
default Optional<MessageHeaderValue>	headerValue(String name)	Last portable header value with an exact name.
default MessageMetadata	localMetadata()	Metadata local to this message envelope.

Field Details

SOURCE_CHANNEL_HEADER

static final String SOURCE_CHANNEL_HEADER

Reserved common header containing the source channel.

See Also:

• Constant Field Values

ATTEMPTS_HEADER

static final String ATTEMPTS_HEADER

Reserved common header containing the total delivery attempts.

See Also:

• Constant Field Values

FAILURE_TYPE_METADATA

static final String FAILURE_TYPE_METADATA

Required reserved local metadata containing the processing failure class.

Local metadata is never transported implicitly by a connector.

See Also:

• Constant Field Values

FAILURE_MESSAGE_METADATA

static final String FAILURE_MESSAGE_METADATA

Required reserved local metadata containing the processing failure message.

Local metadata is never transported implicitly by a connector.

See Also:

• Constant Field Values

Method Details

create

static <T> DeadLetterMessage<T> create(Message<T> originalMessage,
 String sourceChannel,
 int attempts,
 RuntimeException failure)

Create a dead-letter message.

Type Parameters:

T - payload type

Parameters:

originalMessage - original message

sourceChannel - source channel

attempts - total delivery attempts

failure - processing failure

Returns:

immutable dead-letter message

Throws:

NullPointerException - if originalMessage, sourceChannel, or failure is null

IllegalArgumentException - if sourceChannel is blank or attempts is less than one

originalMessage

Message<T> originalMessage()

Original extendable message envelope.

Returns:

original message

sourceChannel

String sourceChannel()

Source logical channel.

Returns:

source channel

attempts

int attempts()

Total delivery attempts, including the initial delivery.

Returns:

delivery attempts

failureType

default String failureType()

Processing failure class name.

This local diagnostic is stored under FAILURE_TYPE_METADATA in Message.localMetadata(). It may expose implementation details and must be explicitly sanitized before publication.

Returns:

failure class name

Throws:

IllegalStateException - if the required local metadata is missing or is not a text value

failureMessage

default String failureMessage()

Processing failure message.

This local diagnostic is stored under FAILURE_MESSAGE_METADATA in Message.localMetadata(). It may contain sensitive data and may be arbitrarily long, so it must be explicitly redacted and bounded before publication. A message returned by create(Message, String, int, RuntimeException) stores an empty string when the processing exception has no message.

Returns:

failure message, or an empty string when the processing exception had no message

Throws:

IllegalStateException - if the required local metadata is missing or is not a text value