Message Converters
SmallRye Reactive Messaging supports message converters, allowing to transform an incoming message into a version accepted by the method. If the incoming messages or payload does not match the invoked method’s expectation, SmallRye Reactive Messaging looks for a suitable converter. If found, it converts the incoming message with this converter.
Converters can have multiple purposes, but the main use case is about transforming the message’s payload:
To provide a converter, implement a bean exposing the MessageConverter
interface. The canConvert
method is called during the lookup and
verifies if it can handle the conversion. The target
type is the
expected payload type. If the converter returns true
to canConvert
,
SmallRye Reactive Messaging calls the convert
method to proceed to the
conversion.
The previous converter can be used in application like the following, to
convert Message<String>
to Message<Person>
:
Converters work for all supported method signatures. However, the signature must be well-formed to allow the extraction of the expected payload type. Wildcards and raw types do not support conversion. If the expected payload type cannot be extracted, or no converter fits, the message is passed as received.
If multiple suitable converters are present, implementations should
override the getPriority
method returning the priority. The default
priority is 100
. The converter lookup invokes converters with higher
priority (from the least value to the greatest) first.