//tag::ref-doc[] = Aggregator Processor Aggregator processor enables an application to aggregates incoming messages into groups and release them into an output destination. `java -jar aggregator-processor-kafka-<version>.jar --aggregator.message-store-type=jdbc` Change kafka to rabbit if you want to run it against RabbitMQ. == Payload If an input payload is a `byte[]` and content-type header is a JSON, then `JsonBytesToMap` function tries to deserialize this payload to a `Map` for better data representation on the output of the aggregator function. Also, such a `Map` data representation makes it easy to access to the payload content from SpEL expressions mentioned below. Otherwise(including a deserialization error), the input payload is left as is - and it is the target application configuration to convert it into a desired form. == Options //tag::configuration-properties[link-to-catalog=true] https://github.com/spring-cloud/spring-functions-catalog/tree/main/function/spring-aggregator-function#configuration-options[See Spring Functions Catalog for configuration options]. //end::configuration-properties[] //end::ref-doc[]