Support for null payloads. [INT-997]

Oyvind Kvien opened INT-997 and commented

Spring Integration should support null payloads.

A common case is when using legacy services in a service-activator. The service might return null, and I don't want to refactor it as it's been running stable for years. If Spring Integration don't support null payloads I'll be forced the create a wrapper around it to control it's return type, which is poor design.

Another common case is when using an XmlPayloadUnmarshallingTransformer, like this:
<si-xml:unmarshalling-transformer input-channel="freeTextSearchResponseChannel" unmarshaller="freeTextSearchUnmarshaller"/>

It receives XML from channel "freeTextSearchResponseChannel" and unmarshals it. If the XML is invalid the transformer will return null based on which unmarsller you pick. This will cause the message payload to be null.

Affects: 1.0.3

Reference URL: http://forum.springsource.org/showthread.php?t=85345

Issue Links:

• #6203 Add support for null return values in gateway/service-activator methods

8 votes, 7 watchers

Start by reviewing the service-activator and XmlPayloadUnmarshallingTransformer entry points described in the issue, along with the related gateway/service-activator issue #6203. Define how null returns and invalid XML results should be represented, then verify that legacy service returns and transformer results can be handled without requiring a wrapper.