4005ff874d
Add support for `FunctionExpression` and apply it alongside with `expression`, where it is possible
For example:
```
.enrich(e -> e.requestChannel("enrichChannel")
.requestPayload(Message::getPayload)
.shouldClonePayload(false)
.<Map<String, String>>headerFunction("foo", m -> m.getPayload().get("name")))
```
Remove redundant functional interfaces in favor of `Function`
FunctionExpression: Add JDBC Splitter sample
Minor Polishing to FunctionExpression
FunctionExpression: JavaDocs
Spring Integration Java DSL
See the Spring Integration Java DSL Reference for more info.