metadata for components, processors etc

[Tim Dudgeon]

Is there any mechanism for specifying metadata that describes what 
inputs and outputs components, processors ... can consume/produce.
I'm thinking of this from the perspective of a GUI builder tool that 
allows a route to be assembled so for this it's necessary to know which 
nodes are "compatible" with others. For instance if one produces bananas 
then it can't be directly piped into one that consumes oranges (of 
course TypeConverters need to be considered here).
For instance, is there an existing mechanism for providing @Consumes and 
@Produces annotations on components, processors etc.
Same question for routes, but I suspect that's much the same question.
Tim