Introduce an API extension for WADL which would live here:
https://github.com/jboss-switchyard/core/tree/master/extensions

A WADLService interface would then parse and map a WADL definition to our service metadata abstraction, e.g.
https://github.com/jboss-switchyard/core/blob/master/extensions/java/src/main/java/org/switchyard/extensions/java/JavaService.java

We will also need to update the deployer to recognize a WADL interface type and pull in the correct interface parser:
https://github.com/jboss-switchyard/core/blob/master/deploy/base/src/main/java/org/switchyard/deploy/internal/Deployment.java#L403