What’s special about SwitchYard? It’s SCA.

Service Component Architecture (SCA) is the marriage of these two things. It essentially recognizes that some of your building blocks are going to be local, others are going to be external, all of them need to be as reusable as possible, and their internal/external exposure may change over time. In other words, it's a SOA orchestration of services that is a fluid hybrid between the two worlds. Your code will periodically use a @Service tag to declare a service dependency. And some XML configuration file will help map out the ESB-specifics of (a) exposing necessary services or service compositions to the outside and (b) getting access to outside service dependencies that you'll need.