A protocol bridge is an integration pattern to connect between two different protocols. For example, HTTP and JMS are two different transport protocols. If there was a way to bridge these two, we could leverage the best of both worlds (open standard nature of HTTP and reliable transport feature of JMS). Typically, it is not straightforward to connect two different protocols and exchange information. We need to connect individual, corresponding channels speaking different protocols in the messaging system. This is demonstrated in the following figure:

A protocol bridge can be viewed as a combination of channel adapters. An adapter can function as a client to the messaging system. With the client role, the adaptor can invoke application functions through the application supplied interfaces. Thus a HTTP channel adapter can be used to access the HTTP service and publish messages on a JMS channel. Similarly, the same adapter can also receive messages from the JMS channel and invoke...