Architects should not undervalue the importance of the messaging layer, since it can limit the extensibility and flexibility of the EAI solution. For example, it s going to be difficult to adapt a proprietary messaging layer to other messaging systems that may appear over the years in an enterprise. The notion of adapters for message brokers has been considered for years. However, as with so many other things, each message broker vendor has had its own concept of exactly what an adapter should be. To date, there is no standard.
Adapters are a layer between the message broker and the source or target application or data.
Thin adapters are offered by the most popular message brokers today. In most cases, they are simple API wrappers, or binders, delivered as a set of libraries, that map the interface of the source or target system to a common interface supported by the message broker. In other words, they simply perform an API binding trick, binding one API to another. Thin adapters have the advantage of simplicity in implementation. They have a number of disadvantages, though.