We earlier saw that message bus
applications interact with each other with the help of request-response queues. If
you have ever worked in any messaging solution (like JMS) before, then you will
appreciate the fact that queues are addressed by themselves, which will not give you
any further information about the underlying service. Information on the operations
available, or the messaging patterns to expect, or the schema for the types exchanged
is never available at the queue-level. In other words, services are not described in a
message bus.
What is available is just the messaging counterparts for the put and get primitives so
that messages can be sent to and received from the message bus. So consumer or client
applications should have pre-awareness of the format of the messages exchanged.
This implies everything has to be known before hand??”rather, static binding or
compile-time binding becomes the norm.
Chapter 1
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Let us now consider the service bus. We said earlier that many ESB solutions are
based on WSDL technologies, and they use XML formats for message translation
and transformation.
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