Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions (Addison-Wesley Signature Series (Fowler))

by Hohpe Gregor

There are two common Request-Reply (154) scenarios worth noting; both involve a Command Message (145) request and a corresponding Document Message (147) reply. In the first scenario, Messaging RPC, the requestor not only wants to invoke a function on the replier, but also wants the return value from the function. This is how applications perform an RPC (Remote Procedure Call) using Messaging (53). In the other scenario, Messaging Query, the requestor performs a query; the replier executes the query and returns the results in the reply. This is how applications use messaging to perform a query remotely.