An application needs to invoke functionality provided by other applications. It would typically use Remote Procedure Invocation, but would like to take advantage of the benefits of using Messaging.
How can messaging be used to invoke a procedure in another application?
Use a Command Message to reliably invoke a procedure in another application.
There is no specific message type for commands; a Command Message is simply a regular message that happens to contain a command. In JMS, the command message could be any type of message; examples include an ObjectMessage containing a Serializable command object, a TextMessage containing the command in XML form, etc. In .NET, a command message is a Message with a command stored in it. A Simple Object Access Protocol (SOAP) request is a command message.
... Read the entire pattern in the book Enterprise Integration Patterns
Related patterns:
Remote Procedure Invocation, Message, Message Channel, Messaging, Point-to-Point Channel