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

by Hohpe Gregor

These two simple classes sending simple messages illustrate a number of the patterns: • Message Channel (60) and Point-to-Point Channel (103)—One channel for transmitting the requests, another for transmitting the replies. • Document Message (147)—The default type of message, used as both the request and the reply. • Request-Reply (154)—A pair of messages sent over a pair of channels, allowing the two applications to have a two-way conversation. • Return Address (159)—The channel to send the response on. • Correlation Identifier (163)—The ID of the request that caused this response. • Datatype Channel (111)—All of the messages on each channel should be of the same type. • Invalid Message Channel (115)—What happens to messages that aren’t of the right type. The example code also demonstrates a couple of patterns from Chapter 10, “Messaging Endpoints”: • Polling Consumer (494)—How the requestor consumes reply messages. • Event-Driven Consumer (498)—How the replier consumes request messages.