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

by Hohpe Gregor

Each filter exposes a very simple interface: It receives messages on the inbound pipe, processes the message, and publishes the results to the outbound pipe. The pipe connects one filter to the next, sending output messages from one filter to the next. Because all components use the same external interface, they can be composed into different solutions by connecting the components to different pipes. We can add new filters, omit existing ones, or rearrange them into a new sequence—all without having to change the filters themselves. The connection between filter and pipe is sometimes called a port. In the basic form, each filter component has one input port and one output port.