Chapter 6. The event processing network
If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them.
Henry David Thoreau
The event processing network is the central concept in this book, and we start this chapter with a summary of the concept and the notation that we introduced in chapter 2 and then take a more detailed look. The EPN links two fundamental building blocks, the event producers of chapter 4 and the event consumers of chapter 5. It provides a way of modeling the processing that takes place between these producers and consumers. This intermediate processing is represented by three additional building blocks: event processing agents (EPAs), global state elements, and channels.
In this chapter we look at the EPN and these three building blocks. In particular we discuss the following:
- The event processing network itself. We start with a summary of the concept and the notation that we introduced in chapter 2 and then look at further details.
- The concept and anatomy of EPAs, and a discussion of the different types of EPAs. We explore these types in more depth in chapters 8 and 9.
- The concept and functions of an event channel.
- The way that we represent global state in an event processing network.