Chapter 5. Consuming the events
What information consumes is rather obvious: it consumes the attention of its recipients. Hence, a wealth of information creates a poverty of attention and a need to allocate that attention efficiently among the overabundance of information sources that might consume it.
Herbert Simon
We now move on to the event consumer. This is the mirror image of the event producer that we discussed in chapter 4, so we recommend that you read that chapter before reading this one. In this chapter we look at
- The notion of an event consumer, its role, and the definition element that describes it
- The different types of event consumers
- The different types of interaction with an event consumer
- The distinction between an event consumer and a subscriber
We also include a specification of the event consumers used in the Fast Flower Delivery application. We start by defining the event consumer, the core concept of this chapter.
The event consumer is the logical complement of the event producer. An event consumer accepts event objects from entities in an event processing network and processes them. How it actually processes the event objects lies outside the scope of the EPN model.
We represent an event consumer as an event processing network node that has only input terminals, as you can see in figure 5.1.
