Chapter 4. Improving Our Rule Syntax

In the previous chapters, we've seen how to configure our environment in order to run our first Drools-based rules, written in the DRL language. We've played with the basic structure of rules and how to configure an environment for them to run, however, we've barely seen the surface of the Drools rule language (DRL) capacity. Like an iceberg, there's much more to it than what you see at first.

In this chapter, we'll discuss the DRL language, its syntax and possibilities, and examples from our eShop case in detail. We will cover the following topics:

• Discussing the different ways in which the rules can read and modify the data, along with their understanding of the world
• Configuring the rules using attributes, global variables, and many other features required to use the rules to its full potential
• Discussing how the execution of Drools rules can be controlled by many different mechanisms