Book Image

Mastering JBoss Drools 6

By : Mariano De Maio, Mauricio Salatino, Esteban Aliverti
Book Image

Mastering JBoss Drools 6

By: Mariano De Maio, Mauricio Salatino, Esteban Aliverti

Overview of this book

Mastering JBoss Drools 6 will provide you with the knowledge to develop applications involving complex scenarios. You will learn how to use KIE modules to create and execute Business Rules, and how the PHREAK algorithm internally works to drive the Rule Engine decisions. This book will also cover the relationship between Drools and jBPM, which allows you to enrich your applications by using Business Processes. You will be briefly introduced to the concept of complex event processing (Drools CEP) where you will learn how to aggregate and correlate your data based on temporal conditions. You will also learn how to define rules using domain-specific languages, such as spreadsheets, database entries, PMML, and more. Towards the end, this book will take you through the integration of Drools with the Spring and Camel frameworks for more complex applications.
Table of Contents (18 chapters)
Mastering JBoss Drools 6
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

The Rule language


Now that we have executed our first rule, it is time to learn a little bit more about the language that we use to define them. In order to do this, we will start by analyzing the rule that we wrote previously and then we will start creating more advanced rules.

All the rules and examples contained in this section can be found in the chapter-02/chapter-02-kjar/ project. We will use this project throughout the rest of the chapter to store different rules.

As it was mentioned in the first chapter, the rule structure is composed of the conditions and consequence, as follows:

rule "name"
when
    (Conditions) - also called Left Hand Side of the Rule (LHS)
then
    (Actions/Consequence) - also called Right Hand Side of the Rule (RHS)
end

The Conditions (LHS) of the rule are written following the DRL language, which for the sake of simplicity, will not be entirely explained in here. We will be looking at the most common usage of the DRL language throughout the book examples. We...