Book Image

Drools JBoss Rules 5.X Developer's Guide

By : Michal Bali
Book Image

Drools JBoss Rules 5.X Developer's Guide

By: Michal Bali

Overview of this book

<p>Writing business rules has always been a challenging task. Business rules tend to change often leading to a maintenance nightmare. This book shows you various ways to code your business rules using Drools, the open source Business Rules Management System.<br /><br />Drools JBoss Rules 5.X Developer's Guide shows various features of the Drools platform by walking the reader through several real-world examples. Each chapter elaborates on different aspects of the Drools platform. The reader will also learn about the inner workings of Drools and its implementation of the Rete algorithm.<br /><br />The book starts with explaining rule basics, then builds on this information by going through various areas like human readable rules, rules for validation, and stateful rules, using examples from the banking domain. A loan approval process example shows the use of the jBPM module. Parts of a banking fraud detection system are implemented with the Drools Fusion module which is the complex event processing part of Drools. Finally, more technical details are shown detailing the inner workings of Drools, the implementation of the ReteOO algorithm, indexing, node sharing, and partitioning.</p>
Table of Contents (22 chapters)
Drools JBoss Rules 5.X Developer's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Setting Up the Development Environment
Creating Custom Operators
Dependencies of Sample Application
Index

Implementation


In this section we'll define the implementation for various interfaces that we've defined in this chapter. This section is shown for completeness and can be skipped.

First, let's have a look at an implementation of the Message interface. The message is essentially another POJO, so it will basically have getters setters and it will also override the equals, the hashCode, and toString methods.

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
//... other imports
public class DefaultMessage implements Message, Serializable {
  private Message.Type type;
  private String messageKey;
  private List<Object> context;

  public DefaultMessage(Message.Type type, String messageKey,
      List<Object> context) {
    if (type == null || messageKey == null) {
      throw new IllegalArgumentException(
          "Type and messageKey cannot be null");
    }
    this...