1 of 22

Business Rules with JBoss Drools

Jeff davis

Linked-in

Google +

2 of 22

Agenda

Introduction to Business Rules

What are Business Rules?
What is a Business Rule Management System (BRMS)
Benefits to a BRMS

Understanding a Rules Engine

Facts, Rule Bases and Repository
Syntax of a Business Rule

Using a BRMS at Your Enterprise

Use Cases & Benefits

Selecting a Rules Engine
Roadmap/Next Steps

3 of 22

What is a Business Rule?

“A statement that defines or constrains some aspect of the business which is intended to assert business structure or to control or influence the behavior or the business” (Business Rules Group)

“Business rules or business rulesets describe the operations, definitions and constraints that apply to an organization in achieving its goals.” (Wikipedia)

“A formal and implementable expression of some user requirement”

“The practices, processes, and policies by which an organization conducts its business”

Definitions and Inferences
Computations
Constraints
Instructions
Presentation
Process

Types of Rules

4 of 22

What is a Business Rules Engine?

Rule Builder/Editor

(Tools for developing and debugging rules)

Rule Deployment and Configuration (Tools for deploying and managing rules)

Rules Engine

Business

System

Business

System

Business

System

Shared�Rules

Repository

5 of 22

Traditional Approach to Business Rules

The traditional (ad hoc) approach of dealing with rule changes leads to…

Reduced organizational agility
Reduced employee productivity
Increased load on IT

Issues

Rules are hidden in code or isolated within the organization
Changes are hard to track and maintain over time
Rules used by systems have to be programmed and require IT resources
Duplication and multiple versions of the same rules
Lack of auditability, traceability
Decision changes cannot be easily tested or simulated

Where Business Rules Typically Exist

Applications

Processes

People

Documents

A Business Rules Management Systems (BRMS) is an integrated application development and execution platforms, allowing organizations to define, deploy, monitor and maintain the variety and complexity of decision logic that is used by operational systems. A BRMS allows decision logic to be extracted and managed separately from core application code, so that it can be easily understood, maintained and re-used across the organization.

A BRMS includes, at a minimum, three primary components:

A repository allowing rules to be externalized from core application code – the repository allows decision logic to be managed as an enterprise asset, making it easier to understand and update, along with consolidating it from disparate applications and information silos so that this logic can shared and re-used across the organization.
Tools allowing both technical and non-technical users to define and manage decision logic that was previously buried in code. These tools give business functions the ability to define application behavior, while also providing the ability for business and IT to work collaboratively on application development and maintenance.
A runtime engine allowing production systems to access and execute decision logic managed within the BRMS – the “rule engine” allows combinations of inter-related rules to be executed based on specific business context, using a combination of data inputs, sets of applicable rules, and execution algorithms that define how to process the data and rules in order to provide an output.

By adopting the BRMS approach, organizations are able to effectively deal with the problems associated with traditional embedded decision logic. The organization gains visibility and access to business rules, along with the ability to more easily define and automate them for use in their operational systems. In addition, business experts can now actively participate in the definition and management decision logic, reducing the amount of time and effort required to update decision logic in production systems, and increasing the organization’s ability to respond to changes in the business environment. Also, organizations now have the ability to implement very fine-grained and precise decision logic within their systems to a degree they have not been able to do previously with traditional coding practices.

6 of 22

Moving to a BRMS

Where Business Rules Typically Exist

Applications

Processes

People

Documents

Business Rule Management System

Rules are Defined, Analyzed and Maintained

User Tools

Rules are Stored and Shared

Rule Repository

Rules are Deployed, Executed and Monitored

Rule Server

Eliminate decision silos
Make decision logic accessible to Business and IT
Implement fine-grained, context-specific logic

A Business Rules Management Systems (BRMS) is an integrated application development and execution platforms, allowing organizations to define, deploy, monitor and maintain the variety and complexity of decision logic that is used by operational systems. A BRMS allows decision logic to be extracted and managed separately from core application code, so that it can be easily understood, maintained and re-used across the organization.

A BRMS includes, at a minimum, three primary components:

A repository allowing rules to be externalized from core application code – the repository allows decision logic to be managed as an enterprise asset, making it easier to understand and update, along with consolidating it from disparate applications and information silos so that this logic can shared and re-used across the organization.
Tools allowing both technical and non-technical users to define and manage decision logic that was previously buried in code. These tools give business functions the ability to define application behavior, while also providing the ability for business and IT to work collaboratively on application development and maintenance.
A runtime engine allowing production systems to access and execute decision logic managed within the BRMS – the “rule engine” allows combinations of inter-related rules to be executed based on specific business context, using a combination of data inputs, sets of applicable rules, and execution algorithms that define how to process the data and rules in order to provide an output.

By adopting the BRMS approach, organizations are able to effectively deal with the problems associated with traditional embedded decision logic. The organization gains visibility and access to business rules, along with the ability to more easily define and automate them for use in their operational systems. In addition, business experts can now actively participate in the definition and management decision logic, reducing the amount of time and effort required to update decision logic in production systems, and increasing the organization’s ability to respond to changes in the business environment. Also, organizations now have the ability to implement very fine-grained and precise decision logic within their systems to a degree they have not been able to do previously with traditional coding practices.

7 of 22

Benefits of the Business Rule Approach

Reduce time and resources required to deploy changes
Author and maintain rules using non-technical language
Express decision logic with increased precision
Make decisions based on specific context
Increase decision automation
Improve visibility and understanding of how decisions control systems

Lower maintenance costs; respond quickly to change
Business experts can manage and validate decision logic
Increase profitability of product, pricing and promotional offerings
Customize decisions when possible, standardize if needed
Improve process efficiency
Ensure compliance; enable sharing/re-use of decision logic

What does it enable?

What is the value?

BRMS

Now that you have an understanding of a Business Rule Management System is, let’s spend some time looking at the key benefits that result from the use of a BRMS:

Reduces the time and resources required to change decision logic -- a BRMS increases the ability to respond to ongoing change, while simultaneously decreasing application development and maintenance costs. “Forrester has identified business rules as a key enabling technology…facilitates fast changes to business logic in response to changing business requirements.” (Forrester Research, Trends: Business Rules Platforms, 2008)

[click]

By allowing business functions to be involved in the definition and ongoing maintenance of business rules a significant load is shifted away from IT, while allowing IT to focus on the maintenance and management of the overall systems. This creates a win-win situation for organizations using a BRMS.

[click]

Provides the ability to express decision logic with increased precision – this allows decision variability to be easily handled, and enables fine-grained decision logic to be implemented…a BRMS improves product and pricing decisions, customer service recommendations and even fraud detection

[click]

Enables decisions to be made based on specific, situational context – a BRMS allows decisions to be made based on inputs from multiple sources and to use the context of each individual order, customer, transaction or process in processing the relevant and applicable rules. This in turn allows for highly customized decisions if the situation allows, while also enforcing standardization if required (such as meeting a regulatory mandate).

[click]

- Improves the efficiency of processes through decision automation – a BRMS provides the ability to automate many decisions that have typically been handled manually (by people), even complex decisions based on a number of factors or conditions. “Enterprises need not only decisions, but also automated decisions that enable them to define why, when and how decisions should be made. The proliferation of business options, products, services…threatens to overwhelm enterprises…” (Gartner, Intelligent Decision Mgmt with Business Rules)

[click]

Improves visibility and understanding of where decision logic is used and how it drives operational systems – business rules are easily accessible, allowing them to implemented and re-used across disparate systems. This also allows organizations to ensures accuracy, consistency and enforcement of policies.

8 of 22

Syntax of a Business Rule

Declarative
Expressed in Natural Language
Follow an If-Then Syntax
Atomic – a Single Rule is Either True or False
Examples:

If an insurance claim exceeds $1200, require a review by an manager.
If a vacation request exceeds amount of available hours, reject.
If an order exceeds $75, provide free shipping.
If customer is new, send out welcome email message with discount coupons.

9 of 22

Rule Engine Basics

Rule-Based Systems consist of a rule base, a set of facts, and an inference engine.

Set of Facts (Working Memory /DB)

THEN [Claim] is Approved

IF [Diagnosis] is Covered && [Claim.Cost] < $250

THEN [Claim] is Approved

IF [Customer] is Preferred && [Order.Cost] < $250

THEN [Order] is Approved

Rule-Base

Acme places Order 101 for $175

Acme is a preferred Customer

Inference

Engine

Acme Order 101 is Approved

Result:

10 of 22

Types of Facts

There two general types of facts:

Volatile – Represent the instance data that will trigger the rules engine to fire. For example, data submitted for validation during an ESP claim process.
Non-Volatile – Generally historically or rather static data. For example, vendor and contract related data.

In most cases, a database will likely be the source for the non-volatile facts, whereas a transaction application will be providing the volatile data that requires processing.

11 of 22

Relationship between Services

This illustration depicts the relationship between the rules engine, exposed as a “decision service”, and the BRMS.

The BRMS is the interface by which the rules can be managed and maintained.

12 of 22

Use Cases for Rules Engine

Most likely, you work in rules-based enterprise. Examples:

Determine whether a claim is covered by the terms of a contract.
Determine the sequence of steps required for processing a new order.
Determine the invoice amounts payable to vendors.
Determine who a customer service case is assigned.
Determine what background checks are required for an applicant.
Determine which contracts or services are available for sale.

The list likely goes on –numbering in the thousands…

13 of 22

Business Rules & Your Enterprise

Where do these business rules reside today for your Enterprise?

Backoffice systems such as an order entry system. Many likely reside in database stored procedures.
Business applications such as e-commerce web sites.
Likely a multitude of other locations.

The implication of this?

No central repository means limited visibility to what rules are used where.
Viewing and managing the rules can only be done by IT resources.
Changing rules is a costly, time-consuming and error-prone exercise.

14 of 22

Choosing a BRMS

Op

Open Source

*Now Oracle Policy Automation

15 of 22

How do I Choose?

Nearly all of the BRMS’ shown on the previous slide share more similarity than differences. They all use the same Rules algorithm (Rete), and provide some sort of API access via web services.
They all provide a means for cataloging, managing and versioning of rules.
To various degrees, most provide a graphical means for editing rules, and typically support “domain specific language” support (i.e,. more “English-like” vocabularies for writing rules).

16 of 22

JBoss Drools

Drools is the most well-established open source rules engine, and is supported by JBoss/RedHat.
Thousands of enterprises use Drools. It’s proven to scale, and it continues to evolve at a brisk pace.
Drools now is deeply integrated with jBPM, which is JBoss’ Business Process Management system.
Drools also includes support for Complex Event Processing (ESP) via it’s Fusion plugin. ESP allows real-time monitoring of all business events to identify anomalies.

17 of 22

Drools & jBPM

Drools & jBPM are now tightly integrated. The implication of this is that decision points within your business process models can driven by your business rules.

18 of 22

Integrating Drools

Jboss Drools now includes an integration framework using Apache Camel.

Camel is a lightweight Enterprise Service Bus that allows Drools to be exposed as a services API (i.e., “Decision Service”). This makes it easy to call Drools form a variety of clients using nearly any programming language.

19 of 22

BRMS Roadmap for Your Enterprise

Identify Use Case

Select a target application for the first implementation. For example, a new web application.

Harvest Business Rules

Identify all business rules used by the application. If necessary, remove them from PL/SQL code etc.

Populate BRMS

Add the identified rules in the BRMS. Create procedures to populate working memory.

Create Decision Service

Publish the rules as an API using a decision service. Use the rules in the new application.

Rather than attempt to build a comprehensive collection of all business rules, instead build incrementally. This reduces risk

and builds organizational

familiarity.

20 of 22

Dissecting a Drool Business Rule

rule "ZipMissing"

dialect "mvel"

when

$request : ValidateClaimForAuthorization( propertyZipCode == "" )

then

System.out.println("Invalid Request - ZipCode is missing.");

result.setResultCode(102);

result.setResultDesc(Constant.ERROR102);

end

An “object type” restraint.

public class ValidateClaimForAuthorization {

private int vendorSiteId;

private String jobNumber;

private String propertyZipCode;

private int workAsgnGenSeq;

private String operationSource;

public String getPropertyZipCode() {

return propertyZipCode;

}

public void setPropertyZipCode(String propertyZipCode) {

this.propertyZipCode = propertyZipCode;

}

A “field/method type” restraint.

21 of 22

What’s Next

A follow-up presentation will discuss how to configure Drools integration using Apache Camel.

22 of 22

Sources

Wikipedia

http://bs.doag.org/formes/servlet/DocNavi?action=getFile&did=258698&key=

http://www.jboss.com/pdf/JBossBRMSDataSheet.pdf

http://www.nljug.org/pages/events/content/jspring_2006/sessions/00002/slides/