A business rule engine applied to e-government services integration 16 1

There is a lot of discussion concerning to the nature of a process and of a rule. In part, this is due to the division of the market around rules driven by BPM applications (Business Process Management) and pure rules engines. One way to look at it is that it potentially removes all the decision diamonds of the process' flows and replaces them with declarative, sharable business

separating data and process was that data definitions changed more slowly than processes, and that the same argument can be applied for processes and rules, making another interesting observation. Thus, the idea is that the business processes are relatively static and only the rules are dynamic. Sinur's studyI5 showed that, in practice, close to 65% of business rules were actually relatively static, while 35% were very volatile. Of these volatile rules, only half were typically satisfactory to be updated directly by the business users.

####### 2 Business Rules Standards and Tools

A lot of research and standardization in Business Rules are being developed. OMG is specifying the Business Semantics of Business Rules (BSBR)""~. BRG created the BR ~ a n i f e s t o " and W3C is specifying the Semantic Web Rule Language (SWRL) 1 8. Figure 1 display the evolution of standards that can be used to represent business rules or that are converging to represent them.

Figure I. XML Standards towards Business Rules

Aqueo Kamada, Manuel Mendes

2.4 The BSBR Meta-model

Due to the lack of a consensus to define business rules, OMG published a request for proposal (RFp)16 requesting proposals to present solutions to allow business people to define the policies and the rules that run their businesses in their own language, in terms of the artifacts with which they accomplish their businesses. Besides that the other objective is to capture those rules in a clear way, not ambiguous and quickly transformable in other representations, such as the representations for the business people, for the software engineers, and for the automated systems of business rules execution. This RFP requested proposals for (i) a MOF metamodel for the specification of business rules for business people; (ii) a metamodel for the capture of vocabularies and definitions of the conditions used in business rules; (iii) an XML representation of business rules and vocabularies based on XMI in order to allow rules and vocabulary interoperability among software tools that manage business rules. The resulting BSBR Metamodel is intended not for business people but for software engineers that build tools for business people. In this paper, the following convention is used, adapted from BSBR", for the representation of facts and business rules:

underlined bold - community vocabularv terms Following there are some examples of structural and operative business rules defined according to this metamodel. structural business rule: A rental always has exactly one return branch. operative business rule: Each driver of a rental must be a qualified driver.

2.4 Business Rules Tools

The main commercial tools for business rules execution are Blaze

Corticon Decision ~ a n a ~ e m e n t ~ and The main open source business rules engines are OFBiz Rule ~ n ~ i n e ~ ~ , a n d a r a x ~ ~ ,~ r o o l s ~ ~and Jena 227.

This section presents an e-Government scenario to exercise the execution of business rules. This scenario is inserted in the context of a Brazilian e- Government applications environment, in the SBo Paulo state9. To simplify,

164 Aqueo Kamada, Manuel Mendes

The citizen lost hislher Id Card and the citizen registered a @ and the Id Card is registered

and the Id Card is pre-registered

the following facts is true: The citizen lost hislher Id Card The citizen has hislher Id Card stolen

(ReceiveBO).

electronically (Retrieve-Id-Card-Data).

BO Data (PreRegister-Id-Card) only if the Id Card is not registered.

different from Id Card Data must have this information (differences) logged (Log-CancellationService-Resulo.

(Log-CancellationService-Result).

The rule set for requesting an Id Card Replacement Issue service is: Rule Set 5- Rules to request Id Card Replacement

(Request-Idcard-Replacement) only if at least one of the following facts is true: The Citizen lost hisher Id Card and the Citizen registered a BO and the Id Card has been cancelled The Citizen wants to change hislher photograph The Citizen wants to change hidher name The Citizen wants to change hislher signature

Imagine a Web Portal that is based on life events that begins to treat the

short sentence indicating what happened to you or what do you want to do."

A business rule engine applied to e-government services integration 165

Assuming that the citizen enters: "I lost my identification card", the

with the provided Id Card number and a few interactions the system discovers that the citizen's desire and reason can be resumed to "the request for a new issue of an identification card, due to the loss of the citizen's Id card". Although the strategies to discover user's desire are very interesting, they are outside the scope of this article.

After the citizen's desires have been discovered the Business Rule Engine (BRE) generates the fact "citizen lost Id Card" in the Repository. The BRE begins its job by searching for facts and business rules. It discovers that the main rule (Rule 5) related to the citizen's desire is included in the rule set "Rules to request Id Card Replacement". As it can be seen in this main rule, the dispatching of the action (Request-Idcard-Replacemenq has as pre-condition the facts "Citizen lost

simplify, it is assumed that the Citizen does not want to change anything, although helshe could change the photograph, name and signature. All the facts and business rules that have direct or indirect relationship with the reason "loss of the identification card" must be considered, which means all the facts and rule sets listed in the subsection 3.

This section intends to show how actions should be dispatched when a business rule is in execution. In general these actions are implemented as Web services and/or components wrapping accesses to legacy applications. When searching the BVRR, the BRE discovers that it is necessary to

and "The Id Card is cancelled". Based on the Rule 2, an action (BO-Register) should be dispatched, since the condition "The citizen lost hisher Id Card" was satisfied. Assuming that the citizen accepted and supplied the necessary data to register a BO, the BO data begins to exist electronically and the fact "The

####### citizen registered a " is generated.

As it can be seen in Rule 1, to cancel an Id Card it is necessary to have one of the conditions "The Id Card is registered" or "The Id Card is