Rule Engines
Description of rule engines
The rule engine is a tool which allows reproducing logical rules. This engine controls the evaluation of the rules by means of RuleSet, a data file, which declares the rules in a form that is readable by human. User does not have to take care of the rules order and of the rules dependence; this is overtaken by the rules engine.
Function of rule engines
The rules will be read from the RuleSet and according to the data, without demanding chronological order, transferred and evaluated by engine. According to the different optimizing algorithms only those rules will be fired by engine, which are dependant on the facts and its results. The rules will be repetitively evaluated as soon as a rule will be broken or when from the result of previous rules new facts accrue.
Usage of rule engines
Rule engines will be used there, where many rules (Business rules) has to be processed and frequent customization is necessary. For example by software based configuration of a car there are many rules, resulting to the choice which depends on the user.
Advantage of rule engines
A big advantage is that rules are transferred into an external file (RuleSet) and are readable by human. They can be stored as RuleSet, independently from their order, compared to procedural programming, where the order of a logical rule has a high priority. By customizing, the rules have to be implemented in the source code exactly in the order as they are expected.
Values of rule engines
- Less customizing complexity through rules support in a form of a readable file.
- The rules do not have to be maintained by a programmer.
- The order during the RuleSet maintenance is not important.
- Less bugs during maintenance of the quell code.
