规则引擎与富域模型

Question

I'm looking into NRules.Net to implement my pricing engine. After some testings, I don't really understand the benefits of using a .net rules engine vs using a rich domain model...

• Rules are still plain CS classes (there is nothing dynamic)
• I have to deal with a black-box (the rule engine) which does not allow me to understand what is going on

In the end, why shall I go for a .net rule engine? Is there anything I'm missing?

Thanks Seb

Answer 1

A rules engine allows you to reason about a Rule as a concept of its own and gives you an elaborate language to play with rules.

You can compose rules dynamically, classify and manipulate lists of rules with different priorities, manage conflicting rules, express them with a convenient DSL that business people might understand, create transformations to make an object comply with a rule, etc.

Without an abstraction of what a Rule is, you can't do all this in a conscious, consistent way.

Not all domains need it but if that general concept often comes up in discussions with your domain experts, a rules engine is probably worth having a look at.