Why use a rules engine?

If you are not familiar with rules engines, you may be wondering why you would want to use one. In most applications, complex rule processing often takes the form of nested if-else blocks of code which can be very difficult to decipher and to maintain. If rules change, a developer must work with a business user to define the new rules. The developer must then read through the existing logic to understand what is happening and make the necessary modifications. The changes must then be recompiled, tested, and redeployed. A rules engine provides a means to separate the rules or logic of an application from the remaining code. Separating these rules provides several distinct advantages.

• A rule engine allows for a more declarative style of programming where the rules define what is happening, without describing how it is happening. This makes it much easier to read than nested 'if-else' blocks of code. It's also easier to make changes without introducing bugs in your code.

• The rules are written in a language that is easier for non-developers to understand. This makes it easier for business users to validate and even modify the rules without having to involve developers.
  

• A rule engine allows for changes to be made to the rules without requiring that you recompile your application. If your code must pass through a strict deployment workflow, this can be a huge time saver and can also save a significant amount of money.

After all this, you may be interested in using Liferay's rules engine, so let's get started with it.