Liferay Digital Experience Platform provides an implementation of a JSR-94 compliant rules engine as a web app, based on the popular open source Drools project. A rules engine provides a means to separate the rules or logic of an application from the remaining code. This 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 also 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.

This app installs as a Liferay service.