The concept of MRules business rule engine is simple:
- Input Java beans are provided.
- Data is read from these beans and Conditions are evaluated.
- Data is writen into output Java beans.
- An internal caching system allows to avoid several retrievals of the same data from input beans or multiple evaluations of the same condition.
The whole library contains lots of components, which we can classify in different types, depending on their responsability.
- Accessors are responsible of data access (read and write).
- Conditions evaluate data to branch execution.
- Evaluation Operators perform a single data evaluation.
- Logical Operators combine multiple single evaluations.
- Executables (also named “Rules”) are responsible of performing actions and coordinating their execution.
- Actions are special Executable which perform unitary actions (like for instance setting a value).
- The special Executable “Rule Execution Set” is the main root component of a rule set instance.
- Callables are special components which can be invoked any time during execution (for example, functions).
- Builder and Factories read and write rule engine configuration and build rule set instances.
- The contexts allow to launch compilation and execution.
MRules in concieved to be modular and easily extensible. To achive this ambitious goal, an Addon-based structure has been created. Every component of the library is an Addon. It’s so just easy as a pie to add a new feature and to write extensions, which will be dynamically loaded at runtime with very few lines of configuration.
This allows to easily add specific operations in case of a very particular need, although many operations are already possible.