Rule engine design pattern  #1219

Description:
The Rules design pattern is a behavioral design pattern that enables the encapsulation of business rules into isolated, reusable units. This pattern allows for the dynamic application of business logic at runtime and promotes the separation of concerns, making the system more modular and easier to maintain.

Main Elements of the Pattern:

1. Rule Interface: Defines the contract for all rules, typically including a method to evaluate the rule and another to execute the rule's action.
2. Concrete Rules: Implementations of the Rule interface, each encapsulating a specific piece of business logic.
3. Rule Engine: Responsible for managing and executing rules. It evaluates which rules should be applied based on the given context and executes them accordingly.
4. Context: The data or state that the rules operate on. This is passed to the rule engine and rules during execution.

References:

• Rules Design Pattern by Michael Whelan
• Project Contribution Guidelines

Acceptance Criteria:

1. Create a Rule interface with methods to evaluate and execute a rule.
2. Implement at least three concrete rule classes demonstrating different business logic scenarios.
3. Develop a RuleEngine class capable of evaluating and executing a set of rules against a provided context.
4. Include unit tests for the RuleEngine and the concrete rule classes to ensure correctness and robustness.