Motivation

The reasons for creating this library are:

• A simple structure for creating validations that throw an exception.
• An easy-to-use DSL that guides the user in how to use the library.
• Avoiding combing lots of validation logic in one guard clause.
• Avoid using reflection style annotations for this, less magic
• Easy to debug
• Easy to read code when implementing multiple validation rules on one input, instead of lots of complex logic in an 'if' statement.
• Use of Java 8+ predicates to create validation rules. This allows rules to be combined using a predicate interface using logical operands (and, or and not).
• Several ways of return exceptions, either throw an exception on first validation failed, or throw all exceptions under a wrapper exception when multiple validation rules fail (notification patterns).
• Can build a set of rules (predicates) and share within the codebase, or as an accompanying library to Valid8or.

This is not for simple validations, where a simple guard clause (if statement throwing an exception) would be needed due to its simplicity.