OVal

OVal is a pragmatic and extensible general purpose validation framework for any kind of Java objects (not only JavaBeans) and allows you: * to easily validate objects on demand, * to specify constraints for class fields and getter methods, * to validate objects based on certain EJB3 JPA annotations (namely all field annotations that require a not-null value), * to configure constraints via annotations, POJOs and/or simple XML files, * to express constraints using scripting languages such as Groovy, BeanShell, and JavaScript * to easily create custom constraints, and * to develop new constraint configuration mechanisms When using AspectJ certain programming by contract (aka Design By Contract or DBC) these features are available: * specifying constraints for constructor parameters that are automatically checked when a constructor is called (preconditions), * specifying constraints for method parameters that are automatically checked when a method is called (preconditions), * requiring a certain object state before a method is called (preconditions) * enforcing object validation after an object has been created (invariants), * enforcing object validation before/after a method of an object is/has been called (invariants), * specifying constrains for a method's return value that are automatically checked after a method has been executed (postconditions), * requiring a certain object state after a method is called (postconditions).