Pre-, Post- and Class validation annotations

[stijn-dejongh]

Outline

Implement the ideas from the Eiffel language regarding design by contract in Java.

Implementation Notes

• Ideally, these are specified as annotations pointing to RuleSet objects
• Other than the Eiffel counterpart, these condition statements should be validated on build-time execution, by informing test-cases, rather than crashing the program during runtime processing.
• Will likely require AOP implementation of sorts

Usage Desisderata

@ValidatedBy(aValid(SomeObject.class).must(notBeNull).must(haveNonNullField(SomeObject::name)).iHaveSpoken())
class SomeObject {

    private String name;
    
    @PreCondition(adheresTo=aValid(SomeObject.class).must(haveNonNullField(SomeObject::name)).iHaveSpoken())
    @PostCondition(adheresTo=aValid(SomeObject.class).must(haveNonNullField(SomeObject::name)).iHaveSpoken())
    public Result doSomething(InputClass input) {
    
    }
}