Custom constraints vs custom validator implementations

behrangsa · **Posted:** Tue Mar 03, 2015 4:49 am

Hi,

Are there scenarios in which it is recommended to implement a custom javax.validation.Validator rather than implementing custom constraints and annotating classes with them?

To be more precise, let's pretend we have a model (entity, DTO, etc.) that has a complex validation logic. Are there scenarios in which it is advised that rather than annotating our DTO with a custom constraint annotation such as given in the following listing:

Code:

@ComplexConstraint
public class MyComplexDto {
}

one should instead implement a custom Validator:

Code:

Validator validator = new MyCustomValidator(); // this can be obtained via injection, etc.
validator.validate(myComplexDto);

I always assumed that Validator is primarily meant to be implemented by implementations of the JSR 303 spec, rather than end users on a case by case basis.

What do you think?

Thanks in advance,
Behrang

emmanuel · **Posted:** Tue Mar 03, 2015 9:21 am

Nan, you can manually validate things if you want but I would not implement java.validation.Validator as a user.