Spring MVC with hibernate Validator to validate single basic type

Question

Below is the mapped method that I am having trouble with, no matter what value I pass to it the validation returns \"passed validation.\"

@RequestMapping(value          


        

Answer 1

First, as stated by other answers, Hibernate Validator doesn't allow to validate directly primitives like the example in the question. In order to use Hibernate Validator, defining a new class containing a long value is exactly what is required in order to use Hibernate Validator.

Second, and most important, whereas programatic validation is something that works and it is quite simple, it is not clean and maintanable. Let me illustrate this with some examples:

@RequestMapping(value = "testA", method = RequestMethod.POST)
@ResponseBody
public String getTestA(@RequestBody long longValue, BindingResult result) {
   if (longValue > 32) {
     result.rejectValue("longValue", "error.longValue", "longValue max constrained failed");
     return "failed validation for test A";
   } else {
     return "passed validation for test A";
   }
}


@RequestMapping(value = "testB", method = RequestMethod.POST)
@ResponseBody
public String getTestB(@RequestBody long longValue, BindingResult result) {
   if (longValue > 32) {
     result.rejectValue("longValue", "error.longValue", "longValue max constrained failed");
     return "failed validation for test B";
   } else {
     return "passed validation for test B";
   }
}


@RequestMapping(value = "testC", method = RequestMethod.POST)
@ResponseBody
public String getTestC(@RequestBody long longValue, BindingResult result) {
   if (longValue > 32) {
     result.rejectValue("longValue", "error.longValue", "longValue max constrained failed");
     return "failed validation for test C";
   } else {
     return "passed validation for test C";
   }
}

First thing to notice, is withing 3 simple functions, all the validation code is duplicated.

Secondly, if at some point your validations requirements change, and now all the long values must be bigger than 35, you need to change every single validation function, and in this example is really simple, because there is only 3 functions with the same validation, but imagine for one moment it is 100 functions where you perform the same validation, now that is painful.

So just defining a new class, with the long value and the validation annotation, and using that class on every method, you removed code duplication, and also when your validation requirements change, applying changes in one single place, you have mantained the code.

Also, there is nothing wrong about having to define classes for one specific task, in fact, that is exactly what Single Responsability Principle tells you to do.

Edit: added a link to a SRP description.