Is possible to set validation order with Hibernate Validator?

Question

Hi all.

I use @AssertTrue annotation to ensure the execution of a method that sets some default values (always returns true). These set values are validated as @NotEmpty (these are Strings). So I need to guarantee that method annotated with @AssertTrue is executed strictly before that fields annotated with @NotEmpty.

Simplified code example (not included Hibernate annotations):

public class MyClass {
   @NotEmpty
   private String myField = null;

   @SuppressWarnings("unused")
   @AssertTrue
   private boolean fillDefaultValues() {

      if (this.myField == null) {
         this.myField = "default value";
      }

      return true;
   }
}

Answer 1

This seems to me like a hack. For two reasons:

• you always return true and assert it for the sole purpose of executing an initialization code
• you expect the framework to access and validate your bean in a specific order in order to execute an initialization code

The thing in common is "initialization code". In order to achieve what you want, you can register a listener and execute the initialization method before the validation happens. Here's the documentation of hibernate-validator - it tells you about event listeners.

You can also manually set the default values in your service layer (since you seem to be using anemic data model). Since this seems like a business logic, it'd better be in the service method, before the object is persisted.

Answer 2

Finally I have solved my problem.

Debuging validator stack trace, I have seen that first it process beanValidators, and then, memberValidators. So the only I have to do is define my initialization code in a class constraint.

I have defined a new class annotation where, depending on the type of the pojo received, I set default values.

I have verified that this code is executed before than any other (member) constarint, like @NotEmpty, etc.