Validation one field against another

vlarchet · **Joined:** Wed Sep 19, 2007 10:05 am **Posts:** 3

Hi,

I have quite a simple issue:
One entity (let's name it History) has 2 fields:
Date validFrom;
Date validTo;

I want to ensure that validTo is after validFrom.

My first idea was to define my own field validator that I put on validTo but I can only access the value from the property itself, thus not possible to inspect validFrom...

Of course I can write a method like that:
@AssertTrue
public boolean validateToAfterFrom() {
return validTo.after(validFrom);
}

but then, the validation is entity wide and I cannot know on my screen that I have to write an error message near validTo specifically...

Any solution to this problem that seems really standard ??
(either be able to inspect the whole entity or be able to specify on which field an AssertTrue function works)

Thx very much

vincent

Hibernate version: 3.2.2 GA
Hibernate Validator version: 3.0.0 GA

emmanuel · **Posted:** Mon Oct 01, 2007 11:34 am

you can use a bean level validator

vlarchet · **Joined:** Wed Sep 19, 2007 10:05 am **Posts:** 3

Thx for the answer, but...

With a bean level validator, I get for sure the whole bean in parameter, so I am able to do the validation, but it is not possible to state that a given field is in error... and this is the behavior you expect (excerpt from hibernate validator unit test:

Code:

public void testBeanValidator() throws Exception {
      Vase v = new Vase();
      ClassValidator<Vase> classValidator = new ClassValidator<Vase>( Vase.class );
      InvalidValue[] invalidValues = classValidator.getInvalidValues( v );
      assertEquals( 1, invalidValues.length );
      assertNull( invalidValues[0].getPropertyName() );//<<<<<<
   }

Note: this is the same issue as when using @AssertTrue on a method

I really need to validate ONE field, but for this validation, I need to access other fields...

One implementation suggestion (actually I already did it and it works fine...):
* add one interface

Code:

public interface ValidatorWholeBeanAware{}

* flag my validator with it:

Code:

public class MyValidator implements Validator<Assert>,ValidatorWholeBeanAware

* in ClassValidator around line 385 and 505 (methods= getInvalidValues(T, circ) and getInvalidValues(T, propertyName)):

replace

Code:

Object value = getMemberValue( bean, getter );

by

Code:

Object value=bean;
if (!(validator instanceof ValidatorWholeBeanAware)) {
   value = getMemberValue( bean, getter );
}

Then MyValidator is still a property level validator (ie, InvalidValue.getPropertyName() will return the field name) but it can access the whole bean...

What do you think of this implementation ?

Thx very much

vincent

emmanuel · **Posted:** Fri Oct 19, 2007 5:15 pm

The proposal is elegant but...
If you push your usecase, it's not really validating one field, it's really validating a tuple. You might want to give back a message like:

date from: 2005 should be older than date to: 2004

thus getPropertyName() not making much sense. Why do you need it (the property name)?