Question

So I have a String I need to check for a valid format for which I used a pattern, and whether the entered value is valid according to some business rules for which I used a custom validator. Now the customer would prefer it if the error message associated with the latter is only shown if the former didn’t occur. But as far as I know there is no way to make this distinction.
Or can anyone think of a way to do this?

Answer 1

The trick is: have two different constraints (annotations),

• one for the pattern, that accept null,
• and a second for not null.

By default the javax.validation.constraints.Pattern “validator” accept null.

Accepts String. null elements are considered valid.
(javax.validation.constraints.Pattern javadoc)

So what you need to do in the end is this:

@NotNull(message="{validation.notNull}")
@Pattern(pattern="123" message="{validation.notPattern}")
String myString;

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Added:

(Comment)

Not really the desired behaviour since I want to reuse the bean object but the conditions aren’t the same for each page. – Jack Nickels 5 mins ago

In this case you can use the so called groups (See JSR303 Bean Validation Spec, Chapter 4.1.2 groups — there is also an example). Use the default Group for @Pattern and an other group for @NotNull. Now you can enable or disable the Validation rules according the groups you specify for validation.

validator.validate(myObject, Default.class);
validator.validate(myObject, MyGroup.class);

There is one problem left: in Spring 3.0 you can not Specify the Group you want to use for the automatic validation process. But in 3.1 you can, according to that Feature Request SPR-6373 (I have not tryed it, but I hope it works)