Hibernate.orgCommunity Documentation  Chapter 6. Creating custom
constraints  6.1. Creating a simple constraint 6.1.1. The
constraint annotation 6.1.2. The constraint validator 6.1.3. The
error message 6.1.4. Using the constraint 6.2. Class-level
constraints 6.2.1. Custom property paths 6.3. Cross-parameter
constraints 6.4. Constraint composition  The Bean Validation API
defines a whole set of standard constraint annotations such as
@NotNull, @Size etc. In cases where these buit-in constraints
are not sufficient, you cean easily create custom constraints
tailored to your specific validation requirements.  To create a
custom constraint, the following three steps are required:  This
section shows how to write a constraint annotation which can be
used to ensure that a given string is either completely upper
case or lower case. Later on this constraint will be applied to
the licensePlate field of the Car class from Chapter 1, Getting
started to ensure, that the field is always an upper-case
string.  The first thi