Initializes the validator in preparation for {@link #isValid(Object, ConstraintValidatorContext)} calls. The constraint annotation for a given constraint declaration is passed. <p> This method is guaranteed to be called before any use of this instance for validation. <p> The default implementation is a no-op.
Implements the validation logic. The state of {@code value} must not be altered. <p> This method can be accessed concurrently, thread-safety must be ensured by the implementation.