validation.addValidator(new MinLengthValidator(Customer.class,
"username", USERNAME_MINLENGTH));
validation.addValidator(new MaxLengthValidator(Customer.class,
"username", USERNAME_MAXLENGTH));
validation.addValidator(new RegExpValidator(Customer.class,
"emailAddress", EMAILADDRESS_REGEXP));
validation.addValidator(new NotNullValidator(Customer.class,
"discountPercentage"));
validation.addValidator(new MinValueValidator(Customer.class,