Bean Validation Constraints in address-book

The Contact entity uses the @NotNull, @Pattern, and @Past constraints on the persistent attributes.

The @NotNull constraint marks the attribute as a required field. The attribute must be set to a non-null value before the entity can be persisted or modified. Bean Validation will throw a validation error if the attribute is null when the entity is persisted or modified.

The @Pattern constraint defines a regular expression that the value of the attribute must match before the entity can be persisted or modified. This constraint has two different uses in address-book.

• The regular expression declared in the @Pattern annotation on the email field matches email addresses of the form name@domain name.top level domain, allowing only valid characters for email addresses. For example, username@example.com will pass validation, as will firstname.lastname@mail.example.com. However, firstname,lastname@example.com, which contains an illegal comma character in the local name, will fail validation.

• The mobilePhone and homePhone fields are annotated with a @Pattern constraint that defines a regular expression to match phone numbers of the form (xxx) xxx–xxxx.

The @Past constraint is applied to the birthday field, which must be a java.util.Date in the past.

Here are the relevant parts of the Contact entity class:

@Entity
public class Contact implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @NotNull
    protected String firstName;
    @NotNull
    protected String lastName;
    @Pattern(regexp="[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\."
        +"[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*"
        +"@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?",
             message="{invalid.email}")
    protected String email;
    @Pattern(regexp="^\\(?(\\d{3})\\)?[- ]?(\\d{3})[- ]?(\\d{4})$",
             message="{invalid.phonenumber}")
    protected String mobilePhone;
    @Pattern(regexp="^\\(?(\\d{3})\\)?[- ]?(\\d{3})[- ]?(\\d{4})$",
             message="{invalid.phonenumber}")
    protected String homePhone;
    @Temporal(javax.persistence.TemporalType.DATE)
    @Past
    protected Date birthday;
    ...
}