@Entity
    @Name("hotel")
    class Hotel implements Serializable
    {
        @Id @GeneratedValue
        Long id

        @Length(max=50) @NotNull
        String name

        @Length(max=100) @NotNull
        String address

        @Length(max=40) @NotNull
        String city

        @Length(min=2, max=10) @NotNull
        String state

        @Length(min=4, max=6) @NotNull
        String zip

        @Length(min=2, max=40) @NotNull
        String country

        @Column(precision=6, scale=2)
        BigDecimal price

        @Override
        String toString()
        {
            return "Hotel(${name},${address},${city},${zip})"
        }
    }

Groovy natively support the notion of properties (getter/setter), so there is no need to explicitly write verbose getters and setters: in the previous example, the hotel class can be accessed from Java as hotel.getCity(), the getters and setters being generated by the Groovy compiler. This type of syntactic sugar makes the entity code very concise.

Some temporary gotchas: Groovy 1.1 Beta1 does not (yet) support generics. One negative effect of this is that entity relationships have no built-in type information. It is necessary to use the targetEntity attribute of the appropriate @*ToMany annotation instead of simply using a generic type definition like Collection<Entity>. For the same reason, you won't be able to benefit from the very useful Chapter 11, The Seam Application Framework yet. The good news is that support for generics is targeted for Groovy 1.1 (Groovy 1.1 Beta2 at the time of writing).

Writing Seam components in Groovy is in no way different than in Java: annotations are used to mark the class as a Seam component.

@Scope(ScopeType.SESSION)
@Name("bookingList")
class BookingListAction implements Serializable
{
    @In EntityManager em
    @In User user
    @DataModel List<Booking> bookings
    @DataModelSelection Booking booking
    @Logger Log log

    @Factory public void getBookings()
    {
        bookings = em.createQuery('''
                select b from Booking b
                where b.user.username = :username
                order by b.checkinDate''')
            .setParameter("username", user.username)
            .getResultList()
    }
    
    public void cancel()
    {
        log.info("Cancel booking: #{bookingList.booking.id} for #{user.username}")
        Booking cancelled = em.find(Booking.class, booking.id)
        if (cancelled != null) em.remove( cancelled )
        getBookings()
        FacesMessages.instance().add("Booking cancelled for confirmation number #{bookingList.booking.id}", new Object[0])
    }
}