It would be great if we could also do the same thing with Properties. Have
a @Property annotation so that we don't have to do the same thing with the
Location.name. And how about ManyAssociations?
In general, I'd like to see this be the direction things go in because the
Property<type>, Association<type> and ManyAssociation<type> have always
seemed a little invasive.
Rich
On Fri, Oct 24, 2008 at 9:29 AM, Edward Yakop <[EMAIL PROTECTED]>wrote:
> Hi,
>
> I think we need to introduce another mechanism to declare property and
> association.
> Let's look at dddsample and try to implement Cargo model.
>
> If I want to retain exactly the same Cargo interface:
> <code>
> public interface Cargo
> {
> Location origin();
>
> Location destination();
>
> void changeDestination( @NotNull Location newDestination );
>
> ...
> }
> </code>
>
> To make Cargo persistable, I need to create a mixin type.
> <code>
> public interface CargoState
> {
> // Unfortunately the name has to be done this way, because our
> entity will implement both CargoState and Cargo
> Association<Location> originAssociation();
> Association<Location> destinationAssociation();
> }
> </code>
>
> And the entity
> <code>
> @Mixins( CargoEntity.CargoMixin.class )
> public interface CargoEntity extends Cargo, CargoState, EntityComposite
> {
> class CargoMixin implements CargoEntity
> {
> public final Location origin()
> {
> return orginAssociation.get();
> }
>
> Location destination()
> {
> return destinationAssociation.get();
> }
>
> public void changeDestination( @NotNull Location newDestination )
> {
> return destinationAssociation.set( newDestination );
> }
> }
> }
> </code>
>
> If I have to do this very same thing for every model. I might as well
> forget about my productivity.
> Adding/Removing property and association is definitely painfull.
>
> But, if we support this
> <code>
> public interface Cargo
> {
> @Association
> Location origin();
>
> @Association
> Location destination();
>
> void changeDestination( @NotNull Location newDestination );
>
> ...
> }
> </code>
>
> We can reduce the entity implementation to
> <code>
> @Mixins( CargoEntity.CargoMixin.class )
> public interface CargoEntity extends Cargo, EntityComposite
> {
> class CargoMixin implements CargoEntity
> {
> @AssociationField private Association<Location> destination;
>
> public void changeDestination( @NotNull Location newDestination )
> {
> return destination.set( newDestination );
> }
> }
> }
> </code>
> I would not need to care implementing Cargo#origin() and
> Cargo#association().
> Because I already put a @Association annotation.
>
> If I want to implement concern/side effect on the setters or getters
> of these association,
> this becomes very trivial to do.
>
> How about creational?
>
> EntityBuilder<Cargo> builder = ...;
> Cargo cargoTemplate = builder.template();
> builder.initialize( cargoTemplate.origin() ).set( origin );
> builder.initialize( cargoTemplate.destination() ).set( destination );
>
> Query would be done in similar manner.
>
> wdyt?
>
> Regards,
> Edward Yakop
>
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>
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