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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