Here is the solution to the complex domain modeling problem with Mapper
import net.liftweb.mapper._
trait Position extends BaseLongKeyedMapper {
type ContentType <: LongKeyedMapper[ContentType] with Positionable
def foreign: LongKeyedMetaMapper[ContentType]
def isMoving():Boolean = scheduled.obj.map(_ => true).openOr(false) ||
content.obj.map(_.isMoving()).openOr(false)
object role extends MappedString(this.asInstanceOf[MapperType],18)
object content extends MappedLongForeignKey(this
.asInstanceOf[MapperType],foreign)
object scheduled extends MappedLongForeignKey(this
.asInstanceOf[MapperType],foreign)
}
trait Positionable extends BaseLongKeyedMapper {
type ContainerType <: LongKeyedMapper[ContainerType] with Position
def foreign: LongKeyedMetaMapper[ContainerType]
def isMoving(): Boolean = dest.obj.map(_ => true).openOr(false) ||
container.obj.map(_.isMoving()).openOr(false)
object name extends MappedString(this.asInstanceOf[MapperType],32)
object container extends MappedLongForeignKey(this.asInstanceOf[
MapperType],foreign)
object dest extends MappedLongForeignKey(this.asInstanceOf[MapperType],
foreign)
}
class Pallet extends LongKeyedMapper[Pallet] with Positionable with IdPK {
type ContainerType = PalletPosition
def getSingleton = PalletMeta
def foreign = PalletPositionMeta
}
object PalletMeta extends Pallet with LongKeyedMetaMapper[Pallet]
class PalletPosition extends LongKeyedMapper[PalletPosition] with Position
with IdPK {
type ContentType = Pallet
def getSingleton = PalletPositionMeta
def foreign = PalletMeta
}
object PalletPositionMeta extends PalletPosition with LongKeyedMetaMapper[
PalletPosition]
Scala programming is too fun.
Regards
Giuseppe Fogliazza
beppe61 <[email protected]>
26/02/2009 20.08
Per favore, rispondere a
[email protected]
Per
Lift <[email protected]>
CC
Oggetto
[Lift] Using Traits in complex domain models
In a new project to support Manufacturing Operations, using Lift, I
want to code a common pattern for my application and hence I
introduced two traits implementing the basic relationship between a
Position and its content assumed as a Positionable. Concrete classes
will be persisted using Mapper.
Here my try:
trait Position extends BaseLongKeyedMapper {
type ContentType <: Positionable
def foreign: LongKeyedMetaMapper[ContentType]
def isMoving():Boolean = scheduled.obj.map(_ => true).openOr(false)
|| content.obj.map(_.isMoving()).openOr(false)
object role extends MappedString(this.asInstanceOf[MapperType],18)
object content extends MappedLongForeignKey(this.asInstanceOf
[MapperType],foreign) // type mismatch
object scheduled extends MappedLongForeignKey(this.asInstanceOf
[MapperType],foreign) // type mismatch
}
trait Positionable extends BaseLongKeyedMapper {
type ContainerType <: Position
def foreign: LongKeyedMetaMapper[ContainerType]
def isMoving(): Boolean = dest.obj.map(_=>true).openOr(false)
object name extends MappedString(this.asInstanceOf[MapperType],32)
object position extends MappedLongForeignKey(this.asInstanceOf
[MapperType],foreign) // type mismatch
object dest extends MappedLongForeignKey(this.asInstanceOf
[MapperType],foreign) // type mismatch
}
I would like to declare a concrete class this way:
class Pallet extends LongKeyedMapper[Pallet] with Positionable with
IdPK {
type ContainerType = PalletPosition
def getSingleton = PalletMeta
def foreign = PalletPositionMeta
}
object PalletMeta extends Pallet with LongKeyedMetaMapper[Pallet]
class PalletPosition extends LongKeyedMapper[PalletPosition] with
Position with IdPK {
type ContentType = Pallet
def getSingleton = PalletPositionMeta
def foreign = PalletMeta
}
object PalletPositionMeta extends PalletPosition with
LongKeyedMetaMapper[PalletPosition]
Unfortunately there is a type mismatch in parameters passed to
MappedLongForeignKey in the Position and Positionable traits.
Do you have any suggestion?
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