Slick2 generic dao

gistfile1.scala

package slicks.docs.dao

import scala.slick.driver.PostgresDriver.simple._
import scala.slick.driver._


trait Profile {
  val profile: JdbcProfile
}

trait CrudComponent {
  this: Profile =>

  abstract class Crud[T <: Table[E] with IdentifiableTable[PK], E <: Entity[PK], PK: BaseColumnType](implicit session: Session) {

    val query: TableQuery[T]

    def count: Int = {
      query.length.run
    }

    def findAll: List[E] = {
      query.list()
    }

    def queryById(id: PK) = query.filter(_.id === id)
    
    def findOne(id: PK): Option[E] = queryById(id).firstOption
    
    def add(m: E): PK = (query returning query.map(_.id)) += m 
    
    def withId(model: E, id: PK): E 
    
    def extractId(m: E): Option[PK] = m.id
    
    def save(m: E): E = extractId(m) match {
      case Some(id) => {
        queryById(id).update(m)
        m
      }
      case None => withId(m, add(m))
    }
    
    def saveAll(ms: E*): Option[Int] = query ++= ms
    
    def deleteById(id: PK): Int = queryById(id).delete
    
    def delete(m: E): Int = extractId(m) match {
      case Some(id) => deleteById(id)
      case None => 0
    }
        
  }
}

trait Entity[PK] {
  def id: Option[PK]
}

trait IdentifiableTable[I] {
  def id: Column[I]
}


package slicks.docs

import slicks.docs.dao.{Entity, IdentifiableTable, CrudComponent, Profile}


case class User(id: Option[Long], first: String, last: String) extends Entity[Long]

trait UserComponent extends CrudComponent {
  this: Profile =>

  import profile.simple._

  class UsersTable(tag: Tag) extends Table[User](tag, "users") with IdentifiableTable[Long] {

    override def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
    def first = column[String]("first")
    def last = column[String]("last")

    def * = (id.?, first, last) <> (User.tupled, User.unapply)

  }

  class UserRepository(implicit session: Session) extends Crud[UsersTable, User, Long] {

    override def query = TableQuery[UsersTable]

    override def withId(user: User, id: Long): User = user.copy(id = Option(id))
  }
}