Slick DAO Capabilities

gistfile1.scala

**
 * DAOCapabilities for slick entities.
 *
 * @author [email protected]
 * @since 4/14/14
 */
abstract class AbstractDAOCapabilities[ENTITY <: EntityCapabilities[ENTITY], TABLE <: AbstractTable[ENTITY]](cons: Tag => TABLE)

  extends DAOCapabilities[Option[Long], ENTITY]

  with LoggingCapabilities {

  import de.rodenstock.fue.commons.play.controllers.stackable.CurrentRequest._
  import scala.language.reflectiveCalls

  /**
   * Variable for entity name. It will be determined during initialization.
   */
  private var _entityName: String = _

  /**
   * Slick table query for the given table.
   */
  val entities = new TableQuery(initializeTableQuery) {
    val findById = this.findBy(_.id)
  }

  /**
   * Initializes the table and stores the tables name as class attribute. This function has side-effects!
   *
   * @param tag
   * The slick tag.
   * @return
   * The initialized table.
   */
  private def initializeTableQuery(tag: Tag): TABLE = {
    val table = cons(tag)
    _entityName = table.tableName
    table
  }

  /**
   * @return The display name of the entity (used for logging, generic ui, ...)
   */
  def entityName = if (_entityName == null) {
    throw andLog(new IllegalStateException("The entity name is not defined yet - Something went wrong."))
  } else {
    _entityName
  }

  /**
   * Companion method to insert or update an entity (depending if it's already stored or not).
   *
   * @param entity
   * The entity to be stored.
   * @param request
   * The current request context.
   * @return
   * The saved entity.
   */
  override def save(entity: ENTITY)(implicit request: RequestWithAttributes[_]): ENTITY = {
    // We need to store entity.id in a value, since the generic Long of ID_TYPE will get lost due to type erasure.
    val id: Option[Long] = entity.id
    id match {
      case Some(_) => update(entity)
      case None => insert(entity)
    }
  }

  /**
   * Deletes an existing entity.
   *
   * @param id
   * The id of the entity which should be deleted.
   * @param request
   * The current request context.
   * @return
   */
  override def deleteById(id: Option[Long])(implicit request: RequestWithAttributes[_]): Unit = {
    entities.where(_.id === id).delete
  }

  /**
   * Deletes an existing entity.
   *
   * @param entity
   * The entity which should be deleted.
   * @param request
   * The current request context.
   * @return
   */
  override def delete(entity: ENTITY)(implicit request: RequestWithAttributes[_]): Unit = deleteById(entity.id)

  /**
   * Update an existing entity.
   * @param entity
   * The entity to update.
   * @param request
   * The current request context.
   * @return
   * The updated entity.
   */
  override def update(entity: ENTITY)(implicit request: RequestWithAttributes[_]): ENTITY = {
    // We need to store entity.id in a value, since the generic Long of ID_TYPE will get lost due to type erasure.
    val id: Option[Long] = entity.id
    id match {
      case Some(_) =>
        entities.where(_.id === entity.id).update(entity)
        entity
      case None =>
        throw andLog(new IllegalArgumentException("Entity ID is not defined. Update must be called with an already stored entity."))
    }
  }

  /**
   * Get a list of all available entities.
   *
   * @param request
   * The current request context.
   * @return
   * The list of all available entities.
   */
  override def list(implicit request: RequestWithAttributes[_]): Seq[ENTITY] = entities.list

  /**
   * Insert a new entity.
   *
   * @param entity
   * The entity to insert.
   * @param request
   * The current request context.
   * @return
   * The inserted entity.
   */
  override def insert(entity: ENTITY)(implicit request: RequestWithAttributes[_]): ENTITY = {
    // We need to store entity.id in a value, since the generic Long of ID_TYPE will get lost due to type erasure.
    val id: Option[Long] = entity.id
    id match {
      case Some(_) =>
        throw andLog(new IllegalArgumentException("Entity ID is already defined. Insert must be called with a new entity."))
      case None =>
        val newId = (entities returning entities.map(_.id)) += entity
        entity.withId(Some(newId))
    }
  }

  /**
   * Return the count of all existing entities.
   *
   * @param request
   * The current request context.
   * @return
   * The calculated count of existing entities.
   */
  override def count(implicit request: RequestWithAttributes[_]): Int = list.size

  /**
   * Find the attribute by its id.
   *
   * @param id
   * The id to look for.
   * @param request
   * The current request context.
   * @return
   * Some entity if it exists, else None.
   */
  override def findById(id: Option[Long])(implicit request: RequestWithAttributes[_]): Option[ENTITY] = entities.findById(id.get).firstOption

}