Slick select using value object (extending AnyVal) - scala

Question

I am using Slick 2.1.0 with Scala 2.10.
I have a value object (EMail) that I map to a VARCHAR column.
object EMail {
import java.util.regex.Pattern
val emailRegex = Pattern.compile("^[A-Z0-9._%+-]+#[A-Z0-9.-]+\\.[A-Z]{2,6}$", Pattern.CASE_INSENSITIVE)
val empty = EMail("x#y.com")
}
case class EMail(value: String) extends AnyVal with MappedTo[String] {
def isValid: Boolean = EMail.emailRegex.matcher(value).find
def validate: EMail = {
assert(isValid)
EMail(value.trim.toLowerCase)
}
override def toString = validate.value
}
The Column definition is:
def email = column[Option[EMail]]("email_address")
This is my attempt at writing a finder:
def findByEmail(email: Option[EMail]): Option[User] =
database.withSession { implicit session: Session =>
queryAll.filter(e => e.email.isDefined && e.email === email).firstOption
}
This is the error message I get:
[error] Users.scala:52: ambiguous implicit values:
[error] both value BooleanCanBeQueryCondition in object CanBeQueryCondition of type => scala.slick.lifted.CanBeQueryCondition[Boolean]
[error] and value BooleanOptionColumnCanBeQueryCondition in object CanBeQueryCondition of type => scala.slick.lifted.CanBeQueryCondition[scala.slick.lifted.Column[Option[Boolean]]]
[error] match expected type scala.slick.lifted.CanBeQueryCondition[Nothing]
[error] queryAll.filter(_.email === email.map(_.value)).firstOption
[error] ^

Answer 1

You don't have to pass an Option[EMail] to your method, you could simply make:
def findByEmail(email: EMail): Option[User] = {
database.withSession { implicit session =>
queryAll.filter(_.email === email).firstOption
}
}
If you really need an Option[EMail]] as the input parameter, you should try the following:
def findByEmail(emailOpt: Option[EMail]): Option[User] = {
emailOpt.flatMap { email =>
database.withSession { implicit session =>
queryAll.filter(_.email === email).firstOption
}
}
}