Play Framework/Scala example source code file (ParameterValue.scala)

This example Play Framework source code file (ParameterValue.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Play Framework (and Scala) source code examples by using tags.

All credit for the original source code belongs to Play Framework; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Play Framework tags/keywords

a, illegalargumentexception, int, mayerr, parametervalue, play, play framework, preparedstatement, string, tosql, tostatement, wrapper

The ParameterValue.scala Play Framework example source code

package anorm

import java.sql.PreparedStatement

/** Prepared parameter value. */
sealed trait ParameterValue {

  /**
   * Writes placeholder(s) in [[java.sql.PreparedStatement]] syntax
   * (with '?') for this parameter in initial statement (with % placeholder).
   *
   * @param stmt SQL statement (with %s placeholders)
   * @param offset Position offset for this parameter
   * @return Update statement with '?' placeholder(s) for parameter,
   * with offset for next parameter
   */
  def toSql(stmt: String, offset: Int): (String, Int)

  /**
   * Sets this value on given statement at specified index.
   *
   * @param s SQL Statement
   * @param index Parameter index
   */
  def set(s: PreparedStatement, index: Int): Unit
}

/**
 * Value factory for parameter.
 *
 * {{{
 * val param = ParameterValue("str", null, setter)
 *
 * SQL("...").onParams(param)
 * }}}
 */
object ParameterValue {
  import scala.language.implicitConversions

  private[anorm] trait Wrapper[T] { def value: T }

  @throws[IllegalArgumentException]("if value `v` is null whereas `toStmt` is marked with [[anorm.NotNullGuard]]") // TODO: MayErr on conversion to parameter values?
  def apply[A](v: A, s: ToSql[A], toStmt: ToStatement[A]) = (v, toStmt) match {
    case (null, _: NotNullGuard) => throw new IllegalArgumentException()
    case _ => new ParameterValue with Wrapper[A] {
      val value = v

      def toSql(stmt: String, o: Int): (String, Int) = {
        val frag: (String, Int) =
          if (s == null) ("?" -> 1) else s.fragment(value)

        Sql.rewrite(stmt, frag._1).fold[(String, Int)](
          /* ignore extra parameter */ stmt -> o)(rw =>
            (rw, o + frag._2))
      }

      def set(s: PreparedStatement, i: Int) = toStmt.set(s, i, value)

      override lazy val toString = s"ParameterValue($value)"
      override lazy val hashCode = value.hashCode

      override def equals(that: Any) = that match {
        case o: Wrapper[A] => (o.value == value)
        case _ => false
      }
    }
  }

  implicit def toParameterValue[A](a: A)(implicit s: ToSql[A] = null, p: ToStatement[A]): ParameterValue = apply(a, s, p)
}