DefaultValue.scala

trait DefaultValue[T] {
  def value: T
}
object DefaultValue {
  implicit object DefaultByteValue extends DefaultValue[Byte] {
    def value: Byte = 0
  }
  implicit object DefaultShortValue extends DefaultValue[Short] {
    def value: Short = 0
  }
  implicit object DefaultCharValue extends DefaultValue[Char] {
    def value: Char = 0
  }
  implicit object DefaultIntValue extends DefaultValue[Int] {
    def value: Int = 0
  }
  implicit object DefaultLongValue extends DefaultValue[Long] {
    def value: Long = 0L
  }
  implicit object DefaultFloatValue extends DefaultValue[Float] {
    def value: Float = 0.0f
  }
  implicit object DefaultDoubleValue extends DefaultValue[Double] {
    def value: Double = 0.0
  }
  implicit object DefaultBooleanValue extends DefaultValue[Boolean] {
    def value: Boolean = false
  }
  private val defaultValueCache = new DefaultValue[AnyRef] {
    def value: AnyRef = null
  }
  //To avoid creation of DefaultValue[AnyRef] instance.
  implicit def DefaultAnyRef[T >: Null <: AnyRef]: DefaultValue[T] = {
    defaultValueCache.asInstanceOf[DefaultValue[T]]
  }
  def default[T:DefaultValue]: T = implicitly[DefaultValue[T]].value
}