Blog Scala API Document Implicit Parameter sample code. http://blog.joecwu.com/2015/07/scava-scala-scala-api-document-implicit.html

blog-ScalaAPIDocument-implicit-parameter.scala

case class TracerId(tid:String)
object TestApp {
  implicit val tracerId = TracerId(java.util.UUID.randomUUID().toString) // tracerId can be defined and retrieved from HTTP request header.
  
  def run(){
    methodA(1)
    methodB
  }
  
  def methodA(i:Int)(implicit tracerId:TracerId) = {
    println(s"A: I have tracerId:[$tracerId].")
  }
  
  def methodB(implicit tracerId:TracerId) = {
    println(s"B: I have tracerId:[$tracerId].")
    methodC("YOYO")
  }
  
  def methodC(str:String)(implicit tracerId:TracerId) = {
    println(s"C: I have tracerId:[$tracerId] as well.")
  }
}