Java's try-with-resources pattern, but in Scala.

tryWIthResources.scala

trait SourceUtils {

  /**
    * Opens a `resource`, passes it to the given function `f`, then
    * closes the resource, returning the value returned from `f`.
    * 
    * Example usage:
    * {{{
    * val myString: String =
    *   using(scala.io.Source.fromFile("file.name")) { source =>
    *     source.getLines.mkString
    *   }
    * }}}
    * 
    * @param resource closeable resource to use, then close
    * @param f function which maps the resource to some return value
    * @tparam T type of the resource to be opened / closed
    * @tparam U type of the return value
    * @return the result of the function `f`
    */
  def using[T <: AutoCloseable, U](resource: => T)(f: T => U): U = {
    scala.util.Try(resource).fold(throw _, source => {
      val result = f(source)
      source.close()
      result
    })
  }
}