Scala: ローンパターン1

gistfile1.scala

import collection.JavaConversions._
import java.net.URL
import org.apache.commons.io.IOUtils

object scalatest
{
  final class CloseableLike[T1 <: {def close(): Unit}](val a: T1) {
    def withClose[T2](f: T1 => T2): T2 = {
      try {
        f(a)
      } finally {
        try { a.close() } catch { case _ => () }
      }
    }
  }
  implicit def closeable2CloseableLike[T <: {def close(): Unit}](x: T): CloseableLike[T] = new CloseableLike(x)

  def main(args: Array[String])
  {
    new URL("http://www.google.com/").openStream.withClose(s => {
      println(IOUtils.toString(s, "UTF-8"))
    })
  }
}