helper "use" method using currying for automatic resource management From http://stackoverflow.com/questions/2225214/scala-script-to-copy-files

new_gist_file

If you really want to do it yourself instead of using a library like commons-io, you can do the following in version 2.8. Create a helper method "use". It will give you a form of automatic resource management.

def use[T <: { def close(): Unit }](closable: T)(block: T => Unit) {
  try {
    block(closable)
  }
  finally {
    closable.close()
  }
}
Then you can define a copy method like this:

import java.io._

@throws(classOf[IOException])
def copy(from: String, to: String) {
  use(new FileInputStream(from)) { in =>
    use(new FileOutputStream(to)) { out =>
      val buffer = new Array[Byte](1024)
      Iterator.continually(in.read(buffer))
          .takeWhile(_ != -1)
          .foreach { out.write(buffer, 0 , _) }
    }
  }
}
Note that the buffer size (here: 1024) might need some tuning.

share|improve this answer
answered Jun 12 '10 at 13:40

Ruediger Keller
1,309612