Connect to remote host Finagle / Netty

gistfile1.scala

private[netty3] class ChannelConnector[In, Out]( 
  newChannel: () => Channel,
  newTransport: Channel => Transport[In, Out]
) extends (SocketAddress => Future[Transport[In, Out]]) {
  def apply(addr: SocketAddress): Future[Transport[In, Out]] = {		
  require(addr != null)
val ch = try newChannel() catch {		
  case NonFatal(exc) => return Future.exception(exc) #1 
}				
 // Transport is now bound to the channel; this is done prior to
 // it being connected so we don't lose any messages.
 val transport = newTransport(ch) #2 val connectFuture = ch.connect(addr) #3 
 val promise = new Promise[Transport[In, Out]] #4 
 promise setInterruptHandler { case _cause =>				
   // Propagate cancellations onto the netty future.	
   connectFuture.cancel() 
 }		
 connectFuture.addListener(new ChannelFutureListener {
   def operationComplete(f: ChannelFuture) { #5		
     if (f.isSuccess) { 
         promise.setValue(transport) 
     } else if (f.isCancelled) {
         promise.setException(
         WriteException(new CancelledConnectionException)) 
     } else {					
         promise.setException(WriteException(f.getCause)) }
       } 
    })
    promise onFailure { _ =>
      Channels.close(ch) 
    }					
  }				
}
// #1 Try to create a new Channel. If it fails wrap the exception in a Future and return immediately
// #2 Create a new Transport with the Channel
// #3 Connect the remote host asynchronously. The returned ChannelFuture will be notified once the connection completes
// #4 Create a new Promise which will be notified once the connect attempt finished
// #5 Handle the completion of the connectFuture by fulfilling the created promise