Cleaned up chaining of ChannelGroupFutures

akka-remote/src/main/scala/akka/remote/transport/netty/NettyTransport.scala

@@ -11,9 +11,9 @@ import com.typesafe.config.Config
 import java.net.{ UnknownHostException, SocketAddress, InetAddress, InetSocketAddress, ConnectException }
 import java.util.concurrent.{ ConcurrentHashMap, Executor, Executors, CancellationException }
 import org.jboss.netty.bootstrap.{ ConnectionlessBootstrap, Bootstrap, ClientBootstrap, ServerBootstrap }
-import org.jboss.netty.buffer.{ChannelBuffers, ChannelBuffer}
+import org.jboss.netty.buffer.{ ChannelBuffers, ChannelBuffer }
 import org.jboss.netty.channel._
-import org.jboss.netty.channel.group.{ ChannelGroupFuture, ChannelGroupFutureListener }
+import org.jboss.netty.channel.group.{ ChannelGroup, ChannelGroupFuture, ChannelGroupFutureListener }
 import org.jboss.netty.channel.socket.nio.{ NioDatagramChannelFactory, NioServerSocketChannelFactory, NioClientSocketChannelFactory }
 import org.jboss.netty.handler.codec.frame.{ LengthFieldBasedFrameDecoder, LengthFieldPrepender }
 import scala.concurrent.duration.{ Duration, FiniteDuration, MILLISECONDS }
@@ -41,6 +41,20 @@ object NettyFutureBridge {
     })
     p.future
   }
+
+  def apply(nettyFuture: ChannelGroupFuture): Future[ChannelGroup] = {
+    import scala.collection.JavaConverters._
+    val p = Promise[ChannelGroup]
+    nettyFuture.addListener(new ChannelGroupFutureListener {
+      def operationComplete(future: ChannelGroupFuture): Unit = p complete Try(
+        if (future.isCompleteSuccess) future.getGroup
+        else throw future.iterator.asScala.collectFirst {
+          case f if f.isCancelled ⇒ new CancellationException
+          case f if !f.isSuccess  ⇒ f.getCause
+        } getOrElse new IllegalStateException("Error reported in ChannelGroupFuture, but no error found in individual futures."))
+    })
+    p.future
+  }
 }
 
 class NettyTransportException(msg: String, cause: Throwable) extends RuntimeException(msg, cause) with OnlyCauseStackTrace {
@@ -348,21 +362,13 @@ class NettyTransport(private val settings: NettyTransportSettings, private val s
   }
 
   override def shutdown(): Unit = {
-    // Force flush by trying to write an empty buffer and wait for success
-    channelGroup.write(ChannelBuffers.buffer(0)).addListener(new ChannelGroupFutureListener {
-      def operationComplete(future: ChannelGroupFuture) {
-        channelGroup.unbind()
-        channelGroup.disconnect().addListener(new ChannelGroupFutureListener {
-          def operationComplete(future: ChannelGroupFuture) {
-            channelGroup.close().addListener(new ChannelGroupFutureListener {
-              def operationComplete(future: ChannelGroupFuture) {
-                inboundBootstrap.releaseExternalResources()
-              }
-            })
-          }
-        })
-      }
-    })
+    def always(c: ChannelGroupFuture) = NettyFutureBridge(c) recover { case _ ⇒ c.getGroup }
+    for {
+      // Force flush by trying to write an empty buffer and wait for success
+      _ ← always(channelGroup.write(ChannelBuffers.buffer(0)))
+      _ ← always({ channelGroup.unbind(); channelGroup.disconnect() })
+      _ ← always(channelGroup.close())
+    } inboundBootstrap.releaseExternalResources()
 
   }
 

akka-remote/src/main/scala/akka/remote/transport/netty/UdpSupport.scala

@@ -35,7 +35,7 @@ private[remote] trait UdpHandlers extends CommonHandlers {
       } else {
         val listener = transport.udpConnectionTable.get(inetSocketAddress)
         val bytes: Array[Byte] = e.getMessage.asInstanceOf[ChannelBuffer].array()
-        if (bytes.length > 0)listener notify InboundPayload(ByteString(bytes))
+        if (bytes.length > 0) listener notify InboundPayload(ByteString(bytes))
       }
     case _ ⇒
   }