Rename handler to the correct name.

It's been too long since the electronics class in college, I guess.

Author: Marcelo Vanzin

network/common/src/main/java/org/apache/spark/network/TransportContext.java

@@ -30,8 +30,8 @@
 import org.apache.spark.network.client.TransportClientFactory;
 import org.apache.spark.network.client.TransportResponseHandler;
 import org.apache.spark.network.protocol.MessageDecoder;
-import org.apache.spark.network.protocol.MessageDemux;
 import org.apache.spark.network.protocol.MessageEncoder;
+import org.apache.spark.network.protocol.MessageMuxer;
 import org.apache.spark.network.server.RpcHandler;
 import org.apache.spark.network.server.TransportChannelHandler;
 import org.apache.spark.network.server.TransportRequestHandler;
@@ -104,7 +104,7 @@ public TransportChannelHandler initializePipeline(SocketChannel channel) {
     try {
       TransportChannelHandler channelHandler = createChannelHandler(channel);
       channel.pipeline()
-        .addLast("demux", new MessageDemux())
+        .addLast("muxer", new MessageMuxer())
         .addLast("encoder", encoder)
         .addLast("frameDecoder", NettyUtils.createFrameDecoder())
         .addLast("decoder", decoder)

network/common/src/main/java/org/apache/spark/network/protocol/MessageDemux.java renamed to network/common/src/main/java/org/apache/spark/network/protocol/MessageMuxer.java

@@ -30,7 +30,7 @@
  * processed by the pipeline stages properly, by being passed down as a list of buffers until
  * the very last handler (this one).
  */
-public final class MessageDemux extends ChannelOutboundHandlerAdapter {
+public final class MessageMuxer extends ChannelOutboundHandlerAdapter {
 
   private final Object lock = new Object();
 

network/common/src/test/java/org/apache/spark/network/ProtocolSuite.java

@@ -23,7 +23,7 @@
 import static org.junit.Assert.assertEquals;
 
 import org.apache.spark.network.protocol.Message;
-import org.apache.spark.network.protocol.MessageDemux;
+import org.apache.spark.network.protocol.MessageMuxer;
 import org.apache.spark.network.protocol.StreamChunkId;
 import org.apache.spark.network.protocol.ChunkFetchRequest;
 import org.apache.spark.network.protocol.ChunkFetchFailure;
@@ -37,7 +37,7 @@
 
 public class ProtocolSuite {
   private void testServerToClient(Message msg) {
-    EmbeddedChannel serverChannel = new EmbeddedChannel(new MessageDemux(), new MessageEncoder());
+    EmbeddedChannel serverChannel = new EmbeddedChannel(new MessageMuxer(), new MessageEncoder());
     serverChannel.writeOutbound(msg);
 
     EmbeddedChannel clientChannel = new EmbeddedChannel(
@@ -52,7 +52,7 @@ private void testServerToClient(Message msg) {
   }
 
   private void testClientToServer(Message msg) {
-    EmbeddedChannel clientChannel = new EmbeddedChannel(new MessageDemux(), new MessageEncoder());
+    EmbeddedChannel clientChannel = new EmbeddedChannel(new MessageMuxer(), new MessageEncoder());
     clientChannel.writeOutbound(msg);
 
     EmbeddedChannel serverChannel = new EmbeddedChannel(