No need to pass the next BufType to the constructor

codec/src/main/java/io/netty/handler/codec/string/StringEncoder.java

@@ -15,7 +15,6 @@
  */
 package io.netty.handler.codec.string;
 
-import io.netty.buffer.BufType;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandler.Sharable;
@@ -50,44 +49,41 @@ import java.nio.charset.Charset;
 @Sharable
 public class StringEncoder extends ChannelOutboundMessageHandlerAdapter<CharSequence> {
 
-    private final BufType nextBufferType;
     // TODO Use CharsetEncoder instead.
     private final Charset charset;
 
     /**
      * Creates a new instance with the current system character set.
      */
-    public StringEncoder(BufType nextBufferType) {
-        this(nextBufferType, Charset.defaultCharset());
+    public StringEncoder() {
+        this(Charset.defaultCharset());
     }
 
     /**
      * Creates a new instance with the specified character set.
      */
-    public StringEncoder(BufType nextBufferType, Charset charset) {
-        if (nextBufferType == null) {
-            throw new NullPointerException("nextBufferType");
-        }
+    public StringEncoder(Charset charset) {
         if (charset == null) {
             throw new NullPointerException("charset");
         }
-        this.nextBufferType = nextBufferType;
         this.charset = charset;
     }
 
     @Override
     public void flush(ChannelHandlerContext ctx, CharSequence msg) throws Exception {
+        if (msg.length() == 0) {
+            return;
+        }
         ByteBuf encoded = Unpooled.copiedBuffer(msg, charset);
-
-        switch (nextBufferType) {
-        case BYTE:
-            ctx.nextOutboundByteBuffer().writeBytes(encoded);
-            break;
-        case MESSAGE:
-            ctx.nextOutboundMessageBuffer().add(encoded);
-            break;
-        default:
-            throw new Error();
+        switch (ctx.nextOutboundBufferType()) {
+            case BYTE:
+                ctx.nextOutboundByteBuffer().writeBytes(encoded);
+                break;
+            case MESSAGE:
+                ctx.nextOutboundMessageBuffer().add(Unpooled.wrappedBuffer(encoded));
+                break;
+            default:
+                throw new Error();
         }
     }
 }