Clean up abstract ChannelHandler impls / Remove ChannelHandlerContext.hasNext*()

- Rename ChannelHandlerAdapter to ChannelDuplexHandler
- Add ChannelHandlerAdapter that implements only ChannelHandler
- Rename CombinedChannelHandler to CombinedChannelDuplexHandler and
  improve runtime validation
- Remove ChannelInbound/OutboundHandlerAdapter which are not useful
- Make ChannelOutboundByteHandlerAdapter similar to
  ChannelInboundByteHandlerAdapter
- Make the tail and head handler of DefaultChannelPipeline accept both
  bytes and messages.  ChannelHandlerContext.hasNext*() were removed
  because they always return true now.
- Removed various unnecessary null checks.
- Correct method/field names:
  inboundBufferSuspended -> channelReadSuspended

buffer/src/main/java/io/netty/buffer/QueueBackedMessageBuf.java

@@ -33,6 +33,9 @@ final class QueueBackedMessageBuf<T> extends AbstractMessageBuf<T> {
 
     @Override
     public boolean offer(T e) {
+        if (e == null) {
+            throw new NullPointerException("e");
+        }
         checkUnfreed();
         return isWritable() && queue.offer(e);
     }

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java

@@ -16,9 +16,12 @@
 package io.netty.handler.codec.http;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.MessageBuf;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.CombinedChannelHandler;
+import io.netty.channel.ChannelInboundByteHandler;
+import io.netty.channel.ChannelOutboundMessageHandler;
+import io.netty.channel.CombinedChannelDuplexHandler;
 import io.netty.handler.codec.PrematureChannelClosureException;
 
 import java.util.ArrayDeque;
@@ -42,13 +45,15 @@ import java.util.concurrent.atomic.AtomicLong;
  * @apiviz.has io.netty.handler.codec.http.HttpResponseDecoder
  * @apiviz.has io.netty.handler.codec.http.HttpRequestEncoder
  */
-public class HttpClientCodec extends CombinedChannelHandler {
+public final class HttpClientCodec
+        extends CombinedChannelDuplexHandler
+        implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<HttpObject> {
 
     /** A queue that is used for correlating a request and a response. */
-    final Queue<HttpMethod> queue = new ArrayDeque<HttpMethod>();
+    private final Queue<HttpMethod> queue = new ArrayDeque<HttpMethod>();
 
     /** If true, decoding stops (i.e. pass-through) */
-    volatile boolean done;
+    private volatile boolean done;
 
     private final AtomicLong requestResponseCounter = new AtomicLong();
     private final boolean failOnMissingResponse;
@@ -65,25 +70,53 @@ public class HttpClientCodec extends CombinedChannelHandler {
     /**
      * Creates a new instance with the specified decoder options.
      */
-    public HttpClientCodec(
+    public HttpClientCodec(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
-            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
         this(maxInitialLineLength, maxHeaderSize, maxChunkSize, false);
     }
 
     public HttpClientCodec(
-            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
+            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean failOnMissingResponse) {
-            boolean failOnMissingResponse) {
+        init(new Decoder(maxInitialLineLength, maxHeaderSize, maxChunkSize), new Encoder());
-
-        init(
-                new Decoder(maxInitialLineLength, maxHeaderSize, maxChunkSize),
-                new Encoder());
         this.failOnMissingResponse = failOnMissingResponse;
     }
 
+    private Decoder decoder() {
+        return (Decoder) stateHandler();
+    }
+
+    private Encoder encoder() {
+        return (Encoder) operationHandler();
+    }
+
+    @Override
+    public ByteBuf newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return decoder().newInboundBuffer(ctx);
+    }
+
+    @Override
+    public void discardInboundReadBytes(ChannelHandlerContext ctx) throws Exception {
+        decoder().discardInboundReadBytes(ctx);
+    }
+
+    @Override
+    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        decoder().freeInboundBuffer(ctx);
+    }
+
+    @Override
+    public MessageBuf<HttpObject> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return encoder().newOutboundBuffer(ctx);
+    }
+
+    @Override
+    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        encoder().freeOutboundBuffer(ctx);
+    }
+
     private final class Encoder extends HttpRequestEncoder {
         @Override
         protected void encode(
-                ChannelHandlerContext ctx, Object msg, ByteBuf out) throws Exception {
+                ChannelHandlerContext ctx, HttpObject msg, ByteBuf out) throws Exception {
             if (msg instanceof HttpRequest && !done) {
                 queue.offer(((HttpRequest) msg).getMethod());
             }

codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectEncoder.java

@@ -39,7 +39,7 @@ import static io.netty.handler.codec.http.HttpConstants.*;
  * implement all abstract methods properly.
  * @apiviz.landmark
  */
-public abstract class HttpObjectEncoder<H extends HttpMessage> extends MessageToByteEncoder<Object> {
+public abstract class HttpObjectEncoder<H extends HttpMessage> extends MessageToByteEncoder<HttpObject> {
 
     private static final int ST_INIT = 0;
     private static final int ST_CONTENT_NON_CHUNK = 1;
@@ -56,17 +56,17 @@ public abstract class HttpObjectEncoder<H extends HttpMessage> extends MessageTo
     }
 
     @Override
-    @SuppressWarnings("unchecked")
+    protected void encode(ChannelHandlerContext ctx, HttpObject msg, ByteBuf out) throws Exception {
-    protected void encode(ChannelHandlerContext ctx, Object msg, ByteBuf out) throws Exception {
         if (msg instanceof HttpMessage) {
             if (state != ST_INIT) {
                 throw new IllegalStateException("unexpected message type: " + msg.getClass().getSimpleName());
             }
 
-            HttpMessage m = (HttpMessage) msg;
+            @SuppressWarnings({ "unchecked", "CastConflictsWithInstanceof" })
+            H m = (H) msg;
 
             // Encode the message.
-            encodeInitialLine(out, (H) m);
+            encodeInitialLine(out, m);
             encodeHeaders(out, m);
             out.writeByte(CR);
             out.writeByte(LF);

codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java

@@ -15,7 +15,12 @@
  */
 package io.netty.handler.codec.http;
 
-import io.netty.channel.CombinedChannelHandler;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.MessageBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundByteHandler;
+import io.netty.channel.ChannelOutboundMessageHandler;
+import io.netty.channel.CombinedChannelDuplexHandler;
 
 
 /**
@@ -26,7 +31,9 @@ import io.netty.channel.CombinedChannelHandler;
  * @apiviz.has io.netty.handler.codec.http.HttpRequestDecoder
  * @apiviz.has io.netty.handler.codec.http.HttpResponseEncoder
  */
-public class HttpServerCodec extends CombinedChannelHandler {
+public final class HttpServerCodec
+        extends CombinedChannelDuplexHandler
+        implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<HttpObject> {
 
     /**
      * Creates a new instance with the default decoder options
@@ -40,10 +47,40 @@ public class HttpServerCodec extends CombinedChannelHandler {
     /**
      * Creates a new instance with the specified decoder options.
      */
-    public HttpServerCodec(
+    public HttpServerCodec(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
-            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
+        super(new HttpRequestDecoder(maxInitialLineLength, maxHeaderSize, maxChunkSize), new HttpResponseEncoder());
-        super(
+    }
-                new HttpRequestDecoder(maxInitialLineLength, maxHeaderSize, maxChunkSize),
+
-                new HttpResponseEncoder());
+    private HttpRequestDecoder decoder() {
+        return (HttpRequestDecoder) stateHandler();
+    }
+
+    private HttpResponseEncoder encoder() {
+        return (HttpResponseEncoder) operationHandler();
+    }
+
+    @Override
+    public ByteBuf newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return decoder().newInboundBuffer(ctx);
+    }
+
+    @Override
+    public void discardInboundReadBytes(ChannelHandlerContext ctx) throws Exception {
+        decoder().discardInboundReadBytes(ctx);
+    }
+
+    @Override
+    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        decoder().freeInboundBuffer(ctx);
+    }
+
+    @Override
+    public MessageBuf<HttpObject> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return encoder().newOutboundBuffer(ctx);
+    }
+
+    @Override
+    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        encoder().freeOutboundBuffer(ctx);
     }
 }

codec-http/src/main/java/io/netty/handler/codec/http/package-info.java

@@ -18,7 +18,6 @@
  * Encoder, decoder and their related message types for HTTP.
  *
  * @apiviz.exclude ^java\.lang\.
- * @apiviz.exclude OneToOne(Encoder|Decoder)$
  * @apiviz.exclude \.HttpHeaders\.
  * @apiviz.exclude \.codec\.replay\.
  * @apiviz.exclude \.(Simple)?Channel[A-Za-z]*Handler$

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyFrameCodec.java

@@ -15,7 +15,12 @@
  */
 package io.netty.handler.codec.spdy;
 
-import io.netty.channel.CombinedChannelHandler;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.MessageBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundByteHandler;
+import io.netty.channel.ChannelOutboundMessageHandler;
+import io.netty.channel.CombinedChannelDuplexHandler;
 
 
 /**
@@ -24,7 +29,9 @@ import io.netty.channel.CombinedChannelHandler;
  * @apiviz.has io.netty.handler.codec.spdy.SpdyFrameDecoder
  * @apiviz.has io.netty.handler.codec.spdy.SpdyFrameEncoder
  */
-public class SpdyFrameCodec extends CombinedChannelHandler {
+public final class SpdyFrameCodec
+        extends CombinedChannelDuplexHandler
+        implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<Object> {
 
     /**
      * Creates a new instance with the specified {@code version} and
@@ -47,4 +54,37 @@ public class SpdyFrameCodec extends CombinedChannelHandler {
                 new SpdyFrameDecoder(version, maxChunkSize, maxHeaderSize),
                 new SpdyFrameEncoder(version, compressionLevel, windowBits, memLevel));
     }
+
+    private SpdyFrameDecoder decoder() {
+        return (SpdyFrameDecoder) stateHandler();
+    }
+
+    private SpdyFrameEncoder encoder() {
+        return (SpdyFrameEncoder) operationHandler();
+    }
+
+    @Override
+    public ByteBuf newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return decoder().newInboundBuffer(ctx);
+    }
+
+    @Override
+    public void discardInboundReadBytes(ChannelHandlerContext ctx) throws Exception {
+        decoder().discardInboundReadBytes(ctx);
+    }
+
+    @Override
+    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        decoder().freeInboundBuffer(ctx);
+    }
+
+    @Override
+    public MessageBuf<Object> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return encoder().newOutboundBuffer(ctx);
+    }
+
+    @Override
+    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        encoder().freeOutboundBuffer(ctx);
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyHttpCodec.java

@@ -15,7 +15,12 @@
  */
 package io.netty.handler.codec.spdy;
 
-import io.netty.channel.CombinedChannelHandler;
+import io.netty.buffer.MessageBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundMessageHandler;
+import io.netty.channel.ChannelOutboundMessageHandler;
+import io.netty.channel.CombinedChannelDuplexHandler;
+import io.netty.handler.codec.http.HttpObject;
 
 
 /**
@@ -23,14 +28,42 @@ import io.netty.channel.CombinedChannelHandler;
  * @apiviz.has io.netty.handler.codec.sdpy.SpdyHttpDecoder
  * @apiviz.has io.netty.handler.codec.spdy.SpdyHttpEncoder
  */
-public class SpdyHttpCodec extends CombinedChannelHandler {
+public final class SpdyHttpCodec
+        extends CombinedChannelDuplexHandler
+        implements ChannelInboundMessageHandler<Object>, ChannelOutboundMessageHandler<HttpObject> {
 
     /**
      * Creates a new instance with the specified decoder options.
      */
     public SpdyHttpCodec(int version, int maxContentLength) {
-        super(
+        super(new SpdyHttpDecoder(version, maxContentLength), new SpdyHttpEncoder(version));
-                new SpdyHttpDecoder(version, maxContentLength),
+    }
-                new SpdyHttpEncoder(version));
+
+    private SpdyHttpDecoder decoder() {
+        return (SpdyHttpDecoder) stateHandler();
+    }
+
+    private SpdyHttpEncoder encoder() {
+        return (SpdyHttpEncoder) operationHandler();
+    }
+
+    @Override
+    public MessageBuf<Object> newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return decoder().newInboundBuffer(ctx);
+    }
+
+    @Override
+    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        decoder().freeInboundBuffer(ctx);
+    }
+
+    @Override
+    public MessageBuf<HttpObject> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        return encoder().newOutboundBuffer(ctx);
+    }
+
+    @Override
+    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        encoder().freeOutboundBuffer(ctx);
     }
 }

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyHttpEncoder.java

@@ -120,7 +120,7 @@ import java.util.Map;
  * All pushed resources should be sent before sending the response
  * that corresponds to the initial request.
  */
-public class SpdyHttpEncoder extends MessageToMessageEncoder<Object> {
+public class SpdyHttpEncoder extends MessageToMessageEncoder<HttpObject> {
 
     private final int spdyVersion;
     private volatile int currentStreamId;
@@ -141,7 +141,7 @@ public class SpdyHttpEncoder extends MessageToMessageEncoder<Object> {
     }
 
     @Override
-    public Object encode(ChannelHandlerContext ctx, Object msg) throws Exception {
+    public Object encode(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
 
         List<Object> out = new ArrayList<Object>();
         if (msg instanceof HttpRequest) {
@@ -288,7 +288,7 @@ public class SpdyHttpEncoder extends MessageToMessageEncoder<Object> {
     }
 
     @Override
-    protected void freeOutboundMessage(Object msg) throws Exception {
+    protected void freeOutboundMessage(HttpObject msg) throws Exception {
         if (msg instanceof HttpContent) {
             // Will be freed later as the content of them is just reused here
             return;

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyOrHttpChooser.java

@@ -16,8 +16,8 @@
 package io.netty.handler.codec.spdy;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelInboundMessageHandler;
@@ -35,7 +35,7 @@ import javax.net.ssl.SSLEngine;
  * much about the low-level details.
  *
  */
-public abstract class SpdyOrHttpChooser extends ChannelHandlerAdapter implements ChannelInboundByteHandler {
+public abstract class SpdyOrHttpChooser extends ChannelDuplexHandler implements ChannelInboundByteHandler {
 
     public enum SelectedProtocol {
         SpdyVersion2,

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdySessionHandler.java

@@ -17,9 +17,9 @@ package io.netty.handler.codec.spdy;
 
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundMessageHandler;
 import io.netty.channel.ChannelOutboundMessageHandler;
@@ -31,7 +31,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  * Manages streams within a SPDY session.
  */
 public class SpdySessionHandler
-        extends ChannelHandlerAdapter
+        extends ChannelDuplexHandler
         implements ChannelInboundMessageHandler<Object>, ChannelOutboundMessageHandler<Object> {
 
     private static final SpdyProtocolException PROTOCOL_EXCEPTION = new SpdyProtocolException();

codec/src/main/java/io/netty/handler/codec/ByteToByteCodec.java

@@ -16,7 +16,7 @@
 package io.netty.handler.codec;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelOutboundByteHandler;
@@ -53,7 +53,7 @@ import io.netty.channel.ChannelPromise;
  * </pre>
  */
 public abstract class ByteToByteCodec
-        extends ChannelHandlerAdapter
+        extends ChannelDuplexHandler
         implements ChannelInboundByteHandler, ChannelOutboundByteHandler {
 
     private final ByteToByteEncoder encoder = new ByteToByteEncoder() {

codec/src/main/java/io/netty/handler/codec/ByteToByteEncoder.java

@@ -47,8 +47,7 @@ import io.netty.channel.PartialFlushException;
 public abstract class ByteToByteEncoder extends ChannelOutboundByteHandlerAdapter {
 
     @Override
-    public void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+    protected void flush(ChannelHandlerContext ctx, ByteBuf in, ChannelPromise promise) throws Exception {
-        ByteBuf in = ctx.outboundByteBuffer();
         ByteBuf out = ctx.nextOutboundByteBuffer();
         boolean encoded = false;
 

codec/src/main/java/io/netty/handler/codec/ByteToMessageCodec.java

@@ -17,14 +17,14 @@ package io.netty.handler.codec;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.MessageBuf;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelHandlerUtil;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelOutboundMessageHandler;
 import io.netty.channel.ChannelPromise;
 
-public abstract class ByteToMessageCodec<I> extends ChannelHandlerAdapter
+public abstract class ByteToMessageCodec<I> extends ChannelDuplexHandler
         implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<I> {
 
     private final Class<?>[] encodableMessageTypes;

codec/src/main/java/io/netty/handler/codec/MessageToMessageCodec.java

@@ -16,7 +16,7 @@
 package io.netty.handler.codec;
 
 import io.netty.buffer.MessageBuf;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelHandlerUtil;
 import io.netty.channel.ChannelInboundMessageHandler;
@@ -49,7 +49,7 @@ import io.netty.channel.ChannelPromise;
  * </pre>
  */
 public abstract class MessageToMessageCodec<INBOUND_IN, OUTBOUND_IN>
-        extends ChannelHandlerAdapter
+        extends ChannelDuplexHandler
         implements ChannelInboundMessageHandler<INBOUND_IN>,
                    ChannelOutboundMessageHandler<OUTBOUND_IN> {
 

codec/src/main/java/io/netty/handler/codec/MessageToMessageDecoder.java

@@ -67,6 +67,7 @@ public abstract class MessageToMessageDecoder<I>
     public void inboundBufferUpdated(ChannelHandlerContext ctx)
             throws Exception {
         MessageBuf<I> in = ctx.inboundMessageBuffer();
+        MessageBuf<Object> out = ctx.nextInboundMessageBuffer();
         boolean notify = false;
         for (;;) {
             try {
@@ -75,7 +76,7 @@ public abstract class MessageToMessageDecoder<I>
                     break;
                 }
                 if (!isDecodable(msg)) {
-                    ChannelHandlerUtil.addToNextInboundBuffer(ctx, msg);
+                    out.add(msg);
                     notify = true;
                     continue;
                 }

handler/src/main/java/io/netty/handler/logging/LoggingHandler.java

@@ -15,9 +15,9 @@
  */
 package io.netty.handler.logging;
 
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandler.Sharable;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
 import io.netty.logging.InternalLogLevel;
@@ -32,7 +32,7 @@ import java.net.SocketAddress;
  * @apiviz.landmark
  */
 @Sharable
-public class LoggingHandler extends ChannelHandlerAdapter {
+public class LoggingHandler extends ChannelDuplexHandler {
 
     private static final LogLevel DEFAULT_LEVEL = LogLevel.DEBUG;
 

handler/src/main/java/io/netty/handler/ssl/SslHandler.java

@@ -18,10 +18,10 @@ package io.netty.handler.ssl;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelFlushPromiseNotifier;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelOutboundByteHandler;
@@ -142,7 +142,7 @@ import java.util.regex.Pattern;
  * @apiviz.uses io.netty.handler.ssl.SslBufferPool
  */
 public class SslHandler
-        extends ChannelHandlerAdapter
+        extends ChannelDuplexHandler
         implements ChannelInboundByteHandler, ChannelOutboundByteHandler {
 
     private static final InternalLogger logger =

handler/src/main/java/io/netty/handler/stream/ChunkedWriteHandler.java

@@ -18,11 +18,11 @@ package io.netty.handler.stream;
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelException;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOutboundMessageHandler;
 import io.netty.channel.ChannelPipeline;
@@ -67,7 +67,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  * @apiviz.has io.netty.handler.stream.ChunkedInput oneway - - reads from
  */
 public class ChunkedWriteHandler
-        extends ChannelHandlerAdapter implements ChannelOutboundMessageHandler<Object> {
+        extends ChannelDuplexHandler implements ChannelOutboundMessageHandler<Object> {
 
     private static final InternalLogger logger =
         InternalLoggerFactory.getInstance(ChunkedWriteHandler.class);

handler/src/main/java/io/netty/handler/timeout/IdleStateHandler.java

@@ -17,9 +17,9 @@ package io.netty.handler.timeout;
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOperationHandler;
@@ -75,7 +75,7 @@ import java.util.concurrent.TimeUnit;
  * }
  *
  * // Handler should handle the {@link IdleStateEvent} triggered by {@link IdleStateHandler}.
- * public class MyHandler extends {@link ChannelHandlerAdapter} {
+ * public class MyHandler extends {@link ChannelDuplexHandler} {
  *     {@code @Override}
  *     public void userEventTriggered({@link ChannelHandlerContext} ctx, {@link Object} evt) throws {@link Exception} {
  *         if (evt instanceof {@link IdleState}} {

handler/src/main/java/io/netty/handler/timeout/ReadTimeoutHandler.java

@@ -17,7 +17,7 @@ package io.netty.handler.timeout;
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelStateHandlerAdapter;
@@ -41,7 +41,7 @@ import java.util.concurrent.TimeUnit;
  * }
  *
  * // Handler should handle the {@link ReadTimeoutException}.
- * public class MyHandler extends {@link ChannelHandlerAdapter} {
+ * public class MyHandler extends {@link ChannelDuplexHandler} {
  *     {@code @Override}
  *     public void exceptionCaught({@link ChannelHandlerContext} ctx, {@link Throwable} cause)
  *             throws {@link Exception} {

handler/src/main/java/io/netty/handler/timeout/WriteTimeoutHandler.java

@@ -17,9 +17,9 @@ package io.netty.handler.timeout;
 
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOperationHandlerAdapter;
@@ -45,7 +45,7 @@ import java.util.concurrent.TimeUnit;
  * }
  *
  * // Handler should handle the {@link WriteTimeoutException}.
- * public class MyHandler extends {@link ChannelHandlerAdapter} {
+ * public class MyHandler extends {@link ChannelDuplexHandler} {
  *     {@code @Override}
  *     public void exceptionCaught({@link ChannelHandlerContext} ctx, {@link Throwable} cause)
  *             throws {@link Exception} {

handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java

@@ -16,7 +16,7 @@
 package io.netty.handler.traffic;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelOutboundByteHandler;
@@ -43,7 +43,7 @@ import java.util.concurrent.TimeUnit;
  * or start the monitoring, to change the checkInterval directly, or to have access to its values.</li>
  * </ul>
  */
-public abstract class AbstractTrafficShapingHandler extends ChannelHandlerAdapter
+public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler
         implements ChannelInboundByteHandler, ChannelOutboundByteHandler {
 
     /**

transport-sctp/src/main/java/io/netty/handler/codec/sctp/SctpOutboundByteStreamHandler.java

@@ -43,9 +43,7 @@ public class SctpOutboundByteStreamHandler extends ChannelOutboundByteHandlerAda
     }
 
     @Override
-    public void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+    protected void flush(ChannelHandlerContext ctx, ByteBuf in, ChannelPromise promise) throws Exception {
-        ByteBuf in = ctx.outboundByteBuffer();
-
         try {
             MessageBuf<Object> out = ctx.nextOutboundMessageBuffer();
             ByteBuf payload = Unpooled.buffer(in.readableBytes());

transport/src/main/java/io/netty/channel/AbstractChannel.java

@@ -15,6 +15,7 @@
  */
 package io.netty.channel;
 
+import io.netty.buffer.BufType;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.MessageBuf;
@@ -822,7 +823,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
         private int outboundBufSize() {
             final int bufSize;
             final ChannelHandlerContext ctx = directOutboundContext();
-            if (ctx.hasOutboundByteBuffer()) {
+            if (metadata().bufferType() == BufType.BYTE) {
                 bufSize = ctx.outboundByteBuffer().readableBytes();
             } else {
                 bufSize = ctx.outboundMessageBuffer().size();
@@ -869,7 +870,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             ChannelHandlerContext ctx = directOutboundContext();
             Throwable cause = null;
             try {
-                if (ctx.hasOutboundByteBuffer()) {
+                if (metadata().bufferType() == BufType.BYTE) {
                     ByteBuf out = ctx.outboundByteBuffer();
                     int oldSize = out.readableBytes();
                     try {
@@ -877,7 +878,9 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                     } catch (Throwable t) {
                         cause = t;
                     } finally {
-                        flushFutureNotifier.increaseWriteCounter(oldSize - out.readableBytes());
+                        int delta = oldSize - out.readableBytes();
+                        out.discardSomeReadBytes();
+                        flushFutureNotifier.increaseWriteCounter(delta);
                     }
                 } else {
                     MessageBuf<Object> out = ctx.outboundMessageBuffer();

transport/src/main/java/io/netty/channel/ChannelDuplexHandler.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel;
+
+import java.net.SocketAddress;
+
+/**
+ * {@link ChannelHandler} implementation which represents a combination out of a {@link ChannelStateHandler} and
+ * the {@link ChannelOperationHandler}.
+ *
+ * It is a good starting point if your {@link ChannelHandler} implementation needs to intercept operations and also
+ * state updates.
+ */
+public abstract class ChannelDuplexHandler extends ChannelStateHandlerAdapter implements ChannelOperationHandler {
+
+    /**
+     * Calls {@link ChannelHandlerContext#bind(SocketAddress, ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void bind(ChannelHandlerContext ctx, SocketAddress localAddress,
+                     ChannelPromise future) throws Exception {
+        ctx.bind(localAddress, future);
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#connect(SocketAddress, SocketAddress, ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress,
+                        SocketAddress localAddress, ChannelPromise future) throws Exception {
+        ctx.connect(remoteAddress, localAddress, future);
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#disconnect(ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void disconnect(ChannelHandlerContext ctx, ChannelPromise future)
+            throws Exception {
+        ctx.disconnect(future);
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#close(ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void close(ChannelHandlerContext ctx, ChannelPromise future)
+            throws Exception {
+        ctx.close(future);
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#close(ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void deregister(ChannelHandlerContext ctx, ChannelPromise future)
+            throws Exception {
+        ctx.deregister(future);
+    }
+
+    @Override
+    public void read(ChannelHandlerContext ctx) {
+        ctx.read();
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#flush(ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     *
+     * Be aware that if your class also implement {@link ChannelOutboundHandler} it need to {@code @Override} this
+     * method and provide some proper implementation. Fail to do so, will result in an {@link IllegalStateException}!
+     */
+    @Override
+    public void flush(ChannelHandlerContext ctx, ChannelPromise future)
+            throws Exception {
+        if (this instanceof ChannelOutboundHandler) {
+            throw new IllegalStateException(
+                    "flush(...) must be overridden by " + getClass().getName() +
+                            ", which implements " + ChannelOutboundHandler.class.getSimpleName());
+        }
+        ctx.flush(future);
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#sendFile(FileRegion, ChannelPromise)} to forward
+     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     *
+     * Sub-classes may override this method to change behavior.
+     */
+    @Override
+    public void sendFile(ChannelHandlerContext ctx, FileRegion region, ChannelPromise future) throws Exception {
+        ctx.sendFile(region, future);
+    }
+}

transport/src/main/java/io/netty/channel/ChannelHandlerAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 The Netty Project
+ * Copyright 2013 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -13,112 +13,75 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
+
 package io.netty.channel;
 
-import java.net.SocketAddress;
+public abstract class ChannelHandlerAdapter implements ChannelHandler {
+
+    // Not using volatile because it's used only for a sanity check.
+    boolean added;
 
     /**
- * {@link ChannelHandler} implementation which represents a combination out of a {@link ChannelStateHandler} and
+     * Return {@code true} if the implementation is {@link Sharable} and so can be added
- * the {@link ChannelOperationHandler}.
+     * to different {@link ChannelPipeline}s.
- *
- * It is a good starting point if your {@link ChannelHandler} implementation needs to intercept operations and also
- * state updates.
      */
-public abstract class ChannelHandlerAdapter extends ChannelStateHandlerAdapter implements ChannelOperationHandler {
+    final boolean isSharable() {
-
+        return getClass().isAnnotationPresent(Sharable.class);
-    /**
-     * Calls {@link ChannelHandlerContext#bind(SocketAddress, ChannelPromise)} to forward
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void bind(ChannelHandlerContext ctx, SocketAddress localAddress,
-                     ChannelPromise future) throws Exception {
-        ctx.bind(localAddress, future);
     }
 
     /**
-     * Calls {@link ChannelHandlerContext#connect(SocketAddress, SocketAddress, ChannelPromise)} to forward
+     * Do nothing by default, sub-classes may override this method.
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
      */
     @Override
-    public void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress,
+    public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
-                        SocketAddress localAddress, ChannelPromise future) throws Exception {
+        // NOOP
-        ctx.connect(remoteAddress, localAddress, future);
     }
 
     /**
-     * Calls {@link ChannelHandlerContext#disconnect(ChannelPromise)} to forward
+     * Do nothing by default, sub-classes may override this method.
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     */
+    @Override
+    public void afterAdd(ChannelHandlerContext ctx) throws Exception {
+        // NOOP
+    }
+
+    /**
+     * Do nothing by default, sub-classes may override this method.
+     */
+    @Override
+    public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
+        // NOOP
+    }
+
+    /**
+     * Do nothing by default, sub-classes may override this method.
+     */
+    @Override
+    public void afterRemove(ChannelHandlerContext ctx) throws Exception {
+        // NOOP
+    }
+
+    /**
+     * Calls {@link ChannelHandlerContext#fireExceptionCaught(Throwable)} to forward
+     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
      *
      * Sub-classes may override this method to change behavior.
      */
     @Override
-    public void disconnect(ChannelHandlerContext ctx, ChannelPromise future)
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
             throws Exception {
-        ctx.disconnect(future);
+        ctx.fireExceptionCaught(cause);
     }
 
     /**
-     * Calls {@link ChannelHandlerContext#close(ChannelPromise)} to forward
+     * Calls {@link ChannelHandlerContext#fireUserEventTriggered(Object)} to forward
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
+     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
      *
      * Sub-classes may override this method to change behavior.
      */
     @Override
-    public void close(ChannelHandlerContext ctx, ChannelPromise future)
+    public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
             throws Exception {
-        ctx.close(future);
+        ctx.fireUserEventTriggered(evt);
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#close(ChannelPromise)} to forward
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void deregister(ChannelHandlerContext ctx, ChannelPromise future)
-            throws Exception {
-        ctx.deregister(future);
-    }
-
-    @Override
-    public void read(ChannelHandlerContext ctx) {
-        ctx.read();
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#flush(ChannelPromise)} to forward
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     *
-     * Be aware that if your class also implement {@link ChannelOutboundHandler} it need to {@code @Override} this
-     * method and provide some proper implementation. Fail to do so, will result in an {@link IllegalStateException}!
-     */
-    @Override
-    public void flush(ChannelHandlerContext ctx, ChannelPromise future)
-            throws Exception {
-        if (this instanceof ChannelOutboundHandler) {
-            throw new IllegalStateException(
-                    "flush(...) must be overridden by " + getClass().getName() +
-                            ", which implements " + ChannelOutboundHandler.class.getSimpleName());
-        }
-        ctx.flush(future);
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#sendFile(FileRegion, ChannelPromise)} to forward
-     * to the next {@link ChannelOperationHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void sendFile(ChannelHandlerContext ctx, FileRegion region, ChannelPromise future) throws Exception {
-        ctx.sendFile(region, future);
     }
 }

transport/src/main/java/io/netty/channel/ChannelHandlerContext.java

@@ -47,7 +47,7 @@ import java.util.Set;
  * You can keep the {@link ChannelHandlerContext} for later use, such as
  * triggering an event outside the handler methods, even from a different thread.
  * <pre>
- * public class MyHandler extends {@link ChannelHandlerAdapter} {
+ * public class MyHandler extends {@link ChannelDuplexHandler} {
  *
  *     <b>private {@link ChannelHandlerContext} ctx;</b>
  *
@@ -293,52 +293,22 @@ public interface ChannelHandlerContext
     <T> MessageBuf<T> replaceOutboundMessageBuffer(MessageBuf<T> newOutboundMsgBuf);
 
     /**
-     * Return {@code true} if the next {@link ChannelHandlerContext} has a {@link ByteBuf} for handling
+     * Return the {@link ByteBuf} of the next {@link ChannelHandlerContext}.
-     * inbound data.
-     */
-    boolean hasNextInboundByteBuffer();
-
-    /**
-     * Return {@code true} if the next {@link ChannelHandlerContext} has a {@link MessageBuf} for handling
-     * inbound data.
-     */
-    boolean hasNextInboundMessageBuffer();
-
-    /**
-     * Return the {@link ByteBuf} of the next {@link ChannelHandlerContext} if {@link #hasNextInboundByteBuffer()}
-     * returned {@code true}, otherwise a {@link UnsupportedOperationException} is thrown.
      */
     ByteBuf nextInboundByteBuffer();
 
     /**
-     * Return the {@link MessageBuf} of the next {@link ChannelHandlerContext} if
+     * Return the {@link MessageBuf} of the next {@link ChannelHandlerContext}.
-     * {@link #hasNextInboundMessageBuffer()} returned {@code true}, otherwise a
-     * {@link UnsupportedOperationException} is thrown.
      */
     MessageBuf<Object> nextInboundMessageBuffer();
 
     /**
-     * Return {@code true} if the next {@link ChannelHandlerContext} has a {@link ByteBuf} for handling outbound
+     * Return the {@link ByteBuf} of the next {@link ChannelHandlerContext}.
-     * data.
-     */
-    boolean hasNextOutboundByteBuffer();
-
-    /**
-     * Return {@code true} if the next {@link ChannelHandlerContext} has a {@link MessageBuf} for handling
-     * outbound data.
-     */
-    boolean hasNextOutboundMessageBuffer();
-
-    /**
-     * Return the {@link ByteBuf} of the next {@link ChannelHandlerContext} if {@link #hasNextOutboundByteBuffer()}
-     * returned {@code true}, otherwise a {@link UnsupportedOperationException} is thrown.
      */
     ByteBuf nextOutboundByteBuffer();
 
     /**
-     * Return the {@link MessageBuf} of the next {@link ChannelHandlerContext} if
+     * Return the {@link MessageBuf} of the next {@link ChannelHandlerContext}.
-     * {@link #hasNextOutboundMessageBuffer()} returned {@code true}, otherwise a
-     * {@link UnsupportedOperationException} is thrown.
      */
     MessageBuf<Object> nextOutboundMessageBuffer();
 }

transport/src/main/java/io/netty/channel/ChannelHandlerUtil.java

@@ -64,39 +64,14 @@ public final class ChannelHandlerUtil {
         }
 
         if (inbound) {
-            if (ctx.hasNextInboundMessageBuffer()) {
             ctx.nextInboundMessageBuffer().add(msg);
             return true;
         }
 
-            if (msg instanceof ByteBuf && ctx.hasNextInboundByteBuffer()) {
-                ByteBuf altDst = ctx.nextInboundByteBuffer();
-                ByteBuf src = (ByteBuf) msg;
-                altDst.writeBytes(src, src.readerIndex(), src.readableBytes());
-                return true;
-            }
-        } else {
-            if (ctx.hasNextOutboundMessageBuffer()) {
         ctx.nextOutboundMessageBuffer().add(msg);
         return true;
     }
 
-            if (msg instanceof ByteBuf && ctx.hasNextOutboundByteBuffer()) {
-                ByteBuf altDst = ctx.nextOutboundByteBuffer();
-                ByteBuf src = (ByteBuf) msg;
-                altDst.writeBytes(src, src.readerIndex(), src.readableBytes());
-                return true;
-            }
-        }
-
-        throw new NoSuchBufferException(String.format(
-                "the handler '%s' could not find a %s which accepts a %s.",
-                ctx.name(),
-                inbound? ChannelInboundHandler.class.getSimpleName()
-                       : ChannelOutboundHandler.class.getSimpleName(),
-                msg.getClass().getSimpleName()));
-    }
-
     private static final Class<?>[] EMPTY_TYPES = new Class<?>[0];
 
     /**

transport/src/main/java/io/netty/channel/ChannelInboundByteHandlerAdapter.java

@@ -19,13 +19,13 @@ import io.netty.buffer.ByteBuf;
 
 
 /**
- * Abstract base class for {@link ChannelInboundHandlerAdapter} which should be extended by the user to
+ * Abstract base class for {@link ChannelInboundByteHandler} which should be extended by the user to
  * get notified once more data is ready to get consumed from the inbound {@link ByteBuf}.
  *
  * This implementation is a good starting point for most users.
  */
 public abstract class ChannelInboundByteHandlerAdapter
-        extends ChannelInboundHandlerAdapter implements ChannelInboundByteHandler {
+        extends ChannelStateHandlerAdapter implements ChannelInboundByteHandler {
 
     /**
      * Create a new unpooled {@link ByteBuf} by default. Sub-classes may override this to offer a more

transport/src/main/java/io/netty/channel/ChannelInboundHandlerAdapter.java

@@ -1,43 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.channel;
-
-
-import io.netty.buffer.Buf;
-
-/**
- * Abstract base class for a {@link ChannelHandler} that handles inbound data.
- *
- * Please either extend {@link ChannelInboundByteHandlerAdapter} or
- * {@link ChannelInboundMessageHandlerAdapter}.
- */
-abstract class ChannelInboundHandlerAdapter
-        extends ChannelStateHandlerAdapter implements ChannelInboundHandler {
-
-    /**
-     * Calls {@link Buf#free()} to free the buffer, sub-classes may override this.
-     *
-     * When doing so be aware that you will need to handle all the resource management by your own.
-     */
-    @Override
-    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        if (ctx.hasInboundByteBuffer()) {
-            ctx.inboundByteBuffer().free();
-        } else {
-            ctx.inboundMessageBuffer().free();
-        }
-    }
-}

transport/src/main/java/io/netty/channel/ChannelInboundInvoker.java

@@ -85,8 +85,8 @@ public interface ChannelInboundInvoker {
     void fireInboundBufferUpdated();
 
     /**
-     * Triggers an {@link ChannelStateHandler#channelReadSuspended(ChannelHandlerContext) inboundBufferSuspended}
+     * Triggers an {@link ChannelStateHandler#channelReadSuspended(ChannelHandlerContext) channelReadSuspended}
      * event to the next {@link ChannelStateHandler} in the {@link ChannelPipeline}.
      */
-    void fireInboundBufferSuspended();
+    void fireChannelReadSuspended();
 }

transport/src/main/java/io/netty/channel/ChannelInboundMessageHandlerAdapter.java

@@ -41,7 +41,7 @@ import io.netty.buffer.Unpooled;
  * @param <I>   The type of the messages to handle
  */
 public abstract class ChannelInboundMessageHandlerAdapter<I>
-        extends ChannelInboundHandlerAdapter implements ChannelInboundMessageHandler<I> {
+        extends ChannelStateHandlerAdapter implements ChannelInboundMessageHandler<I> {
 
     private final Class<?>[] acceptedMsgTypes;
 
@@ -73,6 +73,7 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
 
         try {
             MessageBuf<I> in = ctx.inboundMessageBuffer();
+            MessageBuf<Object> out = null;
             for (;;) {
                 Object msg = in.poll();
                 if (msg == null) {
@@ -80,7 +81,10 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
                 }
                 try {
                     if (!isSupported(msg)) {
-                        ChannelHandlerUtil.addToNextInboundBuffer(ctx, msg);
+                        if (out == null) {
+                            out = ctx.nextOutboundMessageBuffer();
+                        }
+                        out.add(msg);
                         unsupportedFound = true;
                         continue;
                     }

transport/src/main/java/io/netty/channel/ChannelOperationHandlerAdapter.java

@@ -17,63 +17,7 @@ package io.netty.channel;
 
 import java.net.SocketAddress;
 
-public abstract class ChannelOperationHandlerAdapter implements ChannelOperationHandler {
+public abstract class ChannelOperationHandlerAdapter extends ChannelHandlerAdapter implements ChannelOperationHandler {
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void afterAdd(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void afterRemove(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#fireExceptionCaught(Throwable)} to forward
-     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
-            throws Exception {
-        ctx.fireExceptionCaught(cause);
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#fireUserEventTriggered(Object)} to forward
-     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
-            throws Exception {
-        ctx.fireUserEventTriggered(evt);
-    }
 
     /**
      * Calls {@link ChannelHandlerContext#bind(SocketAddress, ChannelPromise)} to forward

transport/src/main/java/io/netty/channel/ChannelOutboundByteHandlerAdapter.java

@@ -21,7 +21,7 @@ import io.netty.buffer.ByteBuf;
  * Abstract base class which handles outgoing bytes.
  */
 public abstract class ChannelOutboundByteHandlerAdapter
-        extends ChannelOutboundHandlerAdapter implements ChannelOutboundByteHandler {
+        extends ChannelOperationHandlerAdapter implements ChannelOutboundByteHandler {
     @Override
     public ByteBuf newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
         return ctx.alloc().buffer();
@@ -36,4 +36,21 @@ public abstract class ChannelOutboundByteHandlerAdapter
     public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
         ctx.outboundByteBuffer().free();
     }
+
+    /**
+     * This method merely delegates the flush request to {@link #flush(ChannelHandlerContext, ByteBuf, ChannelPromise)}.
+     */
+    @Override
+    public final void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+        flush(ctx, ctx.outboundByteBuffer(), promise);
+    }
+
+    /**
+     * Invoked when a flush request has been issued.
+     *
+     * @param ctx the current context
+     * @param in this handler's outbound buffer
+     * @param promise the promise associate with the current flush request
+     */
+    protected abstract void flush(ChannelHandlerContext ctx, ByteBuf in, ChannelPromise promise) throws Exception;
 }

transport/src/main/java/io/netty/channel/ChannelOutboundHandlerAdapter.java

@@ -1,43 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.channel;
-
-import io.netty.buffer.Buf;
-
-
-/**
- * Abstract base class for a {@link ChannelHandler} that handles outbound data.
- *
- * Please extend {@link ChannelOutboundByteHandlerAdapter} or
- * {@link ChannelOutboundMessageHandlerAdapter}.
- */
-abstract class ChannelOutboundHandlerAdapter
-        extends ChannelOperationHandlerAdapter implements ChannelOutboundHandler {
-
-    /**
-     * Calls {@link Buf#free()} to free the buffer, sub-classes may override this.
-     *
-     * When doing so be aware that you will need to handle all the resource management by your own.
-     */
-    @Override
-    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        if (ctx.hasOutboundByteBuffer()) {
-            ctx.outboundByteBuffer().free();
-        } else {
-            ctx.outboundMessageBuffer().free();
-        }
-    }
-}

transport/src/main/java/io/netty/channel/ChannelOutboundInvoker.java

@@ -157,7 +157,7 @@ public interface ChannelOutboundInvoker {
      * Reads data from the {@link Channel} into the first inbound buffer, triggers an
      * {@link ChannelStateHandler#inboundBufferUpdated(ChannelHandlerContext) inboundBufferUpdated} event if data was
      * read, and triggers an
-     * {@link ChannelStateHandler#channelReadSuspended(ChannelHandlerContext) inboundBufferSuspended} event so the
+     * {@link ChannelStateHandler#channelReadSuspended(ChannelHandlerContext) channelReadSuspended} event so the
      * handler can decide to continue reading.  If there's a pending read operation already, this method does nothing.
      */
     void read();

transport/src/main/java/io/netty/channel/ChannelOutboundMessageHandlerAdapter.java

@@ -24,7 +24,7 @@ import io.netty.buffer.Unpooled;
  * @param <I>   The type of the messages to handle
  */
 public abstract class ChannelOutboundMessageHandlerAdapter<I>
-        extends ChannelOutboundHandlerAdapter implements ChannelOutboundMessageHandler<I> {
+        extends ChannelOperationHandlerAdapter implements ChannelOutboundMessageHandler<I> {
 
     @Override
     public MessageBuf<I> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {

transport/src/main/java/io/netty/channel/ChannelStateHandlerAdapter.java

@@ -23,73 +23,7 @@ package io.netty.channel;
  * This implementation just forward the operation to the next {@link ChannelHandler} in the
  * {@link ChannelPipeline}. Sub-classes may override a method implementation to change this.
  */
-public class ChannelStateHandlerAdapter implements ChannelStateHandler {
+public abstract class ChannelStateHandlerAdapter extends ChannelHandlerAdapter implements ChannelStateHandler {
-
-    // Not using volatile because it's used only for a sanity check.
-    boolean added;
-
-    /**
-     * Return {@code true} if the implementation is {@link Sharable} and so can be added
-     * to different {@link ChannelPipeline}s.
-     */
-    final boolean isSharable() {
-        return getClass().isAnnotationPresent(Sharable.class);
-    }
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void afterAdd(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Do nothing by default, sub-classes may override this method.
-     */
-    @Override
-    public void afterRemove(ChannelHandlerContext ctx) throws Exception {
-        // NOOP
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#fireExceptionCaught(Throwable)} to forward
-     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
-            throws Exception {
-        ctx.fireExceptionCaught(cause);
-    }
-
-    /**
-     * Calls {@link ChannelHandlerContext#fireUserEventTriggered(Object)} to forward
-     * to the next {@link ChannelHandler} in the {@link ChannelPipeline}.
-     *
-     * Sub-classes may override this method to change behavior.
-     */
-    @Override
-    public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
-            throws Exception {
-        ctx.fireUserEventTriggered(evt);
-    }
 
     /**
      * Calls {@link ChannelHandlerContext#fireChannelRegistered()} to forward
@@ -156,6 +90,6 @@ public class ChannelStateHandlerAdapter implements ChannelStateHandler {
 
     @Override
     public void channelReadSuspended(ChannelHandlerContext ctx) throws Exception {
-        ctx.fireInboundBufferSuspended();
+        ctx.fireChannelReadSuspended();
     }
 }

transport/src/main/java/io/netty/channel/CombinedChannelDuplexHandler.java

@@ -0,0 +1,244 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel;
+
+import java.net.SocketAddress;
+
+/**
+ *  Combines a {@link ChannelStateHandler} and a {@link ChannelOperationHandler} into one {@link ChannelHandler}.
+ *
+ */
+public class CombinedChannelDuplexHandler extends ChannelDuplexHandler {
+
+    private ChannelStateHandler stateHandler;
+    private ChannelOperationHandler operationHandler;
+
+    /**
+     * Creates a new uninitialized instance. A class that extends this handler must invoke
+     * {@link #init(ChannelStateHandler, ChannelOperationHandler)} before adding this handler into a
+     * {@link ChannelPipeline}.
+     */
+    protected CombinedChannelDuplexHandler() { }
+
+    /**
+     * Creates a new instance that combines the specified two handlers into one.
+     */
+    public CombinedChannelDuplexHandler(ChannelStateHandler stateHandler, ChannelOperationHandler operationHandler) {
+        init(stateHandler, operationHandler);
+    }
+
+    /**
+     * Initialized this handler with the specified handlers.
+     *
+     * @throws IllegalStateException if this handler was not constructed via the default constructor or
+     *                               if this handler does not implement all required handler interfaces
+     * @throws IllegalArgumentException if the specified handlers cannot be combined into one due to a conflict
+     *                                  in the type hierarchy
+     */
+    protected final void init(ChannelStateHandler stateHandler, ChannelOperationHandler operationHandler) {
+        validate(stateHandler, operationHandler);
+        this.stateHandler = stateHandler;
+        this.operationHandler = operationHandler;
+    }
+
+    @SuppressWarnings("InstanceofIncompatibleInterface")
+    private void validate(ChannelStateHandler stateHandler, ChannelOperationHandler operationHandler) {
+        if (this.stateHandler != null) {
+            throw new IllegalStateException(
+                    "init() can not be invoked if " + CombinedChannelDuplexHandler.class.getSimpleName() +
+                            " was constructed with non-default constructor.");
+        }
+
+        if (stateHandler == null) {
+            throw new NullPointerException("stateHandler");
+        }
+        if (operationHandler == null) {
+            throw new NullPointerException("operationHandler");
+        }
+        if (stateHandler instanceof ChannelOperationHandler) {
+            throw new IllegalArgumentException(
+                    "stateHandler must not implement " +
+                    ChannelOperationHandler.class.getSimpleName() + " to get combined.");
+        }
+        if (operationHandler instanceof ChannelStateHandler) {
+            throw new IllegalArgumentException(
+                    "operationHandler must not implement " +
+                    ChannelStateHandler.class.getSimpleName() + " to get combined.");
+        }
+
+        if (stateHandler instanceof ChannelInboundByteHandler && !(this instanceof ChannelInboundByteHandler)) {
+            throw new IllegalStateException(
+                    getClass().getSimpleName() + " must implement " + ChannelInboundByteHandler.class.getSimpleName() +
+                    " if stateHandler implements " + ChannelInboundByteHandler.class.getSimpleName());
+        }
+
+        if (stateHandler instanceof ChannelInboundMessageHandler && !(this instanceof ChannelInboundMessageHandler)) {
+            throw new IllegalStateException(
+                    getClass().getSimpleName() + " must implement " +
+                    ChannelInboundMessageHandler.class.getSimpleName() + " if stateHandler implements " +
+                    ChannelInboundMessageHandler.class.getSimpleName());
+        }
+
+        if (operationHandler instanceof ChannelOutboundByteHandler && !(this instanceof ChannelOutboundByteHandler)) {
+            throw new IllegalStateException(
+                    getClass().getSimpleName() + " must implement " +
+                    ChannelOutboundByteHandler.class.getSimpleName() + " if operationHandler implements " +
+                    ChannelOutboundByteHandler.class.getSimpleName());
+        }
+
+        if (operationHandler instanceof ChannelOutboundMessageHandler &&
+            !(this instanceof ChannelOutboundMessageHandler)) {
+            throw new IllegalStateException(
+                    getClass().getSimpleName() + " must implement " +
+                    ChannelOutboundMessageHandler.class.getSimpleName() + " if operationHandler implements " +
+                    ChannelOutboundMessageHandler.class.getSimpleName());
+        }
+    }
+
+    protected final ChannelStateHandler stateHandler() {
+        return stateHandler;
+    }
+
+    protected final ChannelOperationHandler operationHandler() {
+        return operationHandler;
+    }
+
+    @Override
+    public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
+        if (stateHandler == null) {
+            throw new IllegalStateException(
+                    "init() must be invoked before being added to a " + ChannelPipeline.class.getSimpleName() +
+                    " if " +  CombinedChannelDuplexHandler.class.getSimpleName() +
+                    " was constructed with the default constructor.");
+        }
+
+        try {
+            stateHandler.beforeAdd(ctx);
+        } finally {
+            operationHandler.beforeAdd(ctx);
+        }
+    }
+
+    @Override
+    public void afterAdd(ChannelHandlerContext ctx) throws Exception {
+        try {
+            stateHandler.afterAdd(ctx);
+        } finally {
+            operationHandler.afterAdd(ctx);
+        }
+    }
+
+    @Override
+    public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
+        try {
+            stateHandler.beforeRemove(ctx);
+        } finally {
+            operationHandler.beforeRemove(ctx);
+        }
+    }
+
+    @Override
+    public void afterRemove(ChannelHandlerContext ctx) throws Exception {
+        try {
+            stateHandler.afterRemove(ctx);
+        } finally {
+            operationHandler.afterRemove(ctx);
+        }
+    }
+
+    @Override
+    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
+        stateHandler.channelRegistered(ctx);
+    }
+
+    @Override
+    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
+        stateHandler.channelUnregistered(ctx);
+    }
+
+    @Override
+    public void channelActive(ChannelHandlerContext ctx) throws Exception {
+        stateHandler.channelActive(ctx);
+    }
+
+    @Override
+    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+        stateHandler.channelInactive(ctx);
+    }
+
+    @Override
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+        stateHandler.exceptionCaught(ctx, cause);
+    }
+
+    @Override
+    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
+        stateHandler.userEventTriggered(ctx, evt);
+    }
+
+    @Override
+    public void inboundBufferUpdated(ChannelHandlerContext ctx) throws Exception {
+        stateHandler.inboundBufferUpdated(ctx);
+        if (stateHandler instanceof ChannelInboundByteHandler) {
+            ((ChannelInboundByteHandler) stateHandler).discardInboundReadBytes(ctx);
+        }
+    }
+
+    @Override
+    public void bind(
+            ChannelHandlerContext ctx,
+            SocketAddress localAddress, ChannelPromise promise) throws Exception {
+        operationHandler.bind(ctx, localAddress, promise);
+    }
+
+    @Override
+    public void connect(
+            ChannelHandlerContext ctx,
+            SocketAddress remoteAddress, SocketAddress localAddress,
+            ChannelPromise promise) throws Exception {
+        operationHandler.connect(ctx, remoteAddress, localAddress, promise);
+    }
+
+    @Override
+    public void disconnect(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+        operationHandler.disconnect(ctx, promise);
+    }
+
+    @Override
+    public void close(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+        operationHandler.close(ctx, promise);
+    }
+
+    @Override
+    public void deregister(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+        operationHandler.deregister(ctx, promise);
+    }
+
+    @Override
+    public void read(ChannelHandlerContext ctx) {
+        operationHandler.read(ctx);
+    }
+
+    @Override
+    public void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
+        operationHandler.flush(ctx, promise);
+    }
+
+    @Override
+    public void sendFile(ChannelHandlerContext ctx, FileRegion region, ChannelPromise promise) throws Exception {
+        operationHandler.sendFile(ctx, region, promise);
+    }
+}

transport/src/main/java/io/netty/channel/CombinedChannelHandler.java

@@ -1,225 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.channel;
-
-import io.netty.buffer.Buf;
-
-import java.net.SocketAddress;
-
-/**
- *  Combines a {@link ChannelInboundHandler} and a {@link ChannelOutboundHandler} into one {@link ChannelHandler}.
- *
- */
-public class CombinedChannelHandler extends ChannelStateHandlerAdapter implements ChannelInboundHandler,
-        ChannelOutboundHandler {
-
-    private ChannelOutboundHandler out;
-    private ChannelInboundHandler in;
-
-    protected CombinedChannelHandler() {
-        // User will call init in the subclass constructor.
-    }
-
-    /**
-     * Combine the given {@link ChannelInboundHandler} and {@link ChannelOutboundHandler}.
-     */
-    public CombinedChannelHandler(
-            ChannelInboundHandler inboundHandler, ChannelOutboundHandler outboundHandler) {
-        init(inboundHandler, outboundHandler);
-    }
-
-    /**
-     * Needs to get called before the handler can be added to the {@link ChannelPipeline}.
-     * Otherwise it will trigger a {@link IllegalStateException} later.
-     *
-     */
-    protected void init(ChannelInboundHandler inboundHandler, ChannelOutboundHandler outboundHandler) {
-        if (inboundHandler == null) {
-            throw new NullPointerException("inboundHandler");
-        }
-        if (outboundHandler == null) {
-            throw new NullPointerException("outboundHandler");
-        }
-        if (inboundHandler instanceof ChannelOperationHandler) {
-            throw new IllegalArgumentException(
-                    "inboundHandler must not implement " +
-                    ChannelOperationHandler.class.getSimpleName() + " to get combined.");
-        }
-        if (outboundHandler instanceof ChannelStateHandler) {
-            throw new IllegalArgumentException(
-                    "outboundHandler must not implement " +
-                    ChannelStateHandler.class.getSimpleName() + " to get combined.");
-        }
-
-        if (in != null) {
-            throw new IllegalStateException("init() cannot be called more than once.");
-        }
-
-        in = inboundHandler;
-        out = outboundHandler;
-    }
-
-    @Override
-    public Buf newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        return in.newInboundBuffer(ctx);
-    }
-
-    @Override
-    public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        in.freeInboundBuffer(ctx);
-    }
-
-    @Override
-    public Buf newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        return out.newOutboundBuffer(ctx);
-    }
-
-    @Override
-    public void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
-        out.freeOutboundBuffer(ctx);
-    }
-
-    @Override
-    public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
-        if (in == null) {
-            throw new IllegalStateException(
-                    "not initialized yet - call init() in the constructor of the subclass");
-        }
-
-        try {
-            in.beforeAdd(ctx);
-        } finally {
-            out.beforeAdd(ctx);
-        }
-    }
-
-    @Override
-    public void afterAdd(ChannelHandlerContext ctx) throws Exception {
-        try {
-            in.afterAdd(ctx);
-        } finally {
-            out.afterAdd(ctx);
-        }
-    }
-
-    @Override
-    public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
-        try {
-            in.beforeRemove(ctx);
-        } finally {
-            out.beforeRemove(ctx);
-        }
-    }
-
-    @Override
-    public void afterRemove(ChannelHandlerContext ctx) throws Exception {
-        try {
-            in.afterRemove(ctx);
-        } finally {
-            out.afterRemove(ctx);
-        }
-    }
-
-    @Override
-    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
-        in.channelRegistered(ctx);
-    }
-
-    @Override
-    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
-        in.channelUnregistered(ctx);
-    }
-
-    @Override
-    public void channelActive(ChannelHandlerContext ctx) throws Exception {
-        in.channelActive(ctx);
-    }
-
-    @Override
-    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
-        in.channelInactive(ctx);
-    }
-
-    @Override
-    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-        in.exceptionCaught(ctx, cause);
-    }
-
-    @Override
-    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
-        in.userEventTriggered(ctx, evt);
-    }
-
-    @Override
-    public void inboundBufferUpdated(ChannelHandlerContext ctx) throws Exception {
-        in.inboundBufferUpdated(ctx);
-        if (in instanceof ChannelInboundByteHandler) {
-            ((ChannelInboundByteHandler) in).discardInboundReadBytes(ctx);
-        }
-    }
-
-    @Override
-    public void bind(
-            ChannelHandlerContext ctx,
-            SocketAddress localAddress, ChannelPromise promise) throws Exception {
-        out.bind(ctx, localAddress, promise);
-    }
-
-    @Override
-    public void connect(
-            ChannelHandlerContext ctx,
-            SocketAddress remoteAddress, SocketAddress localAddress,
-            ChannelPromise promise) throws Exception {
-        out.connect(ctx, remoteAddress, localAddress, promise);
-    }
-
-    @Override
-    public void disconnect(
-            ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-        out.disconnect(ctx, promise);
-    }
-
-    @Override
-    public void close(
-            ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-        out.close(ctx, promise);
-    }
-
-    @Override
-    public void deregister(
-            ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-        out.deregister(ctx, promise);
-    }
-
-    @Override
-    public void read(ChannelHandlerContext ctx) {
-        out.read(ctx);
-    }
-
-    @Override
-    public void flush(
-            ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-        out.flush(ctx, promise);
-        if (out instanceof ChannelOutboundByteHandler) {
-            ((ChannelOutboundByteHandler) out).discardOutboundReadBytes(ctx);
-        }
-    }
-
-    @Override
-    public void sendFile(ChannelHandlerContext ctx, FileRegion region, ChannelPromise promise) throws Exception {
-        out.sendFile(ctx, region, promise);
-    }
-}

transport/src/main/java/io/netty/channel/DefaultChannelHandlerContext.java

@@ -20,6 +20,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
+import io.netty.channel.DefaultChannelPipeline.*;
 import io.netty.util.DefaultAttributeMap;
 
 import java.net.SocketAddress;
@@ -67,9 +68,13 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     //
     // Note we use an AtomicReferenceFieldUpdater for atomic operations on these to safe memory. This will safe us
     // 64 bytes per Bridge.
+    @SuppressWarnings("UnusedDeclaration")
     private volatile MessageBridge inMsgBridge;
+    @SuppressWarnings("UnusedDeclaration")
     private volatile MessageBridge outMsgBridge;
+    @SuppressWarnings("UnusedDeclaration")
     private volatile ByteBridge inByteBridge;
+    @SuppressWarnings("UnusedDeclaration")
     private volatile ByteBridge outByteBridge;
 
     private static final AtomicReferenceFieldUpdater<DefaultChannelHandlerContext, MessageBridge> IN_MSG_BRIDGE_UPDATER
@@ -94,22 +99,15 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     private Runnable invokeChannelInactiveTask;
     private Runnable invokeInboundBufferUpdatedTask;
     private Runnable fireInboundBufferUpdated0Task;
-    private Runnable invokeInboundBufferSuspendedTask;
+    private Runnable invokeChannelReadSuspendedTask;
     private Runnable invokeFreeInboundBuffer0Task;
     private Runnable invokeFreeOutboundBuffer0Task;
     private Runnable invokeRead0Task;
     volatile boolean removed;
 
-    DefaultChannelHandlerContext(
-            DefaultChannelPipeline pipeline, EventExecutorGroup group,
-            String name, ChannelHandler handler) {
-        this(pipeline, group, name, handler, false);
-    }
-
     @SuppressWarnings("unchecked")
     DefaultChannelHandlerContext(
-            DefaultChannelPipeline pipeline, EventExecutorGroup group,
+            DefaultChannelPipeline pipeline, EventExecutorGroup group, String name, ChannelHandler handler) {
-            String name, ChannelHandler handler, boolean needsLazyBufInit) {
 
         if (name == null) {
             throw new NullPointerException("name");
@@ -157,44 +155,63 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             try {
                 buf = ((ChannelInboundHandler) handler).newInboundBuffer(this);
             } catch (Exception e) {
-                throw new ChannelPipelineException("A user handler failed to create a new inbound buffer.", e);
+                throw new ChannelPipelineException(
-            }
+                        handler.getClass().getSimpleName() + ".newInboundBuffer() raised an exception.", e);
-
-            if (buf == null) {
-                throw new ChannelPipelineException("A user handler's newInboundBuffer() returned null");
             }
 
             if (buf instanceof ByteBuf) {
                 inByteBuf = (ByteBuf) buf;
-                inByteBridge = null;
-                inMsgBuf = null;
-                inMsgBridge = null;
             } else if (buf instanceof MessageBuf) {
-                inByteBuf = null;
-                inByteBridge = null;
                 inMsgBuf = (MessageBuf<Object>) buf;
-                inMsgBridge = null;
             } else {
-                throw new Error();
+                throw new ChannelPipelineException(
+                        handler.getClass().getSimpleName() + ".newInboundBuffer() returned neither " +
+                        ByteBuf.class.getSimpleName() + " nor " + MessageBuf.class.getSimpleName() + ": " + buf);
             }
-        } else {
-            inByteBridge = null;
-            inMsgBridge = null;
         }
 
         if (handler instanceof ChannelOutboundHandler) {
-            if (needsLazyBufInit) {
+            Buf buf;
-                // Special case: it means this context is for HeadHandler.
+            try {
-                // HeadHandler is an outbound handler instantiated by the constructor of DefaultChannelPipeline.
+                buf = ((ChannelOutboundHandler) handler).newOutboundBuffer(this);
-                // Because Channel is not really fully initialized at this point, we should not call
+            } catch (Exception e) {
-                // newOutboundBuffer() yet because it will usually lead to NPE.
+                throw new ChannelPipelineException(
-                // To work around this problem, we lazily initialize the outbound buffer for this special case.
+                        handler.getClass().getSimpleName() + ".newOutboundBuffer() raised an exception.", e);
+            }
+
+            if (buf instanceof ByteBuf) {
+                outByteBuf = (ByteBuf) buf;
+            } else if (buf instanceof MessageBuf) {
+                @SuppressWarnings("unchecked")
+                MessageBuf<Object> msgBuf = (MessageBuf<Object>) buf;
+                outMsgBuf = msgBuf;
             } else {
-                initOutboundBuffer();
+                throw new ChannelPipelineException(
+                        handler.getClass().getSimpleName() + ".newOutboundBuffer() returned neither " +
+                        ByteBuf.class.getSimpleName() + " nor " + MessageBuf.class.getSimpleName() + ": " + buf);
+            }
         }
     }
 
-        this.needsLazyBufInit = needsLazyBufInit;
+    DefaultChannelHandlerContext(DefaultChannelPipeline pipeline, String name, HeadHandler handler) {
+        type = null;
+        channel = pipeline.channel;
+        this.pipeline = pipeline;
+        this.name = name;
+        this.handler = handler;
+        executor = null;
+        needsLazyBufInit = true;
+    }
+
+    DefaultChannelHandlerContext(DefaultChannelPipeline pipeline, String name, TailHandler handler) {
+        type = null;
+        channel = pipeline.channel;
+        this.pipeline = pipeline;
+        this.name = name;
+        this.handler = handler;
+        executor = null;
+        inByteBuf = handler.byteSink;
+        inMsgBuf = handler.msgSink;
     }
 
     void forwardBufferContent() {
@@ -233,19 +250,23 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         }
     }
 
-    private void lazyInitOutboundBuffer() {
+    private void lazyInitHeadHandler() {
         if (needsLazyBufInit) {
-            if (outByteBuf == null && outMsgBuf == null) {
-                needsLazyBufInit = false;
             EventExecutor exec = executor();
             if (exec.inEventLoop()) {
-                    initOutboundBuffer();
+                if (needsLazyBufInit) {
+                    needsLazyBufInit = false;
+                    HeadHandler headHandler = (HeadHandler) handler;
+                    headHandler.init(this);
+                    outByteBuf = headHandler.byteSink;
+                    outMsgBuf = headHandler.msgSink;
+                }
             } else {
                 try {
                     getFromFuture(exec.submit(new Runnable() {
                         @Override
                         public void run() {
-                                lazyInitOutboundBuffer();
+                            lazyInitHeadHandler();
                         }
                     }));
                 } catch (Exception e) {
@@ -254,36 +275,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             }
         }
     }
-    }
-
-    private void initOutboundBuffer() {
-        Buf buf;
-        try {
-            buf = ((ChannelOutboundHandler) handler()).newOutboundBuffer(this);
-        } catch (Exception e) {
-            throw new ChannelPipelineException("A user handler failed to create a new outbound buffer.", e);
-        }
-
-        if (buf == null) {
-            throw new ChannelPipelineException("A user handler's newOutboundBuffer() returned null");
-        }
-
-        if (buf instanceof ByteBuf) {
-            outByteBuf = (ByteBuf) buf;
-            outByteBridge = null;
-            outMsgBuf = null;
-            outMsgBridge = null;
-        } else if (buf instanceof MessageBuf) {
-            outByteBuf = null;
-            outByteBridge = null;
-            @SuppressWarnings("unchecked")
-            MessageBuf<Object> msgBuf = (MessageBuf<Object>) buf;
-            outMsgBuf = msgBuf;
-            outMsgBridge = null;
-        } else {
-            throw new Error();
-        }
-    }
 
     private void fillBridge() {
         if (inMsgBridge != null) {
@@ -708,88 +699,16 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         return currentOutboundMsgBuf;
     }
 
-    @Override
-    public boolean hasNextInboundByteBuffer() {
-        DefaultChannelHandlerContext ctx = next;
-        for (;;) {
-            if (ctx == null) {
-                return false;
-            }
-            if (ctx.hasInboundByteBuffer()) {
-                return true;
-            }
-            ctx = ctx.next;
-        }
-    }
-
-    @Override
-    public boolean hasNextInboundMessageBuffer() {
-        DefaultChannelHandlerContext ctx = next;
-        for (;;) {
-            if (ctx == null) {
-                return false;
-            }
-            if (ctx.hasInboundMessageBuffer()) {
-                return true;
-            }
-            ctx = ctx.next;
-        }
-    }
-
-    @Override
-    public boolean hasNextOutboundByteBuffer() {
-        DefaultChannelHandlerContext ctx = prev;
-        for (;;) {
-            if (ctx == null) {
-                return false;
-            }
-
-            if (ctx.hasOutboundByteBuffer()) {
-                return true;
-            }
-
-            ctx = ctx.prev;
-        }
-    }
-
-    @Override
-    public boolean hasNextOutboundMessageBuffer() {
-        DefaultChannelHandlerContext ctx = prev;
-        for (;;) {
-            if (ctx == null) {
-                return false;
-            }
-
-            if (ctx.hasOutboundMessageBuffer()) {
-                return true;
-            }
-
-            ctx = ctx.prev;
-        }
-    }
-
     @Override
     public ByteBuf nextInboundByteBuffer() {
         DefaultChannelHandlerContext ctx = next;
         for (;;) {
-            if (ctx == null) {
-                if (prev != null) {
-                    throw new NoSuchBufferException(String.format(
-                            "the handler '%s' could not find a %s whose inbound buffer is %s.",
-                            name, ChannelInboundHandler.class.getSimpleName(),
-                            ByteBuf.class.getSimpleName()));
-                } else {
-                    throw new NoSuchBufferException(String.format(
-                            "the pipeline does not contain a %s whose inbound buffer is %s.",
-                            ChannelInboundHandler.class.getSimpleName(),
-                            ByteBuf.class.getSimpleName()));
-                }
-            }
             if (ctx.hasInboundByteBuffer()) {
-                if (ctx.executor().inEventLoop()) {
+                Thread currentThread = Thread.currentThread();
-                    return ctx.inboundByteBuffer();
+                if (ctx.executor().inEventLoop(currentThread)) {
+                    return ctx.inByteBuf;
                 }
-                if (executor().inEventLoop()) {
+                if (executor().inEventLoop(currentThread)) {
                     ByteBridge bridge = ctx.inByteBridge;
                     if (bridge == null) {
                         bridge = new ByteBridge(ctx);
@@ -809,25 +728,12 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     public MessageBuf<Object> nextInboundMessageBuffer() {
         DefaultChannelHandlerContext ctx = next;
         for (;;) {
-            if (ctx == null) {
-                if (prev != null) {
-                    throw new NoSuchBufferException(String.format(
-                            "the handler '%s' could not find a %s whose inbound buffer is %s.",
-                            name, ChannelInboundHandler.class.getSimpleName(),
-                            MessageBuf.class.getSimpleName()));
-                } else {
-                    throw new NoSuchBufferException(String.format(
-                            "the pipeline does not contain a %s whose inbound buffer is %s.",
-                            ChannelInboundHandler.class.getSimpleName(),
-                            MessageBuf.class.getSimpleName()));
-                }
-            }
-
             if (ctx.hasInboundMessageBuffer()) {
-                if (ctx.executor().inEventLoop()) {
+                Thread currentThread = Thread.currentThread();
-                    return ctx.inboundMessageBuffer();
+                if (ctx.executor().inEventLoop(currentThread)) {
+                    return ctx.inMsgBuf;
                 }
-                if (executor().inEventLoop()) {
+                if (executor().inEventLoop(currentThread)) {
                     MessageBridge bridge = ctx.inMsgBridge;
                     if (bridge == null) {
                         bridge = new MessageBridge();
@@ -846,13 +752,13 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     @Override
     public ByteBuf nextOutboundByteBuffer() {
         DefaultChannelHandlerContext ctx = prev;
-        final DefaultChannelHandlerContext initialCtx = ctx;
         for (;;) {
             if (ctx.hasOutboundByteBuffer()) {
-                if (ctx.executor().inEventLoop()) {
+                Thread currentThread = Thread.currentThread();
+                if (ctx.executor().inEventLoop(currentThread)) {
                     return ctx.outboundByteBuffer();
                 }
-                if (executor().inEventLoop()) {
+                if (executor().inEventLoop(currentThread)) {
                     ByteBridge bridge = ctx.outByteBridge;
                     if (bridge == null) {
                         bridge = new ByteBridge(ctx);
@@ -865,33 +771,19 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 throw new IllegalStateException("nextOutboundByteBuffer() called from outside the eventLoop");
             }
             ctx = ctx.prev;
-
-            if (ctx == null) {
-                if (initialCtx != null && initialCtx.next != null) {
-                    throw new NoSuchBufferException(String.format(
-                            "the handler '%s' could not find a %s whose outbound buffer is %s.",
-                            initialCtx.next.name(), ChannelOutboundHandler.class.getSimpleName(),
-                            ByteBuf.class.getSimpleName()));
-                } else {
-                    throw new NoSuchBufferException(String.format(
-                            "the pipeline does not contain a %s whose outbound buffer is %s.",
-                            ChannelOutboundHandler.class.getSimpleName(),
-                            ByteBuf.class.getSimpleName()));
-                }
-            }
         }
     }
 
     @Override
     public MessageBuf<Object> nextOutboundMessageBuffer() {
         DefaultChannelHandlerContext ctx = prev;
-        final DefaultChannelHandlerContext initialCtx = ctx;
         for (;;) {
             if (ctx.hasOutboundMessageBuffer()) {
-                if (ctx.executor().inEventLoop()) {
+                Thread currentThread = Thread.currentThread();
+                if (ctx.executor().inEventLoop(currentThread)) {
                     return ctx.outboundMessageBuffer();
                 }
-                if (executor().inEventLoop()) {
+                if (executor().inEventLoop(currentThread)) {
                     MessageBridge bridge = ctx.outMsgBridge;
                     if (bridge == null) {
                         bridge = new MessageBridge();
@@ -904,28 +796,13 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 throw new IllegalStateException("nextOutboundMessageBuffer() called from outside the eventLoop");
             }
             ctx = ctx.prev;
-
-            if (ctx == null) {
-                if (initialCtx.next != null) {
-                    throw new NoSuchBufferException(String.format(
-                            "the handler '%s' could not find a %s whose outbound buffer is %s.",
-                            initialCtx.next.name(), ChannelOutboundHandler.class.getSimpleName(),
-                            MessageBuf.class.getSimpleName()));
-                } else {
-                    throw new NoSuchBufferException(String.format(
-                            "the pipeline does not contain a %s whose outbound buffer is %s.",
-                            ChannelOutboundHandler.class.getSimpleName(),
-                            MessageBuf.class.getSimpleName()));
-                }
-            }
         }
     }
 
     @Override
     public void fireChannelRegistered() {
-        lazyInitOutboundBuffer();
+        lazyInitHeadHandler();
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (executor.inEventLoop()) {
             next.invokeChannelRegistered();
@@ -942,7 +819,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             executor.execute(task);
         }
     }
-    }
 
     private void invokeChannelRegistered() {
         try {
@@ -957,7 +833,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     @Override
     public void fireChannelUnregistered() {
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (prev != null && executor.inEventLoop()) {
             next.invokeChannelUnregistered();
@@ -974,7 +849,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             executor.execute(task);
         }
     }
-    }
 
     private void invokeChannelUnregistered() {
         try {
@@ -986,8 +860,8 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     @Override
     public void fireChannelActive() {
+        lazyInitHeadHandler();
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (executor.inEventLoop()) {
             next.invokeChannelActive();
@@ -1004,7 +878,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             executor.execute(task);
         }
     }
-    }
 
     private void invokeChannelActive() {
         try {
@@ -1019,7 +892,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     @Override
     public void fireChannelInactive() {
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (prev != null && executor.inEventLoop()) {
             next.invokeChannelInactive();
@@ -1036,7 +908,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             executor.execute(task);
         }
     }
-    }
 
     private void invokeChannelInactive() {
         try {
@@ -1055,7 +926,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         }
 
         final DefaultChannelHandlerContext next = this.next;
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (prev != null && executor.inEventLoop()) {
             next.invokeExceptionCaught(cause);
@@ -1074,12 +944,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
                 }
             }
         }
-        } else {
-            logger.warn(
-                    "An exceptionCaught() event was fired, and it reached at the end of the " +
-                            "pipeline.  It usually means the last inbound handler in the pipeline did not " +
-                            "handle the exception.", cause);
-        }
     }
 
     private void invokeExceptionCaught(Throwable cause) {
@@ -1103,7 +967,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         }
 
         final DefaultChannelHandlerContext next = this.next;
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (executor.inEventLoop()) {
             next.invokeUserEventTriggered(event);
@@ -1116,7 +979,6 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             });
         }
     }
-    }
 
     private void invokeUserEventTriggered(Object event) {
         try {
@@ -1149,7 +1011,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
 
     private void fireInboundBufferUpdated0() {
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null && !next.isInboundBufferFreed()) {
+        if (!next.isInboundBufferFreed()) {
             next.fillBridge();
             // This comparison is safe because this method is always executed from the executor.
             if (next.executor == executor) {
@@ -1191,28 +1053,26 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
     }
 
     @Override
-    public void fireInboundBufferSuspended() {
+    public void fireChannelReadSuspended() {
         final DefaultChannelHandlerContext next = findContextInbound();
-        if (next != null) {
         EventExecutor executor = next.executor();
         if (prev != null && executor.inEventLoop()) {
-                next.invokeInboundBufferSuspended();
+            next.invokeChannelReadSuspended();
         } else {
-                Runnable task = next.invokeInboundBufferSuspendedTask;
+            Runnable task = next.invokeChannelReadSuspendedTask;
             if (task == null) {
-                    next.invokeInboundBufferSuspendedTask = task = new Runnable() {
+                next.invokeChannelReadSuspendedTask = task = new Runnable() {
                     @Override
                     public void run() {
-                            next.invokeInboundBufferSuspended();
+                        next.invokeChannelReadSuspended();
                     }
                 };
             }
             executor.execute(task);
         }
     }
-    }
 
-    private void invokeInboundBufferSuspended() {
+    private void invokeChannelReadSuspended() {
         try {
             ((ChannelStateHandler) handler()).channelReadSuspended(this);
         } catch (Throwable t) {
@@ -1701,12 +1561,12 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             }
         }
 
+        if (next != null) {
             DefaultChannelHandlerContext nextCtx = findContextInbound();
-        if (nextCtx != null) {
             nextCtx.invokeFreeInboundBuffer();
         } else {
             // Freed all inbound buffers. Free all outbound buffers in a reverse order.
-            pipeline.tail.findContextOutbound().invokeFreeOutboundBuffer();
+            findContextOutbound().invokeFreeOutboundBuffer();
         }
     }
 
@@ -1741,9 +1601,8 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
             }
         }
 
-        DefaultChannelHandlerContext nextCtx = findContextOutbound();
+        if (prev != null) {
-        if (nextCtx != null) {
+            findContextOutbound().invokeFreeOutboundBuffer();
-            nextCtx.invokeFreeOutboundBuffer();
         }
     }
 
@@ -1790,7 +1649,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         DefaultChannelHandlerContext ctx = this;
         do {
             ctx = ctx.next;
-        } while (ctx != null && !(ctx.handler() instanceof ChannelStateHandler));
+        } while (!(ctx.handler() instanceof ChannelStateHandler));
         return ctx;
     }
 
@@ -1798,7 +1657,7 @@ final class DefaultChannelHandlerContext extends DefaultAttributeMap implements
         DefaultChannelHandlerContext ctx = this;
         do {
             ctx = ctx.prev;
-        } while (ctx != null && !(ctx.handler() instanceof ChannelOperationHandler));
+        } while (!(ctx.handler() instanceof ChannelOperationHandler));
         return ctx;
     }
 

transport/src/main/java/io/netty/channel/DefaultChannelPipeline.java

@@ -15,6 +15,7 @@
  */
 package io.netty.channel;
 
+import io.netty.buffer.Buf;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Freeable;
 import io.netty.buffer.MessageBuf;
@@ -56,7 +57,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
     final Map<EventExecutorGroup, EventExecutor> childExecutors =
             new IdentityHashMap<EventExecutorGroup, EventExecutor>();
 
-    private static final TailHandler TAIL_HANDLER = new TailHandler();
     volatile boolean inboundBufferFreed;
     volatile boolean outboundBufferFreed;
 
@@ -66,7 +66,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
         }
         this.channel = channel;
 
-        tail = new DefaultChannelHandlerContext(this, null, generateName(TAIL_HANDLER), TAIL_HANDLER);
+        TailHandler tailHandler = new TailHandler();
+        tail = new DefaultChannelHandlerContext(this, generateName(tailHandler), tailHandler);
 
         HeadHandler headHandler;
         switch (channel.metadata().bufferType()) {
@@ -80,7 +81,7 @@ final class DefaultChannelPipeline implements ChannelPipeline {
             throw new Error("unknown buffer type: " + channel.metadata().bufferType());
         }
 
-        head = new DefaultChannelHandlerContext(this, null, generateName(headHandler), headHandler, true);
+        head = new DefaultChannelHandlerContext(this, generateName(headHandler), headHandler);
 
         head.next = tail;
         tail.prev = head;
@@ -583,8 +584,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
 
     private static void callBeforeAdd(ChannelHandlerContext ctx) {
         ChannelHandler handler = ctx.handler();
-        if (handler instanceof ChannelStateHandlerAdapter) {
+        if (handler instanceof ChannelHandlerAdapter) {
-            ChannelStateHandlerAdapter h = (ChannelStateHandlerAdapter) handler;
+            ChannelHandlerAdapter h = (ChannelHandlerAdapter) handler;
             if (!h.isSharable() && h.added) {
                 throw new ChannelPipelineException(
                         h.getClass().getName()  +
@@ -904,8 +905,8 @@ final class DefaultChannelPipeline implements ChannelPipeline {
     }
 
     @Override
-    public void fireInboundBufferSuspended() {
+    public void fireChannelReadSuspended() {
-        head.fireInboundBufferSuspended();
+        head.fireChannelReadSuspended();
         if (channel.config().isAutoRead()) {
             read();
         }
@@ -1075,22 +1076,110 @@ final class DefaultChannelPipeline implements ChannelPipeline {
         }
     }
 
-    private static final class TailHandler extends ChannelInboundMessageHandlerAdapter<Freeable> {
+    // A special catch-all handler that handles both bytes and messages.
-        public TailHandler() {
+    static final class TailHandler implements ChannelInboundHandler {
-            super(Freeable.class);
+
+        final ByteBuf byteSink = Unpooled.buffer(0);
+        final MessageBuf<Object> msgSink = Unpooled.messageBuffer(0);
+
+        @Override
+        public void channelRegistered(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void channelUnregistered(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void channelActive(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void channelInactive(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void channelReadSuspended(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void beforeAdd(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void afterAdd(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void beforeRemove(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void afterRemove(ChannelHandlerContext ctx) throws Exception { }
+
+        @Override
+        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception { }
+
+        @Override
+        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+            logger.warn(
+                    "An exceptionCaught() event was fired, and it reached at the end of the pipeline. " +
+                            "It usually means the last handler in the pipeline did not handle the exception.", cause);
         }
 
         @Override
-        protected void messageReceived(ChannelHandlerContext ctx, Freeable msg) throws Exception {
+        public Buf newInboundBuffer(ChannelHandlerContext ctx) throws Exception {
-            if (logger.isWarnEnabled()) {
+            throw new Error();
-                logger.warn("Freeable reached end-of-pipeline, call " + msg + ".free() to" +
+        }
-                        " guard against resource leakage!");
+
+        @Override
+        public void freeInboundBuffer(ChannelHandlerContext ctx) throws Exception {
+            byteSink.free();
+            msgSink.free();
+        }
+
+        @Override
+        public void inboundBufferUpdated(ChannelHandlerContext ctx) throws Exception {
+            int byteSinkSize = byteSink.readableBytes();
+            if (byteSinkSize != 0) {
+                byteSink.clear();
+                logger.warn(
+                        "Discarded {} inbound byte(s) that reached at the end of the pipeline. " +
+                        "Please check your pipeline configuration.", byteSinkSize);
+            }
+
+            int msgSinkSize = msgSink.size();
+            if (msgSinkSize != 0) {
+                MessageBuf<Object> in = msgSink;
+                for (;;) {
+                    Object m = in.poll();
+                    if (m == null) {
+                        break;
+                    }
+
+                    if (m instanceof Freeable) {
+                        ((Freeable) m).free();
+                    }
+                }
+                logger.warn(
+                        "Discarded {} inbound message(s) that reached at the end of the pipeline. " +
+                        "Please check your pipeline configuration.", msgSinkSize);
             }
-            msg.free();
         }
     }
 
-    private abstract class HeadHandler implements ChannelOutboundHandler {
+    abstract class HeadHandler implements ChannelOutboundHandler {
+
+        ByteBuf byteSink;
+        MessageBuf<Object> msgSink;
+
+        void init(ChannelHandlerContext ctx) {
+            switch (ctx.channel().metadata().bufferType()) {
+            case BYTE:
+                byteSink = ctx.alloc().ioBuffer();
+                msgSink = Unpooled.messageBuffer(0);
+                break;
+            case MESSAGE:
+                byteSink = Unpooled.buffer(0);
+                msgSink = Unpooled.messageBuffer();
+                break;
+            default:
+                throw new Error();
+            }
+        }
+
         @Override
         public final void beforeAdd(ChannelHandlerContext ctx) throws Exception {
             // NOOP
@@ -1146,11 +1235,6 @@ final class DefaultChannelPipeline implements ChannelPipeline {
             unsafe.beginRead();
         }
 
-        @Override
-        public final void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-            unsafe.flush(promise);
-        }
-
         @Override
         public final void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
             ctx.fireExceptionCaught(cause);
@@ -1166,36 +1250,54 @@ final class DefaultChannelPipeline implements ChannelPipeline {
                 ChannelHandlerContext ctx, FileRegion region, ChannelPromise promise) throws Exception {
             unsafe.sendFile(region, promise);
         }
-    }
 
-    private final class ByteHeadHandler extends HeadHandler implements ChannelOutboundByteHandler {
         @Override
-        public ByteBuf newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        public final Buf newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
-            return ctx.alloc().ioBuffer();
+            throw new Error();
         }
 
         @Override
-        public void discardOutboundReadBytes(ChannelHandlerContext ctx) throws Exception {
+        public final void freeOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
-            if (ctx.hasOutboundByteBuffer()) {
+            msgSink.free();
-                ctx.outboundByteBuffer().discardSomeReadBytes();
+            byteSink.free();
         }
     }
 
+    private final class ByteHeadHandler extends HeadHandler {
         @Override
-        public void freeOutboundBuffer(ChannelHandlerContext ctx) {
+        public void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-            ctx.outboundByteBuffer().free();
+            int msgSinkSize = msgSink.size();
+            if (msgSinkSize != 0) {
+                MessageBuf<Object> in = msgSink;
+                for (;;) {
+                    Object m = in.poll();
+                    if (m == null) {
+                        break;
+                    }
+
+                    if (m instanceof Freeable) {
+                        ((Freeable) m).free();
+                    }
+                }
+                logger.warn(
+                        "Discarded {} outbound message(s) that reached at the end of the pipeline. " +
+                                "Please check your pipeline configuration.", msgSinkSize);
+            }
+            unsafe.flush(promise);
         }
     }
 
-    private final class MessageHeadHandler extends HeadHandler implements ChannelOutboundMessageHandler<Object> {
+    private final class MessageHeadHandler extends HeadHandler {
         @Override
-        public MessageBuf<Object> newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
+        public void flush(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception {
-            return Unpooled.messageBuffer();
+            int byteSinkSize = byteSink.readableBytes();
+            if (byteSinkSize != 0) {
+                byteSink.clear();
+                logger.warn(
+                        "Discarded {} outbound byte(s) that reached at the end of the pipeline. " +
+                                "Please check your pipeline configuration.", byteSinkSize);
             }
-
+            unsafe.flush(promise);
-        @Override
-        public void freeOutboundBuffer(ChannelHandlerContext ctx) {
-            ctx.outboundMessageBuffer().free();
         }
     }
 }

transport/src/main/java/io/netty/channel/local/LocalChannel.java

@@ -222,7 +222,7 @@ public class LocalChannel extends AbstractChannel {
         }
 
         pipeline.fireInboundBufferUpdated();
-        pipeline.fireInboundBufferSuspended();
+        pipeline.fireChannelReadSuspended();
     }
 
     @Override
@@ -259,7 +259,7 @@ public class LocalChannel extends AbstractChannel {
         if (peer.readInProgress) {
             peer.readInProgress = false;
             peerPipeline.fireInboundBufferUpdated();
-            peerPipeline.fireInboundBufferSuspended();
+            peerPipeline.fireChannelReadSuspended();
         }
     }
 

transport/src/main/java/io/netty/channel/local/LocalServerChannel.java

@@ -144,7 +144,7 @@ public class LocalServerChannel extends AbstractServerChannel {
         }
 
         pipeline.fireInboundBufferUpdated();
-        pipeline.fireInboundBufferSuspended();
+        pipeline.fireChannelReadSuspended();
     }
 
     LocalChannel serve(final LocalChannel peer) {
@@ -160,7 +160,7 @@ public class LocalServerChannel extends AbstractServerChannel {
             if (acceptInProgress) {
                 acceptInProgress = false;
                 pipeline.fireInboundBufferUpdated();
-                pipeline.fireInboundBufferSuspended();
+                pipeline.fireChannelReadSuspended();
             }
         } else {
             eventLoop().execute(new Runnable() {

transport/src/main/java/io/netty/channel/nio/AbstractNioByteChannel.java

@@ -65,7 +65,7 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
             final ByteBuf byteBuf = pipeline.inboundByteBuffer();
             boolean closed = false;
             boolean read = false;
-            boolean firedInboundBufferSuspended = false;
+            boolean firedChannelReadSuspended = false;
             try {
                 expandReadBuffer(byteBuf);
                 loop: for (;;) {
@@ -106,8 +106,8 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
                 if (t instanceof IOException) {
                     closed = true;
                 } else if (!closed) {
-                    firedInboundBufferSuspended = true;
+                    firedChannelReadSuspended = true;
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
                 pipeline().fireExceptionCaught(t);
             } finally {
@@ -124,8 +124,8 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
                             close(voidFuture());
                         }
                     }
-                } else if (!firedInboundBufferSuspended) {
+                } else if (!firedChannelReadSuspended) {
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
             }
         }

transport/src/main/java/io/netty/channel/nio/AbstractNioMessageChannel.java

@@ -55,7 +55,7 @@ public abstract class AbstractNioMessageChannel extends AbstractNioChannel {
             final MessageBuf<Object> msgBuf = pipeline.inboundMessageBuffer();
             boolean closed = false;
             boolean read = false;
-            boolean firedInboundBufferSuspended = false;
+            boolean firedChannelReadSuspended = false;
             try {
                 for (;;) {
                     int localReadAmount = doReadMessages(msgBuf);
@@ -77,8 +77,8 @@ public abstract class AbstractNioMessageChannel extends AbstractNioChannel {
                 if (t instanceof IOException) {
                     closed = true;
                 } else if (!closed) {
-                    firedInboundBufferSuspended = true;
+                    firedChannelReadSuspended = true;
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
 
                 pipeline().fireExceptionCaught(t);
@@ -88,8 +88,8 @@ public abstract class AbstractNioMessageChannel extends AbstractNioChannel {
                 }
                 if (closed && isOpen()) {
                     close(voidFuture());
-                } else if (!firedInboundBufferSuspended) {
+                } else if (!firedChannelReadSuspended) {
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
             }
         }

transport/src/main/java/io/netty/channel/oio/AbstractOioByteChannel.java

@@ -126,7 +126,7 @@ public abstract class AbstractOioByteChannel extends AbstractOioChannel {
                 pipeline.fireExceptionCaught(t);
             } else {
                 firedInboundBufferSuspeneded = true;
-                pipeline.fireInboundBufferSuspended();
+                pipeline.fireChannelReadSuspended();
                 pipeline.fireExceptionCaught(t);
                 unsafe().close(unsafe().voidFuture());
             }
@@ -144,7 +144,7 @@ public abstract class AbstractOioByteChannel extends AbstractOioChannel {
                     }
                 }
             } else if (!firedInboundBufferSuspeneded) {
-                pipeline.fireInboundBufferSuspended();
+                pipeline.fireChannelReadSuspended();
             }
         }
     }

transport/src/main/java/io/netty/channel/oio/AbstractOioMessageChannel.java

@@ -39,7 +39,7 @@ public abstract class AbstractOioMessageChannel extends AbstractOioChannel {
         final MessageBuf<Object> msgBuf = pipeline.inboundMessageBuffer();
         boolean closed = false;
         boolean read = false;
-        boolean firedInboundBufferSuspended = false;
+        boolean firedChannelReadSuspended = false;
         try {
             int localReadAmount = doReadMessages(msgBuf);
             if (localReadAmount > 0) {
@@ -52,8 +52,8 @@ public abstract class AbstractOioMessageChannel extends AbstractOioChannel {
                 read = false;
                 pipeline.fireInboundBufferUpdated();
             }
-            firedInboundBufferSuspended = true;
+            firedChannelReadSuspended = true;
-            pipeline.fireInboundBufferSuspended();
+            pipeline.fireChannelReadSuspended();
             pipeline.fireExceptionCaught(t);
             if (t instanceof IOException) {
                 unsafe().close(unsafe().voidFuture());
@@ -62,8 +62,8 @@ public abstract class AbstractOioMessageChannel extends AbstractOioChannel {
             if (read) {
                 pipeline.fireInboundBufferUpdated();
             }
-            if (!firedInboundBufferSuspended) {
+            if (!firedChannelReadSuspended) {
-                pipeline.fireInboundBufferSuspended();
+                pipeline.fireChannelReadSuspended();
             }
             if (closed && isOpen()) {
                 unsafe().close(unsafe().voidFuture());

transport/src/main/java/io/netty/channel/socket/aio/AioServerSocketChannel.java

@@ -185,7 +185,7 @@ public class AioServerSocketChannel extends AbstractAioChannel implements Server
             channel.pipeline().inboundMessageBuffer().add(
                     new AioSocketChannel(channel, null, ch));
             channel.pipeline().fireInboundBufferUpdated();
-            channel.pipeline().fireInboundBufferSuspended();
+            channel.pipeline().fireChannelReadSuspended();
         }
 
         @Override

transport/src/main/java/io/netty/channel/socket/aio/AioSocketChannel.java

@@ -436,7 +436,7 @@ public class AioSocketChannel extends AbstractAioChannel implements SocketChanne
 
             boolean closed = false;
             boolean read = false;
-            boolean firedInboundBufferSuspended = false;
+            boolean firedChannelReadSuspended = false;
             try {
                 int localReadAmount = result.intValue();
                 if (localReadAmount > 0) {
@@ -458,8 +458,8 @@ public class AioSocketChannel extends AbstractAioChannel implements SocketChanne
                 }
 
                 if (!closed && channel.isOpen()) {
-                    firedInboundBufferSuspended = true;
+                    firedChannelReadSuspended = true;
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
 
                 pipeline.fireExceptionCaught(t);
@@ -478,8 +478,8 @@ public class AioSocketChannel extends AbstractAioChannel implements SocketChanne
                             channel.unsafe().close(channel.unsafe().voidFuture());
                         }
                     }
-                } else if (!firedInboundBufferSuspended) {
+                } else if (!firedChannelReadSuspended) {
-                    pipeline.fireInboundBufferSuspended();
+                    pipeline.fireChannelReadSuspended();
                 }
             }
         }

transport/src/test/java/io/netty/channel/AbstractEventLoopTest.java

@@ -59,11 +59,11 @@ public abstract class AbstractEventLoopTest {
         assertSame(executor, future.channel().pipeline().context(TestChannelHandler2.class).executor());
     }
 
-    private static final class TestChannelHandler extends ChannelHandlerAdapter {
+    private static final class TestChannelHandler extends ChannelDuplexHandler {
 
     }
 
-    private static final class TestChannelHandler2 extends ChannelHandlerAdapter {
+    private static final class TestChannelHandler2 extends ChannelDuplexHandler {
 
     }
 

transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java

@@ -16,6 +16,7 @@
 package io.netty.channel;
 
 
+import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Freeable;
 import io.netty.channel.ChannelHandler.Sharable;
 import io.netty.channel.local.LocalChannel;
@@ -24,10 +25,98 @@ import org.junit.Test;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.junit.Assert.*;
 
 public class DefaultChannelPipelineTest {
+    @Test
+    public void testMessageCatchAllInboundSink() throws Exception {
+        LocalChannel channel = new LocalChannel();
+        LocalEventLoopGroup group = new LocalEventLoopGroup();
+        group.register(channel).awaitUninterruptibly();
+        final AtomicBoolean forwarded = new AtomicBoolean();
+        final DefaultChannelPipeline pipeline = new DefaultChannelPipeline(channel);
+        pipeline.addLast(new ChannelInboundMessageHandlerAdapter<Object>() {
+            @Override
+            protected void messageReceived(ChannelHandlerContext ctx, Object msg) throws Exception {
+                forwarded.set(ctx.nextInboundMessageBuffer().add(msg));
+            }
+
+            @Override
+            protected void endMessageReceived(ChannelHandlerContext ctx) throws Exception {
+                ctx.fireInboundBufferUpdated();
+            }
+        });
+        channel.eventLoop().submit(new Runnable() {
+            @Override
+            public void run() {
+                pipeline.fireChannelActive();
+                pipeline.inboundMessageBuffer().add(new Object());
+                pipeline.fireInboundBufferUpdated();
+            }
+        }).get();
+
+        assertTrue(forwarded.get());
+    }
+
+    @Test
+    public void testByteCatchAllInboundSink() throws Exception {
+        LocalChannel channel = new LocalChannel();
+        LocalEventLoopGroup group = new LocalEventLoopGroup();
+        group.register(channel).awaitUninterruptibly();
+        final AtomicBoolean forwarded = new AtomicBoolean();
+        final DefaultChannelPipeline pipeline = new DefaultChannelPipeline(channel);
+        pipeline.addLast(new ChannelInboundByteHandlerAdapter() {
+            @Override
+            protected void inboundBufferUpdated(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
+                ByteBuf out = ctx.nextInboundByteBuffer();
+                out.writeBytes(in);
+                forwarded.set(true);
+                ctx.fireInboundBufferUpdated();
+            }
+        });
+        channel.eventLoop().submit(new Runnable() {
+            @Override
+            public void run() {
+                pipeline.fireChannelActive();
+                pipeline.inboundByteBuffer().writeByte(0);
+                pipeline.fireInboundBufferUpdated();
+            }
+        }).get();
+
+        assertTrue(forwarded.get());
+    }
+
+    @Test
+    public void testByteCatchAllOutboundSink() throws Exception {
+        LocalChannel channel = new LocalChannel();
+        LocalEventLoopGroup group = new LocalEventLoopGroup();
+        group.register(channel).awaitUninterruptibly();
+        final AtomicBoolean forwarded = new AtomicBoolean();
+        final DefaultChannelPipeline pipeline = new DefaultChannelPipeline(channel);
+        pipeline.addLast(new ChannelOutboundByteHandlerAdapter() {
+            @Override
+            protected void flush(ChannelHandlerContext ctx, ByteBuf in, ChannelPromise promise) throws Exception {
+                ByteBuf out = ctx.nextOutboundByteBuffer();
+                out.writeBytes(in);
+                forwarded.set(true);
+                ctx.flush(promise);
+            }
+        });
+        channel.eventLoop().submit(new Runnable() {
+            @Override
+            public void run() {
+                pipeline.fireChannelActive();
+                pipeline.outboundByteBuffer().writeByte(0);
+                pipeline.flush();
+            }
+        }).get();
+
+        Thread.sleep(1000);
+        assertTrue(forwarded.get());
+    }
+
     @Test
     public void testFreeCalled() throws InterruptedException{
         final CountDownLatch free = new CountDownLatch(1);
@@ -242,7 +331,7 @@ public class DefaultChannelPipelineTest {
     }
 
     @Sharable
-    private static class TestHandler extends ChannelHandlerAdapter {
+    private static class TestHandler extends ChannelDuplexHandler {
         // Dummy
     }
 }

transport/src/test/java/io/netty/channel/local/LocalTransportThreadModelTest.java

@@ -20,7 +20,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
-import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelInboundMessageHandler;
@@ -331,7 +331,7 @@ public class LocalTransportThreadModelTest {
     }
 
     private static class ThreadNameAuditor
-            extends ChannelHandlerAdapter
+            extends ChannelDuplexHandler
             implements ChannelInboundMessageHandler<Object>,
                        ChannelOutboundMessageHandler<Object> {
 
@@ -394,7 +394,7 @@ public class LocalTransportThreadModelTest {
      * Converts integers into a binary stream.
      */
     private static class MessageForwarder1
-            extends ChannelHandlerAdapter
+            extends ChannelDuplexHandler
             implements ChannelInboundMessageHandler<Integer>, ChannelOutboundByteHandler {
 
         private final AtomicReference<Throwable> exception = new AtomicReference<Throwable>();
@@ -502,7 +502,7 @@ public class LocalTransportThreadModelTest {
      * Converts a binary stream into integers.
      */
     private static class MessageForwarder2
-            extends ChannelHandlerAdapter
+            extends ChannelDuplexHandler
             implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<Integer> {
 
         private final AtomicReference<Throwable> exception = new AtomicReference<Throwable>();
@@ -605,7 +605,7 @@ public class LocalTransportThreadModelTest {
      * Simply forwards the received object to the next handler.
      */
     private static class MessageForwarder3
-            extends ChannelHandlerAdapter
+            extends ChannelDuplexHandler
             implements ChannelInboundMessageHandler<Object>, ChannelOutboundMessageHandler<Object> {
 
         private final AtomicReference<Throwable> exception = new AtomicReference<Throwable>();
@@ -695,7 +695,7 @@ public class LocalTransportThreadModelTest {
      * Discards all received messages.
      */
     private static class MessageDiscarder
-            extends ChannelHandlerAdapter
+            extends ChannelDuplexHandler
             implements ChannelInboundMessageHandler<Object>, ChannelOutboundMessageHandler<Object> {
 
         private final AtomicReference<Throwable> exception = new AtomicReference<Throwable>();