Change ReferenceCounted.retain* to return itself and so allow method chaining

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

@@ -28,10 +28,14 @@ public abstract class AbstractDerivedByteBuf extends AbstractByteBuf {
     }
 
     @Override
-    public final void retain() { }
+    public final ByteBuf retain() {
+        return this;
+    }
 
     @Override
-    public final void retain(int increment) { }
+    public final ByteBuf retain(int increment) {
+        return this;
+    }
 
     @Override
     public final boolean release() {

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

@@ -42,7 +42,7 @@ public abstract class AbstractMessageBuf<T> extends AbstractQueue<T> implements
     }
 
     @Override
-    public final void retain() {
+    public final MessageBuf<T> retain() {
         int refCnt = this.refCnt;
         if (refCnt <= 0) {
             throw new IllegalBufferAccessException();
@@ -53,10 +53,11 @@ public abstract class AbstractMessageBuf<T> extends AbstractQueue<T> implements
         }
 
         this.refCnt = refCnt + 1;
+        return this;
     }
 
     @Override
-    public final void retain(int increment) {
+    public final MessageBuf<T> retain(int increment) {
         if (increment <= 0) {
             throw new IllegalArgumentException("increment: " + increment + " (expected: > 0)");
         }
@@ -71,6 +72,7 @@ public abstract class AbstractMessageBuf<T> extends AbstractQueue<T> implements
         }
 
         this.refCnt = refCnt + 1;
+        return this;
     }
 
     @Override

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

@@ -31,7 +31,7 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
     }
 
     @Override
-    public final void retain() {
+    public ReferenceCounted retain() {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
@@ -44,10 +44,11 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
                 break;
             }
         }
+        return this;
     }
 
     @Override
-    public final void retain(int increment) {
+    public ReferenceCounted retain(int increment) {
         if (increment <= 0) {
             throw new IllegalArgumentException("increment: " + increment + " (expected: > 0)");
         }
@@ -64,6 +65,7 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
                 break;
             }
         }
+        return this;
     }
 
     @Override

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

@@ -36,7 +36,7 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
     }
 
     @Override
-    public final void retain() {
+    public ByteBuf retain() {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
@@ -49,10 +49,11 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
                 break;
             }
         }
+        return this;
     }
 
     @Override
-    public final void retain(int increment) {
+    public ByteBuf retain(int increment) {
         if (increment <= 0) {
             throw new IllegalArgumentException("increment: " + increment + " (expected: > 0)");
         }
@@ -69,6 +70,7 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
                 break;
             }
         }
+        return this;
     }
 
     @Override

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

@@ -49,4 +49,10 @@ public interface Buf extends ReferenceCounted {
      * elements.
      */
     boolean isWritable(int size);
+
+    @Override
+    Buf retain();
+
+    @Override
+    Buf retain(int increment);
 }

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

@@ -1915,4 +1915,10 @@ public interface ByteBuf extends Buf, Comparable<ByteBuf> {
      */
     @Override
     String toString();
+
+    @Override
+    ByteBuf retain(int increment);
+
+    @Override
+    ByteBuf retain();
 }

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

@@ -30,4 +30,10 @@ public interface ByteBufHolder extends ReferenceCounted {
      * Create a deep copy of this {@link ByteBufHolder}.
      */
     ByteBufHolder copy();
+
+    @Override
+    ByteBufHolder retain();
+
+    @Override
+    ByteBufHolder retain(int increment);
 }

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

@@ -374,4 +374,10 @@ public interface CompositeByteBuf extends ByteBuf, Iterable<ByteBuf> {
 
     @Override
     CompositeByteBuf resumeIntermediaryDeallocations();
+
+    @Override
+    CompositeByteBuf retain(int increment);
+
+    @Override
+    CompositeByteBuf retain();
 }

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

@@ -53,13 +53,15 @@ public class DefaultByteBufHolder implements ByteBufHolder {
     }
 
     @Override
-    public void retain() {
+    public ByteBufHolder retain() {
         data.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public ByteBufHolder retain(int increment) {
         data.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -40,7 +40,8 @@ import java.util.Queue;
  * is recommended to use {@link Unpooled#wrappedBuffer(ByteBuf...)}
  * instead of calling the constructor explicitly.
  */
-public class DefaultCompositeByteBuf extends AbstractReferenceCountedByteBuf implements CompositeByteBuf {
+public class DefaultCompositeByteBuf extends AbstractReferenceCountedByteBuf
+        implements CompositeByteBuf {
 
     private static final ByteBuffer[] EMPTY_NIOBUFFERS = new ByteBuffer[0];
 
@@ -1514,6 +1515,16 @@ public class DefaultCompositeByteBuf extends AbstractReferenceCountedByteBuf imp
         return (CompositeByteBuf) super.writeZero(length);
     }
 
+    @Override
+    public CompositeByteBuf retain(int increment) {
+        return (CompositeByteBuf) super.retain(increment);
+    }
+
+    @Override
+    public CompositeByteBuf retain() {
+        return (CompositeByteBuf) super.retain();
+    }
+
     @Override
     public ByteBuffer[] nioBuffers() {
         return nioBuffers(readerIndex(), readableBytes());

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

@@ -809,10 +809,14 @@ public final class EmptyByteBuf implements ByteBuf {
     }
 
     @Override
-    public void retain() { }
+    public ByteBuf retain() {
+        return this;
+    }
 
     @Override
-    public void retain(int increment) { }
+    public ByteBuf retain(int increment) {
+        return this;
+    }
 
     @Override
     public boolean release() {

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

@@ -205,13 +205,15 @@ public abstract class FilteredMessageBuf implements MessageBuf<Object> {
     }
 
     @Override
-    public void retain() {
+    public MessageBuf<Object> retain() {
         buf.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public MessageBuf<Object> retain(int increment) {
         buf.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -54,4 +54,10 @@ public interface MessageBuf<T> extends Buf, Queue<T> {
      * @return number       the number of objects which was transfered
      */
     int drainTo(Collection<? super T> c, int maxElements);
+
+    @Override
+    MessageBuf<T> retain(int increment);
+
+    @Override
+    MessageBuf<T> retain();
 }

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

@@ -37,12 +37,12 @@ public interface ReferenceCounted {
     /**
      * Increases the reference count by {@code 1}.
      */
-    void retain();
+    ReferenceCounted retain();
 
     /**
      * Increases the reference count by the specified {@code increment}.
      */
-    void retain(int increment);
+    ReferenceCounted retain(int increment);
 
     /**
      * Decreases the reference count by {@code 1} and deallocates this object if the reference count reaches at

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

@@ -821,13 +821,15 @@ public final class SwappedByteBuf implements ByteBuf {
     }
 
     @Override
-    public void retain() {
+    public ByteBuf retain() {
         buf.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public ByteBuf retain(int increment) {
         buf.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -53,13 +53,15 @@ public class DefaultFullHttpRequest extends DefaultHttpRequest implements FullHt
     }
 
     @Override
-    public void retain() {
+    public FullHttpRequest retain() {
         content.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public FullHttpRequest retain(int increment) {
         content.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -55,13 +55,15 @@ public class DefaultFullHttpResponse extends DefaultHttpResponse implements Full
     }
 
     @Override
-    public void retain() {
+    public FullHttpResponse retain() {
         content.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public FullHttpResponse retain(int increment) {
         content.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -50,13 +50,15 @@ public class DefaultHttpContent extends DefaultHttpObject implements HttpContent
     }
 
     @Override
-    public void retain() {
+    public HttpContent retain() {
         content.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public HttpContent retain(int increment) {
         content.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -54,6 +54,18 @@ public class DefaultLastHttpContent extends DefaultHttpContent implements LastHt
         return copy;
     }
 
+    @Override
+    public LastHttpContent retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
+
+    @Override
+    public LastHttpContent retain() {
+        super.retain();
+        return this;
+    }
+
     @Override
     public HttpHeaders trailingHeaders() {
         return trailingHeaders;

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

@@ -23,4 +23,9 @@ public interface FullHttpMessage extends HttpMessage, LastHttpContent {
     @Override
     FullHttpMessage copy();
 
+    @Override
+    FullHttpMessage retain(int increment);
+
+    @Override
+    FullHttpMessage retain();
 }

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

@@ -23,6 +23,12 @@ public interface FullHttpRequest extends HttpRequest, FullHttpMessage {
     @Override
     FullHttpRequest copy();
 
+    @Override
+    FullHttpRequest retain(int increment);
+
+    @Override
+    FullHttpRequest retain();
+
     @Override
     FullHttpRequest setProtocolVersion(HttpVersion version);
 

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

@@ -23,6 +23,12 @@ public interface FullHttpResponse extends HttpResponse, FullHttpMessage {
     @Override
     FullHttpResponse copy();
 
+    @Override
+    FullHttpResponse retain(int increment);
+
+    @Override
+    FullHttpResponse retain();
+
     @Override
     FullHttpResponse setProtocolVersion(HttpVersion version);
 

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

@@ -30,4 +30,10 @@ import io.netty.channel.ChannelPipeline;
 public interface HttpContent extends HttpObject, ByteBufHolder {
     @Override
     HttpContent copy();
+
+    @Override
+    HttpContent retain();
+
+    @Override
+    HttpContent retain(int increment);
 }

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

@@ -129,12 +129,10 @@ public abstract class HttpContentEncoder extends MessageToMessageCodec<HttpMessa
                 Result result = beginEncode(message, c, acceptEncoding);
 
                 if (result == null) {
-                    ByteBuf data = c.data();
-                    data.retain();
                     if (c instanceof LastHttpContent) {
-                        return new Object[] { message, new DefaultLastHttpContent(data) };
+                        return new Object[] { message, new DefaultLastHttpContent(c.data().retain()) };
                     } else {
-                        return new Object[] { message, new DefaultHttpContent(data) };
+                        return new Object[] { message, new DefaultHttpContent(c.data().retain()) };
                     }
                 }
 

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

@@ -60,10 +60,14 @@ public interface LastHttpContent extends HttpContent {
         }
 
         @Override
-        public void retain() { }
+        public LastHttpContent retain() {
+            return this;
+        }
 
         @Override
-        public void retain(int increment) { }
+        public LastHttpContent retain(int increment) {
+            return this;
+        }
 
         @Override
         public boolean release() {
@@ -80,4 +84,10 @@ public interface LastHttpContent extends HttpContent {
 
     @Override
     LastHttpContent copy();
+
+    @Override
+    LastHttpContent retain(int increment);
+
+    @Override
+    LastHttpContent retain();
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractHttpData.java

@@ -114,4 +114,16 @@ public abstract class AbstractHttpData extends AbstractReferenceCounted implemen
     protected void deallocate() {
         delete();
     }
+
+    @Override
+    public HttpData retain() {
+        super.retain();
+        return this;
+    }
+
+    @Override
+    public HttpData retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/Attribute.java

@@ -33,4 +33,10 @@ public interface Attribute extends HttpData {
 
     @Override
     Attribute copy();
+
+    @Override
+    Attribute retain();
+
+    @Override
+    Attribute retain(int increment);
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/DiskAttribute.java

@@ -141,7 +141,7 @@ public class DiskAttribute extends AbstractDiskHttpData implements Attribute {
     }
 
     @Override
-    public DiskAttribute copy() {
+    public Attribute copy() {
         DiskAttribute attr = new DiskAttribute(getName());
         attr.setCharset(getCharset());
         ByteBuf content = data();
@@ -154,4 +154,16 @@ public class DiskAttribute extends AbstractDiskHttpData implements Attribute {
         }
         return attr;
     }
+
+    @Override
+    public Attribute retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
+
+    @Override
+    public Attribute retain() {
+        super.retain();
+        return this;
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/DiskFileUpload.java

@@ -164,7 +164,7 @@ public class DiskFileUpload extends AbstractDiskHttpData implements FileUpload {
     }
 
     @Override
-    public DiskFileUpload copy() {
+    public FileUpload copy() {
         DiskFileUpload upload = new DiskFileUpload(getName(),
                 getFilename(), getContentType(), getContentTransferEncoding(), getCharset(), size);
         ByteBuf buf = data();
@@ -177,4 +177,16 @@ public class DiskFileUpload extends AbstractDiskHttpData implements FileUpload {
         }
         return upload;
     }
+
+    @Override
+    public FileUpload retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
+
+    @Override
+    public FileUpload retain() {
+        super.retain();
+        return this;
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/FileUpload.java

@@ -58,4 +58,10 @@ public interface FileUpload extends HttpData {
 
     @Override
     FileUpload copy();
+
+    @Override
+    FileUpload retain();
+
+    @Override
+    FileUpload retain(int increment);
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpData.java

@@ -179,4 +179,10 @@ public interface HttpData extends InterfaceHttpData, ByteBufHolder {
 
     @Override
     HttpData copy();
+
+    @Override
+    HttpData retain();
+
+    @Override
+    HttpData retain(int increment);
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/MemoryAttribute.java

@@ -102,7 +102,7 @@ public class MemoryAttribute extends AbstractMemoryHttpData implements Attribute
     }
 
     @Override
-    public MemoryAttribute copy() {
+    public Attribute copy() {
         MemoryAttribute attr = new MemoryAttribute(getName());
         attr.setCharset(getCharset());
         ByteBuf content = data();
@@ -115,4 +115,16 @@ public class MemoryAttribute extends AbstractMemoryHttpData implements Attribute
         }
         return attr;
     }
+
+    @Override
+    public Attribute retain() {
+        super.retain();
+        return this;
+    }
+
+    @Override
+    public Attribute retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/MemoryFileUpload.java

@@ -130,7 +130,7 @@ public class MemoryFileUpload extends AbstractMemoryHttpData implements FileUplo
     }
 
     @Override
-    public MemoryFileUpload copy() {
+    public FileUpload copy() {
         MemoryFileUpload upload = new MemoryFileUpload(getName(), getFilename(), getContentType(),
                 getContentTransferEncoding(), getCharset(), size);
         ByteBuf buf = data();
@@ -144,4 +144,16 @@ public class MemoryFileUpload extends AbstractMemoryHttpData implements FileUplo
         }
         return upload;
     }
+
+    @Override
+    public FileUpload retain() {
+        super.retain();
+        return this;
+    }
+
+    @Override
+    public FileUpload retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/multipart/MixedAttribute.java

@@ -215,13 +215,15 @@ public class MixedAttribute implements Attribute {
     }
 
     @Override
-    public void retain() {
+    public Attribute retain() {
         attribute.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public Attribute retain(int increment) {
         attribute.retain(increment);
+        return this;
     }
 
     @Override

codec-http/src/main/java/io/netty/handler/codec/http/multipart/MixedFileUpload.java

@@ -241,13 +241,15 @@ public class MixedFileUpload implements FileUpload {
     }
 
     @Override
-    public void retain() {
+    public FileUpload retain() {
         fileUpload.retain();
+        return this;
     }
 
     @Override
-    public void retain(int increment) {
+    public FileUpload retain(int increment) {
         fileUpload.retain(increment);
+        return this;
     }
 
     @Override

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

@@ -89,6 +89,18 @@ public class DefaultSpdyDataFrame extends DefaultByteBufHolder implements SpdyDa
         return frame;
     }
 
+    @Override
+    public SpdyDataFrame retain() {
+        super.retain();
+        return this;
+    }
+
+    @Override
+    public SpdyDataFrame retain(int increment) {
+        super.retain(increment);
+        return this;
+    }
+
     @Override
     public String toString() {
         StringBuilder buf = new StringBuilder();

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

@@ -41,4 +41,10 @@ public interface SpdyDataFrame extends ByteBufHolder, SpdyStreamFrame, SpdyDataO
 
     @Override
     SpdyDataFrame copy();
+
+    @Override
+    SpdyDataFrame retain();
+
+    @Override
+    SpdyDataFrame retain(int increment);
 }

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

@@ -884,12 +884,12 @@ final class ReplayingDecoderBuffer implements ByteBuf {
     }
 
     @Override
-    public void retain() {
+    public ByteBuf retain() {
         throw new UnreplayableOperationException();
     }
 
     @Override
-    public void retain(int increment) {
+    public ByteBuf retain(int increment) {
         throw new UnreplayableOperationException();
     }
 

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

@@ -128,13 +128,15 @@ public class DefaultChannelPipelineTest {
             }
 
             @Override
-            public void retain() {
+            public ReferenceCounted retain() {
                 fail();
+                return this;
             }
 
             @Override
-            public void retain(int increment) {
+            public ReferenceCounted retain(int increment) {
                 fail();
+                return this;
             }
 
             @Override