* Added OneToOneEncoder and OneToOneDecoder

* Removed most duplicate code by extending them

src/main/java/org/jboss/netty/handler/codec/http/HttpMessageEncoder.java

@@ -21,7 +21,6 @@
  */
 package org.jboss.netty.handler.codec.http;
 
-import static org.jboss.netty.channel.Channels.*;
 import static org.jboss.netty.handler.codec.http.HttpCodecUtil.*;
 
 import java.util.List;
@@ -29,10 +28,10 @@ import java.util.Set;
 
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelHandlerContext;
 import org.jboss.netty.channel.ChannelPipelineCoverage;
-import org.jboss.netty.channel.MessageEvent;
-import org.jboss.netty.channel.SimpleChannelHandler;
+import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
 
 /**
  * encodes an http message
@@ -43,23 +42,23 @@ import org.jboss.netty.channel.SimpleChannelHandler;
  * @version $Rev$, $Date$
  */
 @ChannelPipelineCoverage("one")
-public abstract class HttpMessageEncoder extends SimpleChannelHandler {
+public abstract class HttpMessageEncoder extends OneToOneEncoder {
+
     @Override
-    public void writeRequested(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
-        if (!(e.getMessage() instanceof HttpMessage)) {
-            ctx.sendDownstream(e);
-            return;
+    protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
+        if (!(msg instanceof HttpMessage)) {
+            return msg;
         }
-        HttpMessage request = (HttpMessage) e.getMessage();
+        HttpMessage request = (HttpMessage) msg;
         ChannelBuffer buf = ChannelBuffers.dynamicBuffer(
-                e.getChannel().getConfig().getBufferFactory());
+                channel.getConfig().getBufferFactory());
         encodeInitialLine(buf, request);
         encodeHeaders(buf, request);
         buf.writeBytes(CRLF);
         if (request.getContent() != null) {
             buf.writeBytes(request.getContent());
         }
-        write(ctx, e.getChannel(), e.getFuture(), buf, e.getRemoteAddress());
+        return buf;
     }
 
     /**

src/main/java/org/jboss/netty/handler/codec/oneone/OneToOneDecoder.java

@@ -0,0 +1,85 @@
+/*
+ * JBoss, Home of Professional Open Source
+ *
+ * Copyright 2008, Red Hat Middleware LLC, and individual contributors
+ * by the @author tags. See the COPYRIGHT.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.jboss.netty.handler.codec.oneone;
+
+import static org.jboss.netty.channel.Channels.*;
+
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelPipeline;
+import org.jboss.netty.channel.ChannelUpstreamHandler;
+import org.jboss.netty.channel.MessageEvent;
+import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
+import org.jboss.netty.handler.codec.frame.Delimiters;
+import org.jboss.netty.handler.codec.frame.FrameDecoder;
+
+/**
+ * Transforms a received message into another message.  Please note that this
+ * decoder must be used with a proper {@link FrameDecoder} such as
+ * {@link DelimiterBasedFrameDecoder} if you are using a stream-based transport
+ * such as TCP/IP.  A typical decoder setup would be:
+ * <pre>
+ * {@link ChannelPipeline} pipeline = ...;
+ *
+ * // Decoders
+ * pipeline.addLast("frameDecoder", new {@link DelimiterBasedFrameDecoder}(80, {@link Delimiters#nulDelimiter()}));
+ * pipeline.addLast("customDecoder", new {@link OneToOneDecoder}() { ... });
+ *
+ * // Encoder
+ * pipeline.addLast("customEncoder", new {@link OneToOneEncoder}() { ... });
+ * </pre>
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ *
+ * @version $Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $
+ *
+ * @apiviz.landmark
+ */
+public abstract class OneToOneDecoder implements ChannelUpstreamHandler {
+
+    /**
+     * Creates a new instance with the current system character set.
+     */
+    protected OneToOneDecoder() {
+        super();
+    }
+
+    public void handleUpstream(
+            ChannelHandlerContext ctx, ChannelEvent evt) throws Exception {
+        if (!(evt instanceof MessageEvent)) {
+            ctx.sendUpstream(evt);
+            return;
+        }
+
+        MessageEvent e = (MessageEvent) evt;
+        fireMessageReceived(
+                ctx, e.getChannel(),
+                decode(ctx, e.getChannel(), e.getMessage()),
+                e.getRemoteAddress());
+    }
+
+    protected abstract Object decode(
+            ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception;
+}

src/main/java/org/jboss/netty/handler/codec/oneone/OneToOneEncoder.java

@@ -0,0 +1,78 @@
+/*
+ * JBoss, Home of Professional Open Source
+ *
+ * Copyright 2008, Red Hat Middleware LLC, and individual contributors
+ * by the @author tags. See the COPYRIGHT.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.jboss.netty.handler.codec.oneone;
+
+import static org.jboss.netty.channel.Channels.*;
+
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelDownstreamHandler;
+import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelPipeline;
+import org.jboss.netty.channel.MessageEvent;
+import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
+import org.jboss.netty.handler.codec.frame.Delimiters;
+
+/**
+ * Transforms a received message into another message.  A typical decoder setup
+ * would be:
+ * <pre>
+ * {@link ChannelPipeline} pipeline = ...;
+ *
+ * // Decoders
+ * pipeline.addLast("frameDecoder", new {@link DelimiterBasedFrameDecoder}(80, {@link Delimiters#nulDelimiter()}));
+ * pipeline.addLast("customDecoder", new {@link OneToOneDecoder}() { ... });
+ *
+ * // Encoder
+ * pipeline.addLast("customEncoder", new {@link OneToOneEncoder}() { ... });
+ * </pre>
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ *
+ * @version $Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $
+ *
+ * @apiviz.landmark
+ */
+public abstract class OneToOneEncoder implements ChannelDownstreamHandler {
+
+    protected OneToOneEncoder() {
+        super();
+    }
+
+    public void handleDownstream(
+            ChannelHandlerContext ctx, ChannelEvent evt) throws Exception {
+        if (!(evt instanceof MessageEvent)) {
+            ctx.sendDownstream(evt);
+            return;
+        }
+
+        MessageEvent e = (MessageEvent) evt;
+        write(ctx, e.getChannel(), e.getFuture(),
+              encode(ctx, e.getChannel(), e.getMessage()),
+              e.getRemoteAddress());
+    }
+
+    protected abstract Object encode(
+            ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception;
+}

src/main/java/org/jboss/netty/handler/codec/oneone/package-info.java

@@ -0,0 +1,28 @@
+/*
+ * JBoss, Home of Professional Open Source
+ *
+ * Copyright 2008, Red Hat Middleware LLC, and individual contributors
+ * by the @author tags. See the COPYRIGHT.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+
+/**
+ * Simplistic abstract classes which help implement encoder and decoder that
+ * transform an object into another object and vice versa.
+ */
+package org.jboss.netty.handler.codec.oneone;

src/main/java/org/jboss/netty/handler/codec/serialization/CompatibleObjectEncoder.java

@@ -22,8 +22,6 @@
  */
 package org.jboss.netty.handler.codec.serialization;
 
-import static org.jboss.netty.channel.Channels.*;
-
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.OutputStream;
@@ -33,11 +31,10 @@ import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBufferFactory;
 import org.jboss.netty.buffer.ChannelBufferOutputStream;
 import org.jboss.netty.buffer.ChannelBuffers;
-import org.jboss.netty.channel.ChannelDownstreamHandler;
-import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelHandlerContext;
 import org.jboss.netty.channel.ChannelPipelineCoverage;
-import org.jboss.netty.channel.MessageEvent;
+import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
 
 /**
  * An encoder which serializes a Java object into a {@link ChannelBuffer}
@@ -52,7 +49,7 @@ import org.jboss.netty.channel.MessageEvent;
  * @version $Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $
  */
 @ChannelPipelineCoverage("one")
-public class CompatibleObjectEncoder implements ChannelDownstreamHandler {
+public class CompatibleObjectEncoder extends OneToOneEncoder {
 
     private final AtomicReference<ChannelBuffer> buffer =
         new AtomicReference<ChannelBuffer>();
@@ -93,14 +90,8 @@ public class CompatibleObjectEncoder implements ChannelDownstreamHandler {
         return new ObjectOutputStream(out);
     }
 
-    public void handleDownstream(
-            ChannelHandlerContext context, ChannelEvent evt) throws Exception {
-        if (!(evt instanceof MessageEvent)) {
-            context.sendDownstream(evt);
-            return;
-        }
-
-        MessageEvent e = (MessageEvent) evt;
+    @Override
+    protected Object encode(ChannelHandlerContext context, Channel channel, Object msg) throws Exception {
         ChannelBuffer buffer = buffer(context);
         ObjectOutputStream oout = this.oout;
         if (resetInterval != 0) {
@@ -113,11 +104,11 @@ public class CompatibleObjectEncoder implements ChannelDownstreamHandler {
                 buffer.discardReadBytes();
             }
         }
-        oout.writeObject(e.getMessage());
+        oout.writeObject(msg);
         oout.flush();
 
         ChannelBuffer encoded = buffer.readBytes(buffer.readableBytes());
-        write(context, e.getChannel(), e.getFuture(), encoded, e.getRemoteAddress());
+        return encoded;
     }
 
     private ChannelBuffer buffer(ChannelHandlerContext ctx) throws Exception {

src/main/java/org/jboss/netty/handler/codec/serialization/ObjectEncoder.java

@@ -23,18 +23,16 @@
 package org.jboss.netty.handler.codec.serialization;
 
 import static org.jboss.netty.buffer.ChannelBuffers.*;
-import static org.jboss.netty.channel.Channels.*;
 
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBufferOutputStream;
-import org.jboss.netty.channel.ChannelDownstreamHandler;
-import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelHandlerContext;
 import org.jboss.netty.channel.ChannelPipelineCoverage;
-import org.jboss.netty.channel.MessageEvent;
+import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
 
 /**
  * An encoder which serializes a Java object into a {@link ChannelBuffer}.
@@ -57,7 +55,7 @@ import org.jboss.netty.channel.MessageEvent;
  * @apiviz.landmark
  */
 @ChannelPipelineCoverage("all")
-public class ObjectEncoder implements ChannelDownstreamHandler {
+public class ObjectEncoder extends OneToOneEncoder {
     private static final byte[] LENGTH_PLACEHOLDER = new byte[4];
 
     private final int estimatedLength;
@@ -88,26 +86,19 @@ public class ObjectEncoder implements ChannelDownstreamHandler {
         this.estimatedLength = estimatedLength;
     }
 
-    public void handleDownstream(
-            ChannelHandlerContext context, ChannelEvent evt) throws Exception {
-        if (!(evt instanceof MessageEvent)) {
-            context.sendDownstream(evt);
-            return;
-        }
-
-        MessageEvent e = (MessageEvent) evt;
+    @Override
+    protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
         ChannelBufferOutputStream bout =
             new ChannelBufferOutputStream(dynamicBuffer(
-                    estimatedLength, e.getChannel().getConfig().getBufferFactory()));
+                    estimatedLength, ctx.getChannel().getConfig().getBufferFactory()));
         bout.write(LENGTH_PLACEHOLDER);
         ObjectOutputStream oout = new CompactObjectOutputStream(bout);
-        oout.writeObject(e.getMessage());
+        oout.writeObject(msg);
         oout.flush();
         oout.close();
 
-        ChannelBuffer msg = bout.buffer();
-        msg.setInt(0, msg.writerIndex() - 4);
-
-        write(context, e.getChannel(), e.getFuture(), msg, e.getRemoteAddress());
+        ChannelBuffer encoded = bout.buffer();
+        encoded.setInt(0, encoded.writerIndex() - 4);
+        return encoded;
     }
 }

src/main/java/org/jboss/netty/handler/codec/string/StringDecoder.java

@@ -22,20 +22,17 @@
  */
 package org.jboss.netty.handler.codec.string;
 
-import static org.jboss.netty.channel.Channels.*;
-
 import java.nio.charset.Charset;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelHandlerContext;
 import org.jboss.netty.channel.ChannelPipeline;
 import org.jboss.netty.channel.ChannelPipelineCoverage;
-import org.jboss.netty.channel.ChannelUpstreamHandler;
-import org.jboss.netty.channel.MessageEvent;
 import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
 import org.jboss.netty.handler.codec.frame.Delimiters;
 import org.jboss.netty.handler.codec.frame.FrameDecoder;
+import org.jboss.netty.handler.codec.oneone.OneToOneDecoder;
 
 /**
  * Decodes a received {@link ChannelBuffer} into a {@link String}.  Please
@@ -70,7 +67,7 @@ import org.jboss.netty.handler.codec.frame.FrameDecoder;
  * @apiviz.landmark
  */
 @ChannelPipelineCoverage("all")
-public class StringDecoder implements ChannelUpstreamHandler {
+public class StringDecoder extends OneToOneDecoder {
 
     private final String charsetName;
 
@@ -102,21 +99,12 @@ public class StringDecoder implements ChannelUpstreamHandler {
         charsetName = charset.name();
     }
 
-    public void handleUpstream(
-            ChannelHandlerContext context, ChannelEvent evt) throws Exception {
-        if (!(evt instanceof MessageEvent)) {
-            context.sendUpstream(evt);
-            return;
+    @Override
+    public Object decode(
+            ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
+        if (!(msg instanceof ChannelBuffer)) {
+            return msg;
         }
-
-        MessageEvent e = (MessageEvent) evt;
-        if (!(e.getMessage() instanceof ChannelBuffer)) {
-            context.sendUpstream(evt);
-            return;
-        }
-
-        fireMessageReceived(
-                context, e.getChannel(),
-                ((ChannelBuffer) e.getMessage()).toString(charsetName));
+        return ((ChannelBuffer) msg).toString(charsetName);
     }
 }

src/main/java/org/jboss/netty/handler/codec/string/StringEncoder.java

@@ -23,19 +23,17 @@
 package org.jboss.netty.handler.codec.string;
 
 import static org.jboss.netty.buffer.ChannelBuffers.*;
-import static org.jboss.netty.channel.Channels.*;
 
 import java.nio.charset.Charset;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.jboss.netty.channel.ChannelDownstreamHandler;
-import org.jboss.netty.channel.ChannelEvent;
+import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelHandlerContext;
 import org.jboss.netty.channel.ChannelPipeline;
 import org.jboss.netty.channel.ChannelPipelineCoverage;
-import org.jboss.netty.channel.MessageEvent;
 import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
 import org.jboss.netty.handler.codec.frame.Delimiters;
+import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
 
 /**
  * Encodes the requested {@link String} into a {@link ChannelBuffer}.
@@ -68,7 +66,7 @@ import org.jboss.netty.handler.codec.frame.Delimiters;
  * @apiviz.landmark
  */
 @ChannelPipelineCoverage("all")
-public class StringEncoder implements ChannelDownstreamHandler {
+public class StringEncoder extends OneToOneEncoder {
 
     private final String charsetName;
 
@@ -87,20 +85,12 @@ public class StringEncoder implements ChannelDownstreamHandler {
         charsetName = charset.name();
     }
 
-    public void handleDownstream(
-            ChannelHandlerContext context, ChannelEvent evt) throws Exception {
-        if (!(evt instanceof MessageEvent)) {
-            context.sendDownstream(evt);
-            return;
+    @Override
+    protected Object encode(
+            ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
+        if (!(msg instanceof String)) {
+            return msg;
         }
-
-        MessageEvent e = (MessageEvent) evt;
-        if (!(e.getMessage() instanceof String)) {
-            context.sendDownstream(evt);
-            return;
-        }
-
-        write(context, e.getChannel(), e.getFuture(),
-                copiedBuffer(String.valueOf(e.getMessage()), charsetName));
+        return copiedBuffer(String.valueOf(msg), charsetName);
     }
 }