Replace TypeParameterFinder with TypeParameterMatcher

- We can avoid reflective matching using byte code generation.
 - Better matching performance when message type is Object

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

@@ -22,12 +22,12 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundByteHandler;
 import io.netty.channel.ChannelOutboundMessageHandler;
 import io.netty.channel.ChannelPromise;
-import io.netty.util.internal.TypeParameterFinder;
+import io.netty.util.internal.TypeParameterMatcher;
 
 public abstract class ByteToMessageCodec<I> extends ChannelDuplexHandler
         implements ChannelInboundByteHandler, ChannelOutboundMessageHandler<I> {
 
-    private final Class<?> acceptedOutboundMsgType;
+    private final TypeParameterMatcher outboundMsgMatcher;
     private final MessageToByteEncoder<I> encoder  = new MessageToByteEncoder<I>() {
         @Override
         public boolean acceptOutboundMessage(Object msg) throws Exception {
@@ -60,8 +60,7 @@ public abstract class ByteToMessageCodec<I> extends ChannelDuplexHandler
             @SuppressWarnings("rawtypes")
             Class<? extends ByteToMessageCodec> parameterizedHandlerType,
             int messageTypeParamIndex) {
-        acceptedOutboundMsgType =
+        outboundMsgMatcher = TypeParameterMatcher.find(this, parameterizedHandlerType, messageTypeParamIndex);
-                TypeParameterFinder.findActualTypeParameter(this, parameterizedHandlerType, messageTypeParamIndex);
     }
 
     @Override
@@ -105,7 +104,7 @@ public abstract class ByteToMessageCodec<I> extends ChannelDuplexHandler
     }
 
     public boolean acceptOutboundMessage(Object msg) throws Exception {
-        return acceptedOutboundMsgType.isInstance(msg);
+        return outboundMsgMatcher.match(msg);
     }
 
     protected abstract void encode(ChannelHandlerContext ctx, I msg, ByteBuf out) throws Exception;

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

@@ -24,7 +24,7 @@ import io.netty.channel.ChannelInboundMessageHandlerAdapter;
 import io.netty.channel.ChannelOutboundMessageHandler;
 import io.netty.channel.ChannelOutboundMessageHandlerAdapter;
 import io.netty.channel.ChannelPromise;
-import io.netty.util.internal.TypeParameterFinder;
+import io.netty.util.internal.TypeParameterMatcher;
 
 /**
  * A Codec for on-the-fly encoding/decoding of message.
@@ -97,12 +97,12 @@ public abstract class MessageToMessageCodec<INBOUND_IN, OUTBOUND_IN>
         }
     };
 
-    private final Class<?> acceptedInboundMsgType;
+    private final TypeParameterMatcher inboundMsgMatcher;
-    private final Class<?> acceptedOutboundMsgType;
+    private final TypeParameterMatcher outboundMsgMatcher;
 
     protected MessageToMessageCodec() {
-        acceptedInboundMsgType = TypeParameterFinder.findActualTypeParameter(this, MessageToMessageCodec.class, 0);
+        inboundMsgMatcher = TypeParameterMatcher.find(this, MessageToMessageCodec.class, 0);
-        acceptedOutboundMsgType = TypeParameterFinder.findActualTypeParameter(this, MessageToMessageCodec.class, 1);
+        outboundMsgMatcher = TypeParameterMatcher.find(this, MessageToMessageCodec.class, 1);
     }
 
     protected MessageToMessageCodec(
@@ -113,9 +113,9 @@ public abstract class MessageToMessageCodec<INBOUND_IN, OUTBOUND_IN>
             Class<? extends ChannelOutboundMessageHandlerAdapter> parameterizedOutboundHandlerType,
             int outboundMessageTypeParamIndex) {
 
-        acceptedInboundMsgType = TypeParameterFinder.findActualTypeParameter(
+        inboundMsgMatcher = TypeParameterMatcher.find(
                 this, parameterizedInboundHandlerType, inboundMessageTypeParamIndex);
-        acceptedOutboundMsgType = TypeParameterFinder.findActualTypeParameter(
+        outboundMsgMatcher = TypeParameterMatcher.find(
                 this, parameterizedOutboundHandlerType, outboundMessageTypeParamIndex);
     }
 
@@ -158,7 +158,7 @@ public abstract class MessageToMessageCodec<INBOUND_IN, OUTBOUND_IN>
      * @param msg the message
      */
     public boolean acceptInboundMessage(Object msg) throws Exception {
-        return acceptedInboundMsgType.isInstance(msg);
+        return inboundMsgMatcher.match(msg);
     }
 
     /**
@@ -167,7 +167,7 @@ public abstract class MessageToMessageCodec<INBOUND_IN, OUTBOUND_IN>
      * @param msg the message
      */
     public boolean acceptOutboundMessage(Object msg) throws Exception {
-        return acceptedOutboundMsgType.isInstance(msg);
+        return outboundMsgMatcher.match(msg);
     }
 
     protected abstract Object encode(ChannelHandlerContext ctx, OUTBOUND_IN msg) throws Exception;

common/src/main/java/io/netty/util/internal/TypeParameterMatcher.java

@@ -21,21 +21,31 @@ import java.lang.reflect.Type;
 import java.util.IdentityHashMap;
 import java.util.Map;
 
-public final class TypeParameterFinder {
+public abstract class TypeParameterMatcher {
 
-    private static final ThreadLocal<Map<Class<?>, Class<?>>> typeMap = new ThreadLocal<Map<Class<?>, Class<?>>>() {
+    private static final TypeParameterMatcher NOOP = new TypeParameterMatcher() {
         @Override
-        protected Map<Class<?>, Class<?>> initialValue() {
+        public boolean match(Object msg) {
-            return new IdentityHashMap<Class<?>, Class<?>>();
+            return true;
         }
     };
 
-    public static Class<?> findActualTypeParameter(
+    private static final ThreadLocal<Map<Class<?>, TypeParameterMatcher>> typeMap =
+            new ThreadLocal<Map<Class<?>, TypeParameterMatcher>>() {
+                @Override
+                protected Map<Class<?>, TypeParameterMatcher> initialValue() {
+                    return new IdentityHashMap<Class<?>, TypeParameterMatcher>();
+                }
+            };
+
+    public static TypeParameterMatcher find(
             final Object object, final Class<?> parameterizedSuperClass, final int typeParamIndex) {
-        final Map<Class<?>, Class<?>> typeMap = TypeParameterFinder.typeMap.get();
+
+        final Map<Class<?>, TypeParameterMatcher> typeMap = TypeParameterMatcher.typeMap.get();
         final Class<?> thisClass = object.getClass();
-        Class<?> messageType = typeMap.get(thisClass);
+
-        if (messageType == null) {
+        TypeParameterMatcher matcher = typeMap.get(thisClass);
+        if (matcher == null) {
             Class<?> currentClass = thisClass;
             for (;;) {
                 if (currentClass.getSuperclass() == parameterizedSuperClass) {
@@ -45,17 +55,37 @@ public final class TypeParameterFinder {
                                 "cannot determine the type of the type parameter of " + thisClass.getSimpleName());
                     }
 
-                    messageType = (Class<?>) types[0];
+                    Class<?> messageType = (Class<?>) types[0];
+                    if (messageType == Object.class) {
+                        matcher = NOOP;
+                    } else {
+                        matcher = new ReflectiveMatcher(messageType);
+                    }
                     break;
                 }
                 currentClass = currentClass.getSuperclass();
             }
 
-            typeMap.put(thisClass, messageType);
+            typeMap.put(thisClass, matcher);
         }
 
-        return messageType;
+        return matcher;
     }
 
-    private TypeParameterFinder() { }
+    public abstract boolean match(Object msg);
+
+    private static final class ReflectiveMatcher extends TypeParameterMatcher {
+        private final Class<?> type;
+
+        ReflectiveMatcher(Class<?> type) {
+            this.type = type;
+        }
+
+        @Override
+        public boolean match(Object msg) {
+            return type.isInstance(msg);
+        }
+    }
+
+    TypeParameterMatcher() { }
 }

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

@@ -17,7 +17,7 @@ package io.netty.channel;
 
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.util.internal.TypeParameterFinder;
+import io.netty.util.internal.TypeParameterMatcher;
 
 /**
  * {@link ChannelHandler} which handles inbound messages of a specific type.
@@ -44,7 +44,7 @@ import io.netty.util.internal.TypeParameterFinder;
 public abstract class ChannelInboundMessageHandlerAdapter<I>
         extends ChannelStateHandlerAdapter implements ChannelInboundMessageHandler<I> {
 
-    private final Class<?> acceptedMsgType;
+    private final TypeParameterMatcher msgMatcher;
 
     protected ChannelInboundMessageHandlerAdapter() {
         this(ChannelInboundMessageHandlerAdapter.class, 0);
@@ -54,8 +54,7 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
             @SuppressWarnings("rawtypes")
             Class<? extends ChannelInboundMessageHandlerAdapter> parameterizedHandlerType,
             int messageTypeParamIndex) {
-        acceptedMsgType = TypeParameterFinder.findActualTypeParameter(
+        msgMatcher = TypeParameterMatcher.find(this, parameterizedHandlerType, messageTypeParamIndex);
-                this, parameterizedHandlerType, messageTypeParamIndex);
     }
 
     @Override
@@ -126,7 +125,7 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
      * @param msg the message
      */
     public boolean acceptInboundMessage(Object msg) throws Exception {
-        return acceptedMsgType.isInstance(msg);
+        return msgMatcher.match(msg);
     }
 
     /**

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

@@ -17,7 +17,7 @@ package io.netty.channel;
 
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.util.internal.TypeParameterFinder;
+import io.netty.util.internal.TypeParameterMatcher;
 
 /**
  * Abstract base class which handles messages of a specific type.
@@ -27,7 +27,7 @@ import io.netty.util.internal.TypeParameterFinder;
 public abstract class ChannelOutboundMessageHandlerAdapter<I>
         extends ChannelOperationHandlerAdapter implements ChannelOutboundMessageHandler<I> {
 
-    private final Class<?> acceptedMsgType;
+    private final TypeParameterMatcher msgMatcher;
 
     protected ChannelOutboundMessageHandlerAdapter() {
         this(ChannelOutboundMessageHandlerAdapter.class, 0);
@@ -37,8 +37,7 @@ public abstract class ChannelOutboundMessageHandlerAdapter<I>
             @SuppressWarnings("rawtypes")
             Class<? extends ChannelOutboundMessageHandlerAdapter> parameterizedHandlerType,
             int messageTypeParamIndex) {
-        acceptedMsgType = TypeParameterFinder.findActualTypeParameter(
+        msgMatcher = TypeParameterMatcher.find(this, parameterizedHandlerType, messageTypeParamIndex);
-                this, parameterizedHandlerType, messageTypeParamIndex);
     }
 
     @Override
@@ -57,7 +56,7 @@ public abstract class ChannelOutboundMessageHandlerAdapter<I>
      * @param msg the message
      */
     public boolean acceptOutboundMessage(Object msg) throws Exception {
-        return acceptedMsgType.isInstance(msg);
+        return msgMatcher.match(msg);
     }
 
     @Override