Extract type parameter finder code to a utility class

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

@@ -0,0 +1,57 @@
+/*
+ * 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
+ * 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.util.internal;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+public final class TypeParameterFinder {
+
+    // TODO: Use a weak key map
+    private static final ConcurrentMap<Class<?>, Class<?>> typeMap = new ConcurrentHashMap<Class<?>, Class<?>>();
+
+    public static Class<?> findActualTypeParameter(
+            final Object object, final Class<?> parameterizedSuperClass, final int typeParamIndex) {
+        final Class<?> thisClass = object.getClass();
+        Class<?> messageType = typeMap.get(thisClass);
+        if (messageType == null) {
+            Class<?> currentClass = thisClass;
+            for (;;) {
+                if (currentClass.getSuperclass() == parameterizedSuperClass) {
+                    Type[] types = ((ParameterizedType) currentClass.getGenericSuperclass()).getActualTypeArguments();
+                    if (types.length - 1 < typeParamIndex || !(types[0] instanceof Class)) {
+                        throw new IllegalStateException(
+                                "cannot determine the inbound message type of " + thisClass.getSimpleName());
+                    }
+
+                    messageType = (Class<?>) types[0];
+                    break;
+                }
+                currentClass = currentClass.getSuperclass();
+            }
+
+            typeMap.put(thisClass, messageType);
+        }
+
+        return messageType;
+    }
+
+
+    private TypeParameterFinder() { }
+}

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

@@ -1,4 +1,4 @@
-io.netty.channel.DefaultChannelPromise.setFailure/*
+/*
  * Copyright 2012 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,

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

@@ -17,11 +17,7 @@ package io.netty.channel;
 
 import io.netty.buffer.MessageBuf;
 import io.netty.buffer.Unpooled;
-
+import io.netty.util.internal.TypeParameterFinder;
-import java.lang.reflect.ParameterizedType;
-import java.lang.reflect.Type;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentMap;
 
 /**
  * {@link ChannelHandler} which handles inbound messages of a specific type.
@@ -48,9 +44,6 @@ import java.util.concurrent.ConcurrentMap;
 public abstract class ChannelInboundMessageHandlerAdapter<I>
         extends ChannelStateHandlerAdapter implements ChannelInboundMessageHandler<I> {
 
-    private static final ConcurrentMap<Class<?>, Class<?>> messageTypeMap =
-            new ConcurrentHashMap<Class<?>, Class<?>>();
-
     private final Class<?> acceptedMsgType;
 
     protected ChannelInboundMessageHandlerAdapter() {
@@ -61,32 +54,8 @@ public abstract class ChannelInboundMessageHandlerAdapter<I>
             @SuppressWarnings("rawtypes")
             Class<? extends ChannelInboundMessageHandlerAdapter> parameterizedHandlerType,
             int messageTypeParamIndex) {
-        acceptedMsgType = findMessageType(parameterizedHandlerType, messageTypeParamIndex);
+        acceptedMsgType = TypeParameterFinder.findActualTypeParameter(
-    }
+                this, parameterizedHandlerType, messageTypeParamIndex);
-
-    private Class<?> findMessageType(Class<?> parameterizedHandlerType, int messageTypeParamIndex) {
-        final Class<?> thisClass = getClass();
-        Class<?> messageType = messageTypeMap.get(thisClass);
-        if (messageType == null) {
-            Class<?> currentClass = thisClass;
-            for (;;) {
-                if (currentClass.getSuperclass() == parameterizedHandlerType) {
-                    Type[] types = ((ParameterizedType) currentClass.getGenericSuperclass()).getActualTypeArguments();
-                    if (types.length - 1 < messageTypeParamIndex || !(types[0] instanceof Class)) {
-                        throw new IllegalStateException(
-                                "cannot determine the inbound message type of " + thisClass.getSimpleName());
-                    }
-
-                    messageType = (Class<?>) types[0];
-                    break;
-                }
-                currentClass = currentClass.getSuperclass();
-            }
-
-            messageTypeMap.put(thisClass, messageType);
-        }
-
-        return messageType;
     }
 
     @Override