Resolved issue: NETTY-244 ReceiveBufferSizePredictorFactory

* Added ReceiveBufferSizePredictorFactory
* Added AdaptiveReceiveBufferSizePredictorFactory
* Added FixedReceiveBufferSizePredictorFactory
* Added get/setReceiveBufferSizePredictorFactory() to all related ChannelConfig interfaces and implementations
* More accurate documentation on the default predictors
* the default predictors are null internally and created lazily on demand to reduce footprint

src/main/java/org/jboss/netty/channel/AdaptiveReceiveBufferSizePredictor.java

@@ -37,8 +37,9 @@ import java.util.List;
 public class AdaptiveReceiveBufferSizePredictor implements
         ReceiveBufferSizePredictor {
 
-    // FIXME There's no easy way to configure receiveBufferSizePredictor
-    //       via Bootstrap.setOption() because it works for only one channel.
+    static final int DEFAULT_MINIMUM = 64;
+    static final int DEFAULT_INITIAL = 1024;
+    static final int DEFAULT_MAXIMUM = 65536;
 
     private static final int INDEX_INCREMENT = 4;
     private static final int INDEX_DECREMENT = 1;
@@ -97,10 +98,6 @@ public class AdaptiveReceiveBufferSizePredictor implements
         throw new Error("shouldn't reach here; please file a bug report.");
     }
 
-    private static final int DEFAULT_MINIMUM = 64;
-    private static final int DEFAULT_INITIAL = 1024;
-    private static final int DEFAULT_MAXIMUM = 65536;
-
     private final int minIndex;
     private final int maxIndex;
     private int index;

src/main/java/org/jboss/netty/channel/AdaptiveReceiveBufferSizePredictorFactory.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.channel;
+
+
+/**
+ * The {@link ReceiveBufferSizePredictorFactory} that creates a new
+ * {@link AdaptiveReceiveBufferSizePredictor}.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (trustin@gmail.com)
+ *
+ * @version $Rev$, $Date$
+ */
+public class AdaptiveReceiveBufferSizePredictorFactory implements
+        ReceiveBufferSizePredictorFactory {
+
+    private final int minimum;
+    private final int initial;
+    private final int maximum;
+
+    /**
+     * Creates a new factory with the default parameters.  With the default
+     * parameters, the expected buffer size starts from {@code 1024}, does not
+     * go down below {@code 64}, and does not go up above {@code 65536}.
+     */
+    public AdaptiveReceiveBufferSizePredictorFactory() {
+        this(AdaptiveReceiveBufferSizePredictor.DEFAULT_MINIMUM,
+                AdaptiveReceiveBufferSizePredictor.DEFAULT_INITIAL,
+                AdaptiveReceiveBufferSizePredictor.DEFAULT_MAXIMUM);
+    }
+
+    /**
+     * Creates a new factory with the specified parameters.
+     *
+     * @param minimum  the inclusive lower bound of the expected buffer size
+     * @param initial  the initial buffer size when no feed back was received
+     * @param maximum  the inclusive upper bound of the expected buffer size
+     */
+    public AdaptiveReceiveBufferSizePredictorFactory(int minimum, int initial, int maximum) {
+        if (minimum <= 0) {
+            throw new IllegalArgumentException("minimum: " + minimum);
+        }
+        if (initial < minimum) {
+            throw new IllegalArgumentException("initial: " + initial);
+        }
+        if (maximum < initial) {
+            throw new IllegalArgumentException("maximum: " + maximum);
+        }
+
+        this.minimum = minimum;
+        this.initial = initial;
+        this.maximum = maximum;
+    }
+
+    public ReceiveBufferSizePredictor getPredictor() throws Exception {
+        return new AdaptiveReceiveBufferSizePredictor(minimum, initial, maximum);
+    }
+}

src/main/java/org/jboss/netty/channel/FixedReceiveBufferSizePredictorFactory.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.channel;
+
+
+/**
+ * The {@link ReceiveBufferSizePredictorFactory} that returns a
+ * {@link FixedReceiveBufferSizePredictor} with the pre-defined configuration.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (trustin@gmail.com)
+ *
+ * @version $Rev$, $Date$
+ */
+public class FixedReceiveBufferSizePredictorFactory implements
+        ReceiveBufferSizePredictorFactory {
+
+    private final ReceiveBufferSizePredictor predictor;
+
+    /**
+     * Creates a new factory that returns a {@link FixedReceiveBufferSizePredictor}
+     * which always returns the same prediction of the specified buffer size.
+     */
+    public FixedReceiveBufferSizePredictorFactory(int bufferSize) {
+        predictor = new FixedReceiveBufferSizePredictor(bufferSize);
+    }
+
+    public ReceiveBufferSizePredictor getPredictor() throws Exception {
+        return predictor;
+    }
+}

src/main/java/org/jboss/netty/channel/ReceiveBufferSizePredictorFactory.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.channel;
+
+/**
+ * Creates a new {@link ReceiveBufferSizePredictor}.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (trustin@gmail.com)
+ *
+ * @version $Rev$, $Date$
+ */
+public interface ReceiveBufferSizePredictorFactory {
+
+    /**
+     * Returns a newly created {@link ReceiveBufferSizePredictor}.
+     */
+    ReceiveBufferSizePredictor getPredictor() throws Exception;
+}

src/main/java/org/jboss/netty/channel/socket/DatagramChannelConfig.java

@@ -21,7 +21,9 @@ import java.net.NetworkInterface;
 
 import org.jboss.netty.channel.ChannelConfig;
 import org.jboss.netty.channel.FixedReceiveBufferSizePredictor;
+import org.jboss.netty.channel.FixedReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 
 /**
  * A {@link ChannelConfig} for a {@link DatagramChannel}.
@@ -49,6 +51,8 @@ import org.jboss.netty.channel.ReceiveBufferSizePredictor;
  * </tr><tr>
  * <td>{@code "receiveBufferSizePredictor"}</td><td>{@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}</td>
  * </tr><tr>
+ * <td>{@code "receiveBufferSizePredictorFactory"}</td><td>{@link #setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory)}</td>
+ * </tr><tr>
  * <td>{@code "sendBufferSize"}</td><td>{@link #setSendBufferSize(int)}</td>
  * </tr><tr>
  * <td>{@code "timeToLive"}</td><td>{@link #setTimeToLive(int)}</td>
@@ -176,4 +180,24 @@ public interface DatagramChannelConfig extends ChannelConfig {
      * predictor is <tt>{@link FixedReceiveBufferSizePredictor}(768)</tt>.
      */
     void setReceiveBufferSizePredictor(ReceiveBufferSizePredictor predictor);
+
+    /**
+     * Returns the {@link ReceiveBufferSizePredictorFactory} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link FixedReceiveBufferSizePredictorFactory}(768)</tt>.
+     */
+    ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory();
+
+    /**
+     * Sets the {@link ReceiveBufferSizePredictor} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link FixedReceiveBufferSizePredictorFactory}(768)</tt>.
+     */
+    void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory);
 }

src/main/java/org/jboss/netty/channel/socket/DefaultDatagramChannelConfig.java

@@ -24,8 +24,9 @@ import java.net.SocketException;
 
 import org.jboss.netty.channel.ChannelException;
 import org.jboss.netty.channel.DefaultChannelConfig;
-import org.jboss.netty.channel.FixedReceiveBufferSizePredictor;
+import org.jboss.netty.channel.FixedReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 import org.jboss.netty.util.internal.ConversionUtil;
 
 /**
@@ -40,9 +41,12 @@ import org.jboss.netty.util.internal.ConversionUtil;
 public class DefaultDatagramChannelConfig extends DefaultChannelConfig
                                         implements DatagramChannelConfig {
 
+    private static final ReceiveBufferSizePredictorFactory DEFAULT_PREDICTOR_FACTORY =
+        new FixedReceiveBufferSizePredictorFactory(768);
+
     private final DatagramSocket socket;
-    private volatile ReceiveBufferSizePredictor predictor =
-        new FixedReceiveBufferSizePredictor(768);
+    private volatile ReceiveBufferSizePredictor predictor;
+    private volatile ReceiveBufferSizePredictorFactory predictorFactory = DEFAULT_PREDICTOR_FACTORY;
 
     /**
      * Creates a new instance.
@@ -263,13 +267,36 @@ public class DefaultDatagramChannelConfig extends DefaultChannelConfig
     }
 
     public ReceiveBufferSizePredictor getReceiveBufferSizePredictor() {
+        ReceiveBufferSizePredictor predictor = this.predictor;
+        if (predictor == null) {
+            try {
+                this.predictor = predictor = getReceiveBufferSizePredictorFactory().getPredictor();
+            } catch (Exception e) {
+                throw new ChannelException(
+                        "Failed to create a new " +
+                        ReceiveBufferSizePredictor.class.getSimpleName() + '.',
+                        e);
+            }
+        }
         return predictor;
     }
 
-    public void setReceiveBufferSizePredictor(ReceiveBufferSizePredictor predictor) {
+    public void setReceiveBufferSizePredictor(
+            ReceiveBufferSizePredictor predictor) {
         if (predictor == null) {
             throw new NullPointerException("predictor");
         }
         this.predictor = predictor;
     }
+
+    public ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory() {
+        return predictorFactory;
+    }
+
+    public void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory) {
+        if (predictorFactory == null) {
+            throw new NullPointerException("predictorFactory");
+        }
+        this.predictorFactory = predictorFactory;
+    }
 }

src/main/java/org/jboss/netty/channel/socket/nio/DefaultNioSocketChannelConfig.java

@@ -18,8 +18,10 @@ package org.jboss.netty.channel.socket.nio;
 import java.net.Socket;
 import java.util.Map;
 
-import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictor;
+import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictorFactory;
+import org.jboss.netty.channel.ChannelException;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.socket.DefaultSocketChannelConfig;
 import org.jboss.netty.logging.InternalLogger;
 import org.jboss.netty.logging.InternalLoggerFactory;
@@ -40,10 +42,13 @@ class DefaultNioSocketChannelConfig extends DefaultSocketChannelConfig
     private static final InternalLogger logger =
         InternalLoggerFactory.getInstance(DefaultNioSocketChannelConfig.class);
 
+    private static final ReceiveBufferSizePredictorFactory DEFAULT_PREDICTOR_FACTORY =
+        new AdaptiveReceiveBufferSizePredictorFactory();
+
     private volatile int writeBufferHighWaterMark = 64 * 1024;
     private volatile int writeBufferLowWaterMark  = 32 * 1024;
-    private volatile ReceiveBufferSizePredictor predictor =
-        new AdaptiveReceiveBufferSizePredictor();
+    private volatile ReceiveBufferSizePredictor predictor;
+    private volatile ReceiveBufferSizePredictorFactory predictorFactory = DEFAULT_PREDICTOR_FACTORY;
     private volatile int writeSpinCount = 16;
 
     DefaultNioSocketChannelConfig(Socket socket) {
@@ -143,6 +148,17 @@ class DefaultNioSocketChannelConfig extends DefaultSocketChannelConfig
     }
 
     public ReceiveBufferSizePredictor getReceiveBufferSizePredictor() {
+        ReceiveBufferSizePredictor predictor = this.predictor;
+        if (predictor == null) {
+            try {
+                this.predictor = predictor = getReceiveBufferSizePredictorFactory().getPredictor();
+            } catch (Exception e) {
+                throw new ChannelException(
+                        "Failed to create a new " +
+                        ReceiveBufferSizePredictor.class.getSimpleName() + '.',
+                        e);
+            }
+        }
         return predictor;
     }
 
@@ -154,6 +170,17 @@ class DefaultNioSocketChannelConfig extends DefaultSocketChannelConfig
         this.predictor = predictor;
     }
 
+    public ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory() {
+        return predictorFactory;
+    }
+
+    public void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory) {
+        if (predictorFactory == null) {
+            throw new NullPointerException("predictorFactory");
+        }
+        this.predictorFactory = predictorFactory;
+    }
+
     public boolean isReadWriteFair() {
         logger.warn(
                 "Detected an access to a deprecated configuration parameter: " +

src/main/java/org/jboss/netty/channel/socket/nio/NioDatagramChannelConfig.java

@@ -18,10 +18,8 @@ package org.jboss.netty.channel.socket.nio;
 import java.nio.ByteBuffer;
 import java.nio.channels.WritableByteChannel;
 
-import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictor;
 import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelConfig;
-import org.jboss.netty.channel.ReceiveBufferSizePredictor;
 import org.jboss.netty.channel.socket.DatagramChannel;
 import org.jboss.netty.channel.socket.DatagramChannelConfig;
 
@@ -44,8 +42,6 @@ import org.jboss.netty.channel.socket.DatagramChannelConfig;
  * </tr><tr>
  * <td>{@code "writeSpinCount"}</td><td>{@link #setWriteSpinCount(int)}</td>
  * </tr><tr>
- * <td>{@code "receiveBufferSizePredictor"}</td><td>{@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}</td>
- * </tr><tr>
  * </table>
  *
  * @author The Netty Project (netty-dev@lists.jboss.org)
@@ -108,18 +104,4 @@ public interface NioDatagramChannelConfig extends DatagramChannelConfig {
      *         if the specified value is {@code 0} or less than {@code 0}
      */
     void setWriteSpinCount(int writeSpinCount);
-
-    /**
-     * Returns the {@link ReceiveBufferSizePredictor} which predicts the
-     * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
-     */
-    ReceiveBufferSizePredictor getReceiveBufferSizePredictor();
-
-    /**
-     * Sets the {@link ReceiveBufferSizePredictor} which predicts the
-     * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
-     */
-    void setReceiveBufferSizePredictor(ReceiveBufferSizePredictor predictor);
 }

src/main/java/org/jboss/netty/channel/socket/nio/NioSocketChannelConfig.java

@@ -19,9 +19,11 @@ import java.nio.ByteBuffer;
 import java.nio.channels.WritableByteChannel;
 
 import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictor;
+import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.Channel;
 import org.jboss.netty.channel.ChannelConfig;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.socket.SocketChannel;
 import org.jboss.netty.channel.socket.SocketChannelConfig;
 
@@ -46,6 +48,8 @@ import org.jboss.netty.channel.socket.SocketChannelConfig;
  * </tr><tr>
  * <td>{@code "receiveBufferSizePredictor"}</td><td>{@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}</td>
  * </tr><tr>
+ * <td>{@code "receiveBufferSizePredictorFactory"}</td><td>{@link #setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory)}</td>
+ * </tr><tr>
  * <td>{@code "readWriteFair"}</td><td>{@link #setReadWriteFair(boolean)}</td>
  * </tr>
  * </table>
@@ -113,17 +117,37 @@ public interface NioSocketChannelConfig extends SocketChannelConfig {
     /**
      * Returns the {@link ReceiveBufferSizePredictor} which predicts the
      * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
+     * predictor is <tt>{@link AdaptiveReceiveBufferSizePredictor}(64, 1024, 65536)</tt>.
      */
     ReceiveBufferSizePredictor getReceiveBufferSizePredictor();
 
     /**
      * Sets the {@link ReceiveBufferSizePredictor} which predicts the
      * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
+     * predictor is <tt>{@link AdaptiveReceiveBufferSizePredictor}(64, 1024, 65536)</tt>.
      */
     void setReceiveBufferSizePredictor(ReceiveBufferSizePredictor predictor);
 
+    /**
+     * Returns the {@link ReceiveBufferSizePredictorFactory} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link AdaptiveReceiveBufferSizePredictorFactory}(64, 1024, 65536)</tt>.
+     */
+    ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory();
+
+    /**
+     * Sets the {@link ReceiveBufferSizePredictor} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link AdaptiveReceiveBufferSizePredictorFactory}(64, 1024, 65536)</tt>.
+     */
+    void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory);
+
     /**
      * @deprecated This property has been replaced by the
      * {@code writeBufferHighWaterMark} and {@code writeBufferLowWaterMark}.

src/main/java/org/jboss/netty/channel/xnio/DefaultXnioChannelConfig.java

@@ -20,9 +20,11 @@ import java.util.Map.Entry;
 
 import org.jboss.netty.buffer.ChannelBufferFactory;
 import org.jboss.netty.buffer.HeapChannelBufferFactory;
-import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictor;
+import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictorFactory;
+import org.jboss.netty.channel.ChannelException;
 import org.jboss.netty.channel.ChannelPipelineFactory;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 import org.jboss.netty.logging.InternalLogger;
 import org.jboss.netty.logging.InternalLoggerFactory;
 import org.jboss.netty.util.internal.ConversionUtil;
@@ -41,12 +43,15 @@ final class DefaultXnioChannelConfig implements XnioChannelConfig {
     private static final InternalLogger logger =
         InternalLoggerFactory.getInstance(DefaultXnioChannelConfig.class);
 
+    private static final ReceiveBufferSizePredictorFactory DEFAULT_PREDICTOR_FACTORY =
+        new AdaptiveReceiveBufferSizePredictorFactory();
+
     private volatile ChannelBufferFactory bufferFactory = HeapChannelBufferFactory.getInstance();
     private volatile ChannelPipelineFactory pipelineFactory;
     private volatile int writeBufferHighWaterMark = 64 * 1024;
     private volatile int writeBufferLowWaterMark  = 32 * 1024;
-    private volatile ReceiveBufferSizePredictor predictor =
-        new AdaptiveReceiveBufferSizePredictor();
+    private volatile ReceiveBufferSizePredictor predictor;
+    private volatile ReceiveBufferSizePredictorFactory predictorFactory = DEFAULT_PREDICTOR_FACTORY;
     private volatile int writeSpinCount = 16;
 
     DefaultXnioChannelConfig() {
@@ -145,6 +150,17 @@ final class DefaultXnioChannelConfig implements XnioChannelConfig {
     }
 
     public ReceiveBufferSizePredictor getReceiveBufferSizePredictor() {
+        ReceiveBufferSizePredictor predictor = this.predictor;
+        if (predictor == null) {
+            try {
+                this.predictor = predictor = getReceiveBufferSizePredictorFactory().getPredictor();
+            } catch (Exception e) {
+                throw new ChannelException(
+                        "Failed to create a new " +
+                        ReceiveBufferSizePredictor.class.getSimpleName() + '.',
+                        e);
+            }
+        }
         return predictor;
     }
 
@@ -156,6 +172,17 @@ final class DefaultXnioChannelConfig implements XnioChannelConfig {
         this.predictor = predictor;
     }
 
+    public ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory() {
+        return predictorFactory;
+    }
+
+    public void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory) {
+        if (predictorFactory == null) {
+            throw new NullPointerException("predictorFactory");
+        }
+        this.predictorFactory = predictorFactory;
+    }
+
     public ChannelPipelineFactory getPipelineFactory() {
         return pipelineFactory;
     }

src/main/java/org/jboss/netty/channel/xnio/XnioChannelConfig.java

@@ -19,8 +19,10 @@ import java.nio.ByteBuffer;
 import java.nio.channels.WritableByteChannel;
 
 import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictor;
+import org.jboss.netty.channel.AdaptiveReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.ChannelConfig;
 import org.jboss.netty.channel.ReceiveBufferSizePredictor;
+import org.jboss.netty.channel.ReceiveBufferSizePredictorFactory;
 import org.jboss.netty.channel.socket.SocketChannelConfig;
 
 /**
@@ -39,6 +41,8 @@ import org.jboss.netty.channel.socket.SocketChannelConfig;
  * <td>{@code "writeSpinCount"}</td><td>{@link #setWriteSpinCount(int)}</td>
  * </tr><tr>
  * <td>{@code "receiveBufferSizePredictor"}</td><td>{@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}</td>
+ * </tr><tr>
+ * <td>{@code "receiveBufferSizePredictorFactory"}</td><td>{@link #setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory)}</td>
  * </tr>
  * </table>
  *
@@ -79,14 +83,34 @@ public interface XnioChannelConfig extends ChannelConfig {
     /**
      * Returns the {@link ReceiveBufferSizePredictor} which predicts the
      * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
+     * predictor is <tt>{@link AdaptiveReceiveBufferSizePredictor}(64, 1024, 65536)</tt>.
      */
     ReceiveBufferSizePredictor getReceiveBufferSizePredictor();
 
     /**
      * Sets the {@link ReceiveBufferSizePredictor} which predicts the
      * number of readable bytes in the socket receive buffer.  The default
-     * predictor is {@link AdaptiveReceiveBufferSizePredictor}.
+     * predictor is <tt>{@link AdaptiveReceiveBufferSizePredictor}(64, 1024, 65536)</tt>.
      */
     void setReceiveBufferSizePredictor(ReceiveBufferSizePredictor predictor);
+
+    /**
+     * Returns the {@link ReceiveBufferSizePredictorFactory} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link AdaptiveReceiveBufferSizePredictorFactory}(64, 1024, 65536)</tt>.
+     */
+    ReceiveBufferSizePredictorFactory getReceiveBufferSizePredictorFactory();
+
+    /**
+     * Sets the {@link ReceiveBufferSizePredictor} which creates a new
+     * {@link ReceiveBufferSizePredictor} when a new channel is created and
+     * no {@link ReceiveBufferSizePredictor} was set.  If no predictor was set
+     * for the channel, {@link #setReceiveBufferSizePredictor(ReceiveBufferSizePredictor)}
+     * will be called with the new predictor.  The default factory is
+     * <tt>{@link AdaptiveReceiveBufferSizePredictorFactory}(64, 1024, 65536)</tt>.
+     */
+    void setReceiveBufferSizePredictorFactory(ReceiveBufferSizePredictorFactory predictorFactory);
 }