NioChannelConfig.java

/*
 * Copyright 2012 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 org.jboss.netty.channel.socket.nio;

import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;

import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelConfig;

/**
 * Special {@link ChannelConfig} sub-type which offers extra methods which are useful for NIO.
 *
 */
public interface NioChannelConfig extends ChannelConfig {

    /**
     * Returns the high water mark of the write buffer.  If the number of bytes
     * queued in the write buffer exceeds this value, {@link Channel#isWritable()}
     * will start to return {@code false}.
     */
    int getWriteBufferHighWaterMark();

    /**
     * Sets the high water mark of the write buffer.  If the number of bytes
     * queued in the write buffer exceeds this value, {@link Channel#isWritable()}
     * will start to return {@code false}.
     */
    void setWriteBufferHighWaterMark(int writeBufferHighWaterMark);

    /**
     * Returns the low water mark of the write buffer.  Once the number of bytes
     * queued in the write buffer exceeded the
     * {@linkplain #setWriteBufferHighWaterMark(int) high water mark} and then
     * dropped down below this value, {@link Channel#isWritable()} will start to return
     * {@code true} again.
     */
    int getWriteBufferLowWaterMark();

    /**
     * Sets the low water mark of the write buffer.  Once the number of bytes
     * queued in the write buffer exceeded the
     * {@linkplain #setWriteBufferHighWaterMark(int) high water mark} and then
     * dropped down below this value, {@link Channel#isWritable()} will start toreturn
     * {@code true} again.
     */
    void setWriteBufferLowWaterMark(int writeBufferLowWaterMark);

    /**
     * Returns the maximum loop count for a write operation until
     * {@link WritableByteChannel#write(ByteBuffer)} returns a non-zero value.
     * It is similar to what a spin lock is used for in concurrency programming.
     * It improves memory utilization and write throughput depending on
     * the platform that JVM runs on.  The default value is {@code 16}.
     */
    int getWriteSpinCount();

    /**
     * Sets the maximum loop count for a write operation until
     * {@link WritableByteChannel#write(ByteBuffer)} returns a non-zero value.
     * It is similar to what a spin lock is used for in concurrency programming.
     * It improves memory utilization and write throughput depending on
     * the platform that JVM runs on.  The default value is {@code 16}.
     *
     * @throws IllegalArgumentException
     *         if the specified value is {@code 0} or less than {@code 0}
     */
    void setWriteSpinCount(int writeSpinCount);
}