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    1   /*
    2    * Copyright 2009 Red Hat, Inc.
    3    *
    4    * Red Hat licenses this file to you under the Apache License, version 2.0
    5    * (the "License"); you may not use this file except in compliance with the
    6    * License.  You may obtain a copy of the License at:
    7    *
    8    *    http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.channel.socket.nio;
    17
    18  import java.nio.ByteBuffer;
    19  import java.nio.channels.WritableByteChannel;
    20
    21  import org.jboss.netty.channel.Channel;
    22  import org.jboss.netty.channel.ChannelConfig;
    23  import org.jboss.netty.channel.socket.DatagramChannel;
    24  import org.jboss.netty.channel.socket.DatagramChannelConfig;
    25
    26  /**
    27   * A {@link DatagramChannelConfig} for a NIO TCP/IP {@link DatagramChannel}.
    28   *
    29   * <h3>Available options</h3>
    30   *
    31   * In addition to the options provided by {@link ChannelConfig} and
    32   * {@link DatagramChannelConfig}, {@link NioDatagramChannelConfig} allows the
    33   * following options in the option map:
    34   *
    35   * <table border="1" cellspacing="0" cellpadding="6">
    36   * <tr>
    37   * <th>Name</th><th>Associated setter method</th>
    38   * </tr><tr>
    39   * <td>{@code "writeBufferHighWaterMark"}</td><td>{@link #setWriteBufferHighWaterMark(int)}</td>
    40   * </tr><tr>
    41   * <td>{@code "writeBufferLowWaterMark"}</td><td>{@link #setWriteBufferLowWaterMark(int)}</td>
    42   * </tr><tr>
    43   * <td>{@code "writeSpinCount"}</td><td>{@link #setWriteSpinCount(int)}</td>
    44   * </tr><tr>
    45   * </table>
    46   *
    47   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
    48   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
    49   * @author Daniel Bevenius (dbevenius@jboss.com)
    50   *
    51   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
    52   */
    53  public interface NioDatagramChannelConfig extends DatagramChannelConfig {
    54
    55      /**
    56       * Returns the high water mark of the write buffer.  If the number of bytes
    57       * queued in the write buffer exceeds this value, {@link Channel#isWritable()}
    58       * will start to return {@code true}.
    59       */
    60      int getWriteBufferHighWaterMark();
    61
    62      /**
    63       * Sets the high water mark of the write buffer.  If the number of bytes
    64       * queued in the write buffer exceeds this value, {@link Channel#isWritable()}
    65       * will start to return {@code true}.
    66       */
    67      void setWriteBufferHighWaterMark(int writeBufferHighWaterMark);
    68
    69      /**
    70       * Returns the low water mark of the write buffer.  Once the number of bytes
    71       * queued in the write buffer exceeded the
    72       * {@linkplain #setWriteBufferHighWaterMark(int) high water mark} and then
    73       * dropped down below this value, {@link Channel#isWritable()} will return
    74       * {@code false} again.
    75       */
    76      int getWriteBufferLowWaterMark();
    77
    78      /**
    79       * Sets the low water mark of the write buffer.  Once the number of bytes
    80       * queued in the write buffer exceeded the
    81       * {@linkplain #setWriteBufferHighWaterMark(int) high water mark} and then
    82       * dropped down below this value, {@link Channel#isWritable()} will return
    83       * {@code false} again.
    84       */
    85      void setWriteBufferLowWaterMark(int writeBufferLowWaterMark);
    86
    87      /**
    88       * Returns the maximum loop count for a write operation until
    89       * {@link WritableByteChannel#write(ByteBuffer)} returns a non-zero value.
    90       * It is similar to what a spin lock is used for in concurrency programming.
    91       * It improves memory utilization and write throughput depending on
    92       * the platform that JVM runs on.  The default value is {@code 16}.
    93       */
    94      int getWriteSpinCount();
    95
    96      /**
    97       * Sets the maximum loop count for a write operation until
    98       * {@link WritableByteChannel#write(ByteBuffer)} returns a non-zero value.
    99       * It is similar to what a spin lock is used for in concurrency programming.
    100      * It improves memory utilization and write throughput depending on
    101      * the platform that JVM runs on.  The default value is {@code 16}.
    102      *
    103      * @throws IllegalArgumentException
    104      *         if the specified value is {@code 0} or less than {@code 0}
    105      */
    106     void setWriteSpinCount(int writeSpinCount);
    107 }