View Javadoc

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 }