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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the 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 io.netty.channel.nio;
17  
18  import io.netty.channel.Channel;
19  import io.netty.channel.DefaultSelectStrategyFactory;
20  import io.netty.channel.MultithreadEventLoopGroup;
21  import io.netty.channel.SelectStrategyFactory;
22  import io.netty.util.concurrent.EventExecutor;
23  import io.netty.util.concurrent.RejectedExecutionHandler;
24  import io.netty.util.concurrent.RejectedExecutionHandlers;
25  
26  import java.nio.channels.Selector;
27  import java.nio.channels.spi.SelectorProvider;
28  import java.util.concurrent.ThreadFactory;
29  
30  /**
31   * {@link MultithreadEventLoopGroup} implementations which is used for NIO {@link Selector} based {@link Channel}s.
32   */
33  public class NioEventLoopGroup extends MultithreadEventLoopGroup {
34  
35      /**
36       * Create a new instance using the default number of threads, the default {@link ThreadFactory} and
37       * the {@link SelectorProvider} which is returned by {@link SelectorProvider#provider()}.
38       */
39      public NioEventLoopGroup() {
40          this(0);
41      }
42  
43      /**
44       * Create a new instance using the specified number of threads, {@link ThreadFactory} and the
45       * {@link SelectorProvider} which is returned by {@link SelectorProvider#provider()}.
46       */
47      public NioEventLoopGroup(int nThreads) {
48          this(nThreads, null);
49      }
50  
51      /**
52       * Create a new instance using the specified number of threads, the given {@link ThreadFactory} and the
53       * {@link SelectorProvider} which is returned by {@link SelectorProvider#provider()}.
54       */
55      public NioEventLoopGroup(int nThreads, ThreadFactory threadFactory) {
56          this(nThreads, threadFactory, SelectorProvider.provider());
57      }
58  
59      /**
60       * Create a new instance using the specified number of threads, the given {@link ThreadFactory} and the given
61       * {@link SelectorProvider}.
62       */
63      public NioEventLoopGroup(
64              int nThreads, ThreadFactory threadFactory, final SelectorProvider selectorProvider) {
65          this(nThreads, threadFactory, selectorProvider, DefaultSelectStrategyFactory.INSTANCE);
66      }
67  
68      public NioEventLoopGroup(int nThreads, ThreadFactory threadFactory,
69          final SelectorProvider selectorProvider, final SelectStrategyFactory selectStrategyFactory) {
70          super(nThreads, threadFactory, selectorProvider, selectStrategyFactory, RejectedExecutionHandlers.reject());
71      }
72  
73      public NioEventLoopGroup(int nThreads, ThreadFactory threadFactory,
74                               final SelectorProvider selectorProvider,
75                               final SelectStrategyFactory selectStrategyFactory,
76                               final RejectedExecutionHandler rejectedExecutionHandler) {
77          super(nThreads, threadFactory, selectorProvider, selectStrategyFactory, rejectedExecutionHandler);
78      }
79  
80      /**
81       * Sets the percentage of the desired amount of time spent for I/O in the child event loops.  The default value is
82       * {@code 50}, which means the event loop will try to spend the same amount of time for I/O as for non-I/O tasks.
83       */
84      public void setIoRatio(int ioRatio) {
85          for (EventExecutor e: children()) {
86              ((NioEventLoop) e).setIoRatio(ioRatio);
87          }
88      }
89  
90      /**
91       * Replaces the current {@link Selector}s of the child event loops with newly created {@link Selector}s to work
92       * around the  infamous epoll 100% CPU bug.
93       */
94      public void rebuildSelectors() {
95          for (EventExecutor e: children()) {
96              ((NioEventLoop) e).rebuildSelector();
97          }
98      }
99  
100     @Override
101     protected EventExecutor newChild(ThreadFactory threadFactory, Object... args) throws Exception {
102         return new NioEventLoop(this, threadFactory, (SelectorProvider) args[0],
103             ((SelectStrategyFactory) args[1]).newSelectStrategy(), (RejectedExecutionHandler) args[2]);
104     }
105 }