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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 org.jboss.netty.channel.socket.nio;
17  
18  import java.io.IOException;
19  import java.nio.channels.CancelledKeyException;
20  import java.nio.channels.Selector;
21  
22  import org.jboss.netty.logging.InternalLogger;
23  import org.jboss.netty.logging.InternalLoggerFactory;
24  
25  final class SelectorUtil {
26      private static final InternalLogger logger =
27          InternalLoggerFactory.getInstance(SelectorUtil.class);
28  
29      static final int DEFAULT_IO_THREADS = Runtime.getRuntime().availableProcessors() * 2;
30  
31      // Workaround for JDK NIO bug.
32      //
33      // See:
34      // - http://bugs.sun.com/view_bug.do?bug_id=6427854
35      // - https://github.com/netty/netty/issues/203
36      static {
37          String key = "sun.nio.ch.bugLevel";
38          try {
39              String buglevel = System.getProperty(key);
40              if (buglevel == null) {
41                  System.setProperty(key, "");
42              }
43          } catch (SecurityException e) {
44              if (logger.isDebugEnabled()) {
45                  logger.debug("Unable to get/set System Property '" + key + "'", e);
46              }
47          }
48      }
49  
50      static void select(Selector selector) throws IOException {
51          try {
52              selector.select(10);
53          } catch (CancelledKeyException e) {
54              if (logger.isDebugEnabled()) {
55                  logger.debug(
56                          CancelledKeyException.class.getSimpleName() +
57                          " raised by a Selector - JDK bug?", e);
58              }
59              // Harmless exception - log anyway
60          }
61      }
62  
63      private SelectorUtil() {
64          // Unused
65      }
66  }