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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.util;
17  
18  import org.jboss.netty.channel.ChannelPipeline;
19  import org.jboss.netty.channel.ChannelSink;
20  import org.jboss.netty.util.internal.SystemPropertyUtil;
21  
22  /**
23   * Determines if Netty is running in a debug mode or not.  Please note that
24   * this is not a Java debug mode.  You can enable Netty debug mode by
25   * specifying the {@code "org.jboss.netty.debug"} system property (e.g.
26   * {@code java -Dorg.jboss.netty.debug ...})
27   * <p>
28   * If debug mode is disabled (default), the stack trace of the exceptions are
29   * compressed to help debugging a user application.
30   * <p>
31   * If debug mode is enabled, the stack trace of the exceptions raised in
32   * {@link ChannelPipeline} or {@link ChannelSink} are retained as it is to help
33   * debugging Netty.
34   */
35  public final class DebugUtil {
36  
37      /**
38       * Returns {@code true} if and only if Netty debug mode is enabled.
39       */
40      public static boolean isDebugEnabled() {
41          String value;
42          try {
43              value = SystemPropertyUtil.get("org.jboss.netty.debug");
44          } catch (Exception e) {
45              value = null;
46          }
47  
48          if (value == null) {
49              return false;
50          }
51  
52          value = value.trim().toUpperCase();
53          return !value.startsWith("N") &&
54                 !value.startsWith("F") &&
55                 !value.equals("0");
56      }
57  
58      private DebugUtil() {
59          // Unused
60      }
61  }