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.util.internal;
17
18 import java.util.ArrayList;
19 import java.util.List;
20 import java.util.regex.Pattern;
21
22 import org.jboss.netty.channel.DefaultChannelPipeline;
23 import org.jboss.netty.channel.SimpleChannelHandler;
24 import org.jboss.netty.channel.StaticChannelPipeline;
25 import org.jboss.netty.util.DebugUtil;
26 import org.jboss.netty.util.ThreadRenamingRunnable;
27
28 /**
29 * Simplifies an exception stack trace by removing unnecessary
30 * {@link StackTraceElement}s. Please note that the stack trace simplification
31 * is disabled if {@linkplain DebugUtil debug mode} is turned on.
32 *
33 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
34 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
35 *
36 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
37 *
38 */
39 public class StackTraceSimplifier {
40
41 private static final boolean SIMPLIFY_STACK_TRACE = !DebugUtil.isDebugEnabled();
42 private static final Pattern EXCLUDED_STACK_TRACE =
43 Pattern.compile(
44 "^org\\.jboss\\.netty\\." +
45 "(util\\.(ThreadRenamingRunnable|internal\\.DeadLockProofWorker)" +
46 "|channel\\.(SimpleChannel(Upstream|Downstream)?Handler|(Default|Static)ChannelPipeline.*))(\\$.*)?$");
47
48 /**
49 * Removes unnecessary {@link StackTraceElement}s from the specified
50 * exception. {@link ThreadRenamingRunnable}, {@link SimpleChannelHandler},
51 * {@link DefaultChannelPipeline}, and {@link StaticChannelPipeline}
52 * will be dropped from the trace.
53 */
54 public static void simplify(Throwable e) {
55 if (!SIMPLIFY_STACK_TRACE) {
56 return;
57 }
58
59 if (e.getCause() != null) {
60 simplify(e.getCause());
61 }
62
63 StackTraceElement[] trace = e.getStackTrace();
64 if (trace == null || trace.length == 0) {
65 return;
66 }
67
68 // Perhaps Netty bug. Let us not strip things out.
69 if (EXCLUDED_STACK_TRACE.matcher(trace[0].getClassName()).matches()) {
70 return;
71 }
72
73 List<StackTraceElement> simpleTrace =
74 new ArrayList<StackTraceElement>(trace.length);
75
76 simpleTrace.add(trace[0]);
77
78 // Remove unnecessary stack trace elements.
79 for (int i = 1; i < trace.length; i ++) {
80 if (EXCLUDED_STACK_TRACE.matcher(trace[i].getClassName()).matches()) {
81 continue;
82 }
83 simpleTrace.add(trace[i]);
84 }
85
86 e.setStackTrace(
87 simpleTrace.toArray(new StackTraceElement[simpleTrace.size()]));
88 }
89 }