xref: /illumos-gate/usr/src/cmd/pools/poold/com/sun/solaris/service/exception/SuccinctStackTraceFormatter.java (revision 55fea89dcaa64928bed4327112404dcb3e07b79f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /* ident	"%Z%%M%	%I%	%E% SMI" */
28 
29 package com.sun.solaris.service.exception;
30 
31 import java.io.*;
32 
33 /**
34  * Formats a stack trace in a single line.  The format is meant to
35  * convey the stack trace as a sequence of class names and line numbers,
36  * with the topmost frame first, suitable for logging.  Beware, the
37  * format may evolve.
38  */
39 public class SuccinctStackTraceFormatter {
40 	/**
41 	 * Formats a Throwable and adds an optional description string.
42 	 * The string should be suitable to precede the top stack
43 	 * element, and include any punctuation that should
44 	 * differentiate it from the element.
45 	 */
formatWithDescription(Throwable t, String description)46 	public static String formatWithDescription(Throwable t,
47 	    String description)
48 	{
49 		StringBuffer s = new StringBuffer();
50 
51 		s.append("(");
52 
53 		if (description != null)
54 			s.append(description);
55 
56 		s.append(t.getClass().getName());
57 		s.append(", ");
58 		StackTraceElement[] trace = t.getStackTrace();
59 		for (int i = 0; i < trace.length; i++) {
60 			appendStackTraceElement(i > 0 ? trace[i - 1] : null,
61 			    trace[i], s);
62 			if (i != trace.length - 1)
63 				s.append(", ");
64 		}
65 		s.append(")");
66 
67 		if (t.getCause() != null) {
68 			s.append(" caused by ");
69 			s.append(format(t.getCause()));
70 		}
71 
72 		return (s.toString());
73 	}
74 
75 	/**
76 	 * Formats a Throwable's stack trace.  The format is meant to be
77 	 * a single line of output, conveying the stack trace as a
78 	 * sequence of class names and line numbers, with the topmost
79 	 * frame first, suitable for logging.  If two adjacent stack
80 	 * trace elements share some portion of a class name, the
81 	 * bottommost element may have the common part replaced with an
82 	 * ampersand.
83 	 */
format(Throwable t)84 	public static String format(Throwable t)
85 	{
86 		return (formatWithDescription(t, null));
87 	}
88 
89 	/**
90 	 * Formats a stack trace element as per <code>format()</code>.
91 	 */
appendStackTraceElement(StackTraceElement last, StackTraceElement e, StringBuffer s)92 	private static void appendStackTraceElement(StackTraceElement last,
93 	    StackTraceElement e, StringBuffer s)
94 	{
95 		/*
96 		 * This could grab more of a common class name.  (See
97 		 * SuccinctStackTraceFormatter.format())
98 		 */
99 		if (last == null || !last.getClassName().equals(
100 		    e.getClassName())) {
101 			s.append(e.getClassName());
102 			s.append(".");
103 		} else
104 			s.append("&.");
105 
106 		s.append(e.getMethodName());
107 		if (e.getLineNumber() > 0) {
108 			s.append(":");
109 			s.append(e.getLineNumber());
110 		}
111 		if (e.isNativeMethod()) {
112 			s.append(":");
113 			s.append("native");
114 		}
115 	}
116 
printStackTrace(Throwable t)117 	public static void printStackTrace(Throwable t)
118 	{
119 		printStackTrace(t, System.err);
120 	}
121 
printStackTrace(Throwable t, PrintStream out)122 	public static void printStackTrace(Throwable t, PrintStream out)
123 	{
124 		out.print(t);
125 		out.print(" at ");
126 		out.print(format(t));
127 	}
128 
main(String args[])129 	public static final void main(String args[])
130 	{
131 		SuccinctStackTraceFormatter.printStackTrace(big());
132 	}
133 
big()134 	public static final Throwable big() {
135 		return new Throwable().initCause(little());
136 	}
137 
little()138 	public static final Throwable little() {
139 		return new Throwable();
140 	}
141 
142 }
143