/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/* ident        "%Z%%M% %I%     %E% SMI" */

package com.sun.solaris.service.exception;

import java.io.*;

/**
 * Formats a stack trace in a single line.  The format is meant to
 * convey the stack trace as a sequence of class names and line numbers,
 * with the topmost frame first, suitable for logging.  Beware, the
 * format may evolve.
 */
public class SuccinctStackTraceFormatter {
        /**
         * Formats a Throwable and adds an optional description string.
         * The string should be suitable to precede the top stack
         * element, and include any punctuation that should
         * differentiate it from the element.
         */
        public static String formatWithDescription(Throwable t,
            String description)
        {
                StringBuffer s = new StringBuffer();

                s.append("(");

                if (description != null)
                        s.append(description);

                s.append(t.getClass().getName());
                s.append(", ");
                StackTraceElement[] trace = t.getStackTrace();
                for (int i = 0; i < trace.length; i++) {
                        appendStackTraceElement(i > 0 ? trace[i - 1] : null,
                            trace[i], s);
                        if (i != trace.length - 1)
                                s.append(", ");
                }
                s.append(")");

                if (t.getCause() != null) {
                        s.append(" caused by ");
                        s.append(format(t.getCause()));
                }

                return (s.toString());
        }

        /**
         * Formats a Throwable's stack trace.  The format is meant to be
         * a single line of output, conveying the stack trace as a
         * sequence of class names and line numbers, with the topmost
         * frame first, suitable for logging.  If two adjacent stack
         * trace elements share some portion of a class name, the
         * bottommost element may have the common part replaced with an
         * ampersand.
         */
        public static String format(Throwable t)
        {
                return (formatWithDescription(t, null));
        }

        /**
         * Formats a stack trace element as per <code>format()</code>.
         */
        private static void appendStackTraceElement(StackTraceElement last,
            StackTraceElement e, StringBuffer s)
        {
                /*
                 * This could grab more of a common class name.  (See
                 * SuccinctStackTraceFormatter.format())
                 */
                if (last == null || !last.getClassName().equals(
                    e.getClassName())) {
                        s.append(e.getClassName());
                        s.append(".");
                } else
                        s.append("&.");

                s.append(e.getMethodName());
                if (e.getLineNumber() > 0) {
                        s.append(":");
                        s.append(e.getLineNumber());
                }
                if (e.isNativeMethod()) {
                        s.append(":");
                        s.append("native");
                }
        }

        public static void printStackTrace(Throwable t)
        {
                printStackTrace(t, System.err);
        }

        public static void printStackTrace(Throwable t, PrintStream out)
        {
                out.print(t);
                out.print(" at ");
                out.print(format(t));
        }

        public static final void main(String args[])
        {
                SuccinctStackTraceFormatter.printStackTrace(big());
        }

        public static final Throwable big() {
                return new Throwable().initCause(little());
        }

        public static final Throwable little() {
                return new Throwable();
        }

}