Java tutorial
package com.free.exception; /* ==================================================================== * The Apache Software License, Version 1.1 * * Copyright (c) 2002-2003 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. 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Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. */ import java.io.PrintStream; import java.io.PrintWriter; /** * The base class of all exceptions which can contain other exceptions. * <p/> * It is intended to ease the debugging by carrying on the information about the * exception which was caught and provoked throwing the current exception. * Catching and rethrowing may occur multiple times, and provided that all * exceptions except the first one are descendands of * <code>NestedException</code>, when the exception is finally printed out using * any of the <code> * printStackTrace()</code> methods, the stacktrace will contain the information * about all exceptions thrown and caught on the way. * <p> * Running the following program * <p> * <blockquote> * * <pre> * 1 import org.apache.commons.lang.exception.NestableException; * 2 * 3 public class Test { * 4 public static void main( String[] args ) { * 5 try { * 6 a(); * 7 } catch(Exception e) { * 8 e.printStackTrace(); * 9 } * 10 } * 11 * 12 public static void a() throws Exception { * 13 try { * 14 b(); * 15 } catch(Exception e) { * 16 throw new NestableException("foo", e); * 17 } * 18 } * 19 * 20 public static void b() throws Exception { * 21 try { * 22 c(); * 23 } catch(Exception e) { * 24 throw new NestableException("bar", e); * 25 } * 26 } * 27 * 28 public static void c() throws Exception { * 29 throw new Exception("baz"); * 30 } * 31 } * </pre> * * </blockquote> * <p> * Yields the following stacktrace: * <p> * <blockquote> * * <pre> * org.apache.commons.lang.exception.NestableException: foo * at Test.a(Test.java:16) * at Test.main(Test.java:6) * Caused by: org.apache.commons.lang.exception.NestableException: bar * at Test.b(Test.java:24) * at Test.a(Test.java:14) * ... 1 more * Caused by: java.lang.Exception: baz * at Test.c(Test.java:29) * at Test.b(Test.java:22) * ... 2 more * </pre> * * </blockquote><br> * * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a> * @author <a href="mailto:dlr@collab.net">Daniel Rall</a> * @author <a href="mailto:knielsen@apache.org">Kasper Nielsen</a> * @author <a href="mailto:steven@caswell.name">Steven Caswell</a> * @version $Id: NestableException.java,v 1.2 2004/11/21 00:11:27 pgmjsd Exp $ * @since 1.0 */ public class NestableException extends Exception implements Nestable { private static final long serialVersionUID = -1660820507904294457L; /** * The helper instance which contains much of the code which we delegate to. */ protected NestableDelegate delegate = new NestableDelegate(this); /** * Holds the reference to the exception or error that caused this exception to * be thrown. */ private Throwable cause = null; /** * Constructs a new <code>NestableException</code> without specified detail * message. */ public NestableException() { super(); } /** * Constructs a new <code>NestableException</code> with specified detail * message. * * @param msg * The error message. */ public NestableException(String msg) { super(msg); } /** * Constructs a new <code>NestableException</code> with specified nested * <code>Throwable</code>. * * @param cause * the exception or error that caused this exception to be thrown */ public NestableException(Throwable cause) { super(); this.cause = cause; } /** * Constructs a new <code>NestableException</code> with specified detail * message and nested <code>Throwable</code>. * * @param msg * the error message * @param cause * the exception or error that caused this exception to be thrown */ public NestableException(String msg, Throwable cause) { super(msg); this.cause = cause; } public Throwable getCause() { return cause; } /** * Returns the detail message string of this throwable. If it was created with * a null message, returns the following: ( cause==null ? null : * cause.toString() ). */ public String getMessage() { if (super.getMessage() != null) { return super.getMessage(); } else if (cause != null) { return cause.toString(); } else { return null; } } public String getMessage(int index) { if (index == 0) { return super.getMessage(); } else { return delegate.getMessage(index); } } public String[] getMessages() { return delegate.getMessages(); } public Throwable getThrowable(int index) { return delegate.getThrowable(index); } public int getThrowableCount() { return delegate.getThrowableCount(); } public Throwable[] getThrowables() { return delegate.getThrowables(); } public int indexOfThrowable(Class<?> type) { return delegate.indexOfThrowable(type, 0); } public int indexOfThrowable(Class<?> type, int fromIndex) { return delegate.indexOfThrowable(type, fromIndex); } public void printStackTrace() { delegate.printStackTrace(); } public void printStackTrace(PrintStream out) { delegate.printStackTrace(out); } public void printStackTrace(PrintWriter out) { delegate.printStackTrace(out); } public final void printPartialStackTrace(PrintWriter out) { super.printStackTrace(out); } }