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1: /* ======================================================================== 2: * JCommon : a free general purpose class library for the Java(tm) platform 3: * ======================================================================== 4: * 5: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jcommon/index.html 8: * 9: * This library is free software; you can redistribute it and/or modify it 10: * under the terms of the GNU Lesser General Public License as published by 11: * the Free Software Foundation; either version 2.1 of the License, or 12: * (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but 15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17: * License for more details. 18: * 19: * You should have received a copy of the GNU Lesser General Public 20: * License along with this library; if not, write to the Free Software 21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 22: * USA. 23: * 24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 25: * in the United States and other countries.] 26: * 27: * ----------------------- 28: * StackableException.java 29: * ----------------------- 30: * (C)opyright 2002-2004, by Thomas Morgner and Contributors. 31: * 32: * Original Author: Thomas Morgner; 33: * Contributor(s): David Gilbert (for Object Refinery Limited); 34: * 35: * $Id: StackableException.java,v 1.3 2005/11/14 10:56:55 mungady Exp $ 36: * 37: * Changes 38: * ------- 39: * 06-Dec-2002 : Initial version 40: * 10-Dec-2002 : Fixed issues reported by Checkstyle (DG); 41: * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon 42: * 43: */ 44: 45: package org.jfree.util; 46: 47: import java.io.PrintStream; 48: import java.io.PrintWriter; 49: 50: /** 51: * A baseclass for exceptions, which could have parent exceptions. These parent exceptions 52: * are raised in a subclass and are now wrapped into a subclass of this Exception. 53: * <p> 54: * The parents are printed when this exception is printed. This class exists mainly for 55: * debugging reasons, as with them it is easier to detect the root cause of an error. 56: * 57: * <!-- In a perfect world there would be no need for such a class :)--> 58: * 59: * @author Thomas Morgner 60: */ 61: public abstract class StackableException extends Exception { 62: 63: /** The parent exception. */ 64: private Exception parent; 65: 66: /** 67: * Creates a StackableRuntimeException with no message and no parent. 68: */ 69: public StackableException() { 70: super(); 71: } 72: 73: /** 74: * Creates an exception. 75: * 76: * @param message the exception message. 77: * @param ex the parent exception. 78: */ 79: public StackableException(final String message, final Exception ex) { 80: super(message); 81: this.parent = ex; 82: } 83: 84: /** 85: * Creates an exception. 86: * 87: * @param message the exception message. 88: */ 89: public StackableException(final String message) { 90: super(message); 91: } 92: 93: /** 94: * Returns the parent exception (possibly null). 95: * 96: * @return the parent exception. 97: */ 98: public Exception getParent() { 99: return this.parent; 100: } 101: 102: /** 103: * Prints the stack trace to the specified stream. 104: * 105: * @param stream the output stream. 106: */ 107: public void printStackTrace(final PrintStream stream) { 108: super.printStackTrace(stream); 109: if (getParent() != null) { 110: stream.println("ParentException: "); 111: getParent().printStackTrace(stream); 112: } 113: } 114: 115: /** 116: * Prints the stack trace to the specified writer. 117: * 118: * @param writer the writer. 119: */ 120: public void printStackTrace(final PrintWriter writer) { 121: super.printStackTrace(writer); 122: if (getParent() != null) { 123: writer.println("ParentException: "); 124: getParent().printStackTrace(writer); 125: } 126: } 127: 128: /** 129: * Prints this <code>Throwable</code> and its backtrace to the 130: * standard error stream. This method prints a stack trace for this 131: * <code>Throwable</code> object on the error output stream that is 132: * the value of the field <code>System.err</code>. The first line of 133: * output contains the result of the {@link #toString()} method for 134: * this object. Remaining lines represent data previously recorded by 135: * the method {@link #fillInStackTrace()}. The format of this 136: * information depends on the implementation, but the following 137: * example may be regarded as typical: 138: * <blockquote><pre> 139: * java.lang.NullPointerException 140: * at MyClass.mash(MyClass.java:9) 141: * at MyClass.crunch(MyClass.java:6) 142: * at MyClass.main(MyClass.java:3) 143: * </pre></blockquote> 144: * This example was produced by running the program: 145: * <blockquote><pre> 146: * 147: * class MyClass { 148: * 149: * public static void main(String[] argv) { 150: * crunch(null); 151: * } 152: * static void crunch(int[] a) { 153: * mash(a); 154: * } 155: * 156: * static void mash(int[] b) { 157: * System.out.println(b[0]); 158: * } 159: * } 160: * </pre></blockquote> 161: * 162: * @see System#err 163: */ 164: public void printStackTrace() { 165: synchronized (System.err) { 166: printStackTrace(System.err); 167: } 168: } 169: }