001: /* ========================================================================
002: * JCommon : a free general purpose class library for the Java(tm) platform
003: * ========================================================================
004: *
005: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006: *
007: * Project Info: http://www.jfree.org/jcommon/index.html
008: *
009: * This library is free software; you can redistribute it and/or modify it
010: * under the terms of the GNU Lesser General Public License as published by
011: * the Free Software Foundation; either version 2.1 of the License, or
012: * (at your option) any later version.
013: *
014: * This library is distributed in the hope that it will be useful, but
015: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017: * License for more details.
018: *
019: * You should have received a copy of the GNU Lesser General Public
020: * License along with this library; if not, write to the Free Software
021: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022: * USA.
023: *
024: * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025: * in the United States and other countries.]
026: *
027: * -----------------------
028: * StackableException.java
029: * -----------------------
030: * (C)opyright 2002-2004, by Thomas Morgner and Contributors.
031: *
032: * Original Author: Thomas Morgner;
033: * Contributor(s): David Gilbert (for Object Refinery Limited);
034: *
035: * $Id: StackableException.java,v 1.3 2005/11/14 10:56:55 mungady Exp $
036: *
037: * Changes
038: * -------
039: * 06-Dec-2002 : Initial version
040: * 10-Dec-2002 : Fixed issues reported by Checkstyle (DG);
041: * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon
042: *
043: */
044:
045: package org.jfree.util;
046:
047: import java.io.PrintStream;
048: import java.io.PrintWriter;
049:
050: /**
051: * A baseclass for exceptions, which could have parent exceptions. These parent exceptions
052: * are raised in a subclass and are now wrapped into a subclass of this Exception.
053: * <p>
054: * The parents are printed when this exception is printed. This class exists mainly for
055: * debugging reasons, as with them it is easier to detect the root cause of an error.
056: *
057: * <!-- In a perfect world there would be no need for such a class :)-->
058: *
059: * @author Thomas Morgner
060: */
061: public abstract class StackableException extends Exception {
062:
063: /** The parent exception. */
064: private Exception parent;
065:
066: /**
067: * Creates a StackableRuntimeException with no message and no parent.
068: */
069: public StackableException() {
070: super ();
071: }
072:
073: /**
074: * Creates an exception.
075: *
076: * @param message the exception message.
077: * @param ex the parent exception.
078: */
079: public StackableException(final String message, final Exception ex) {
080: super (message);
081: this .parent = ex;
082: }
083:
084: /**
085: * Creates an exception.
086: *
087: * @param message the exception message.
088: */
089: public StackableException(final String message) {
090: super (message);
091: }
092:
093: /**
094: * Returns the parent exception (possibly null).
095: *
096: * @return the parent exception.
097: */
098: public Exception getParent() {
099: 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: }
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