1 /* 2 * Copyright 2003-2004 The Apache Software Foundation. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package org.apache.commons.math; 17 18 import java.io.PrintStream; 19 import java.io.PrintWriter; 20 21 22 /** 23 * Base class for commons-math checked exceptions. 24 * <p> 25 * Supports nesting, emulating JDK 1.4 behavior if necessary. 26 * <p> 27 * Adapted from {@link org.apache.commons.collections.FunctorException}. 28 * 29 * @version $Revision: 348519 $ $Date: 2005-11-23 12:12:18 -0700 (Wed, 23 Nov 2005) $ 30 */ 31 public class MathException extends Exception { 32 33 /** Serializable version identifier */ 34 private static final long serialVersionUID = -8594613561393443827L; 35 36 /** 37 * Does JDK support nested exceptions? 38 */ 39 private static final boolean JDK_SUPPORTS_NESTED; 40 41 static { 42 boolean flag = false; 43 try { 44 Throwable.class.getDeclaredMethod("getCause", new Class[0]); 45 flag = true; 46 } catch (NoSuchMethodException ex) { 47 flag = false; 48 } 49 JDK_SUPPORTS_NESTED = flag; 50 } 51 52 /** 53 * Root cause of the exception 54 */ 55 private final Throwable rootCause; 56 57 /** 58 * Constructs a new <code>MathException</code> with no 59 * detail message. 60 */ 61 public MathException() { 62 super(); 63 this.rootCause = null; 64 } 65 66 /** 67 * Constructs a new <code>MathException</code> with specified 68 * detail message. 69 * 70 * @param msg the error message. 71 */ 72 public MathException(String msg) { 73 super(msg); 74 this.rootCause = null; 75 } 76 77 /** 78 * Constructs a new <code>MathException</code> with specified 79 * nested <code>Throwable</code> root cause. 80 * 81 * @param rootCause the exception or error that caused this exception 82 * to be thrown. 83 */ 84 public MathException(Throwable rootCause) { 85 super((rootCause == null ? null : rootCause.getMessage())); 86 this.rootCause = rootCause; 87 } 88 89 /** 90 * Constructs a new <code>MathException</code> with specified 91 * detail message and nested <code>Throwable</code> root cause. 92 * 93 * @param msg the error message. 94 * @param rootCause the exception or error that caused this exception 95 * to be thrown. 96 */ 97 public MathException(String msg, Throwable rootCause) { 98 super(msg); 99 this.rootCause = rootCause; 100 } 101 102 /** 103 * Gets the cause of this throwable. 104 * 105 * @return the cause of this throwable, or <code>null</code> 106 */ 107 public Throwable getCause() { 108 return rootCause; 109 } 110 111 /** 112 * Prints the stack trace of this exception to the standard error stream. 113 */ 114 public void printStackTrace() { 115 printStackTrace(System.err); 116 } 117 118 /** 119 * Prints the stack trace of this exception to the specified stream. 120 * 121 * @param out the <code>PrintStream</code> to use for output 122 */ 123 public void printStackTrace(PrintStream out) { 124 synchronized (out) { 125 PrintWriter pw = new PrintWriter(out, false); 126 printStackTrace(pw); 127 // Flush the PrintWriter before it's GC'ed. 128 pw.flush(); 129 } 130 } 131 132 /** 133 * Prints the stack trace of this exception to the specified writer. 134 * 135 * @param out the <code>PrintWriter</code> to use for output 136 */ 137 public void printStackTrace(PrintWriter out) { 138 synchronized (out) { 139 super.printStackTrace(out); 140 if (rootCause != null && JDK_SUPPORTS_NESTED == false) { 141 out.print("Caused by: "); 142 rootCause.printStackTrace(out); 143 } 144 } 145 } 146 147 }