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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: 1.20 $ $Date: 2004/11/07 02:17:56 $
30 */
31 public class MathException extends Exception {
32
33 /*** Serializable version identifier */
34 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
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 }