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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/saxpath/SAXPathException.java,v 1.10 2005/06/21 12:33:13 elharo Exp $
3    * $Revision: 1.10 $
4    * $Date: 2005/06/21 12:33:13 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions
13   * are met:
14   *
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows
20   *    these conditions in the documentation and/or other materials
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   *
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   *
31   * In addition, we request (but do not require) that you include in the
32   * end-user documentation provided with the redistribution and/or in the
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many
54   * individuals on behalf of the Jaxen Project and was originally
55   * created by bob mcwhirter <bob@werken.com> and
56   * James Strachan <jstrachan@apache.org>.  For more information on the
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   *
59   * $Id: SAXPathException.java,v 1.10 2005/06/21 12:33:13 elharo Exp $
60   */
61  
62  package org.jaxen.saxpath;
63  
64  import java.io.PrintStream;
65  import java.io.PrintWriter;
66  
67  /*** Base of all SAXPath exceptions.
68   *
69   *  @author bob mcwhirter (bob@werken.com)
70   */
71  public class SAXPathException extends Exception
72  {
73      
74      static double javaVersion = 1.4;
75      
76      static {
77          try {
78              String versionString = System.getProperty("java.version");
79              versionString = versionString.substring(0, 3);
80              javaVersion = Double.valueOf(versionString).doubleValue();
81          }
82          catch (Exception ex) {
83              // The version string format changed so presumably it's
84              // 1.4 or later.
85          }
86      }
87      
88      /*** Create a new SAXPathException with a given message.
89       *
90       *  @param message the error message
91       */
92      public SAXPathException(String message)
93      {
94          super( message );
95      }
96  
97      /*** Create a new SAXPathException based on another exception
98       *
99       *  @param cause the error source
100      */
101     public SAXPathException(Throwable cause)
102     {
103     	super ( cause.getMessage() );
104     	initCause(cause);
105     }
106 
107     /***
108      * Create a new SAXPathException with the specified detail message
109      * and root cause.
110      * 
111      * @param message the detail message
112      * @param cause the cause of this exception
113      */
114     public SAXPathException(String message, Throwable cause) {
115         super( message );
116         initCause(cause);
117     }
118     
119     
120     private Throwable cause;
121     private boolean causeSet = false;
122 
123     /***
124      * Returns the exception that caused this exception.
125      * This is necessary to implement Java 1.4 chained exception 
126      * functionality in a Java 1.3-compatible way.
127      * 
128      * @return the exception that caused this exception
129      */
130     public Throwable getCause() {
131         return cause;
132     }
133     
134 
135     /***
136      * Sets the exception that caused this exception.
137      * This is necessary to implement Java 1.4 chained exception 
138      * functionality in a Java 1.3-compatible way.
139      * 
140      * @param cause the exception wrapped in this runtime exception
141      * 
142      * @return this exception
143      */
144     public Throwable initCause(Throwable cause) {
145         if (causeSet) throw new IllegalStateException("Cause cannot be reset");
146         if (cause == this) throw new IllegalArgumentException("Exception cannot be its own cause");
147         causeSet = true;
148         this.cause = cause;
149         return this;
150     }
151 
152     /*** Print this exception's stack trace, followed by the
153      *	source exception's trace, if any.
154      *
155      * @param s the stream on which to print the stack trace
156      */
157     public void printStackTrace ( PrintStream s )
158     {
159     	super.printStackTrace ( s );
160     	if (javaVersion < 1.4 && getCause() != null) {
161     	    s.print( "Caused by: " );
162     	    getCause().printStackTrace( s );
163     	}
164     }
165 
166     /*** Print this exception's stack trace, followed by the
167      *	source exception's stack trace, if any.
168      *
169      * @param s the writer on which to print the stack trace
170      */
171     public void printStackTrace ( PrintWriter s )
172     {
173     	super.printStackTrace( s );
174     	if (javaVersion < 1.4 && getCause() != null) {
175     	    s.print( "Caused by: " );
176     	    getCause().printStackTrace( s );
177     	}
178     }
179 
180 }