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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/JaxenException.java,v 1.12 2005/06/21 12:21:20 elharo Exp $
3    * $Revision: 1.12 $
4    * $Date: 2005/06/21 12:21:20 $
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: JaxenException.java,v 1.12 2005/06/21 12:21:20 elharo Exp $
60   */
61  
62  
63  package org.jaxen;
64  
65  import java.io.PrintStream;
66  import java.io.PrintWriter;
67  
68  
69  /***
70   * Generic Jaxen exception.
71   *
72   * <p> This is the root of all Jaxen exceptions. It may wrap other exceptions.
73   *
74   * @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
75   */
76  public class JaxenException extends org.jaxen.saxpath.SAXPathException
77  {
78      
79      static double javaVersion = 1.4;
80      
81      static {
82          try {
83              String versionString = System.getProperty("java.version");
84              versionString = versionString.substring(0, 3);
85              javaVersion = Double.valueOf(versionString).doubleValue();
86          }
87          catch (Exception ex) {
88              // The version string format changed so presumably it's
89              // 1.4 or later.
90          }
91      }
92      
93      /***
94       * Create an exception with a detail message.
95       *
96       * @param message the error message
97       */
98      public JaxenException( String message )
99      {
100         super( message );
101     }
102 
103     /***
104      * Create an exception caused by another exception.
105      *
106      * @param rootCause the root cause of this exception
107      */
108     public JaxenException( Throwable rootCause )
109     {
110         super( rootCause );
111     }
112     
113     /***
114      * Create a new JaxenException with the specified detail message
115      * and root cause.
116      * 
117      * @param message the detail message
118      * @param nestedException the cause of this exception
119      */
120     public JaxenException(String message, Throwable nestedException) {
121         super( message, nestedException );
122     }
123     
124     private Throwable cause;
125     private boolean causeSet = false;
126 
127     /***
128      * Returns the exception that caused this exception.
129      * This is necessary to implement Java 1.4 chained exception 
130      * functionality in a Java 1.3-compatible way.
131      * 
132      * @return the exception that caused this exception
133      */
134     public Throwable getCause() {
135         return cause;
136     }
137     
138 
139     /***
140      * Sets the exception that caused this exception.
141      * This is necessary to implement Java 1.4 chained exception 
142      * functionality in a Java 1.3-compatible way.
143      * 
144      * @param cause the exception wrapped in this runtime exception
145      * 
146      * @return this exception
147      */
148     public Throwable initCause(Throwable cause) {
149         if (causeSet) throw new IllegalStateException("Cause cannot be reset");
150         if (cause == this) throw new IllegalArgumentException("Exception cannot be its own cause");
151         causeSet = true;
152         this.cause = cause;
153         return this;
154     }
155 
156     public void printStackTrace( PrintStream s ) {
157         super.printStackTrace( s );
158         if ( javaVersion < 1.4 && getCause() != null ) 
159         {
160             s.print( "Caused by: " );
161             getCause().printStackTrace( s );
162         }
163     }
164     
165     public void printStackTrace( PrintWriter w ) {
166         super.printStackTrace( w );
167         // Avoid double printing the cause in 1.4 and later
168         if ( javaVersion < 1.4 && getCause() != null ) 
169         {
170             w.print( "Caused by: " );
171             getCause().printStackTrace( w );
172         }
173     }
174     
175 }
176