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1   /*
2    * $Header$
3    * $Revision$
4    * $Date$
5    *
6    * ====================================================================
7    *
8    * Copyright 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   *
12   * Redistribution and use in source and binary forms, with or without
13   * modification, are permitted provided that the following conditions are
14   * met:
15   * 
16   *   * Redistributions of source code must retain the above copyright
17   *     notice, this list of conditions and the following disclaimer.
18   * 
19   *   * Redistributions in binary form must reproduce the above copyright
20   *     notice, this list of conditions and the following disclaimer in the
21   *     documentation and/or other materials provided with the distribution.
22   * 
23   *   * Neither the name of the Jaxen Project nor the names of its
24   *     contributors may be used to endorse or promote products derived 
25   *     from this software without specific prior written permission.
26   * 
27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
28   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
30   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
31   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
32   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
33   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
34   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
35   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
36   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
37   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38   *
39   * ====================================================================
40   * This software consists of voluntary contributions made by many
41   * individuals on behalf of the Jaxen Project and was originally
42   * created by bob mcwhirter <bob@werken.com> and
43   * James Strachan <jstrachan@apache.org>.  For more information on the
44   * Jaxen Project, please see <http://www.jaxen.org/>.
45   *
46   * $Id$
47   */
48  
49  package org.jaxen.saxpath;
50  
51  
52  /**
53   * Represents a syntax error in an XPath expression.
54   * This is a compile-time error that is detectable irrespective of 
55   * the context in which the XPath expression is evaluated.
56   */
57  public class XPathSyntaxException extends SAXPathException
58  {
59  
60      private static final long serialVersionUID = 3567675610742422397L;
61      private String xpath;
62      private int    position;
63      private final static String lineSeparator = System.getProperty("line.separator");
64  
65      /**
66       * Creates a new XPathSyntaxException.
67       * 
68       * @param xpath the incorrect XPath expression 
69       * @param position the index of the character at which the syntax error was detected
70       * @param message the detail message
71       */
72      public XPathSyntaxException(String xpath,
73                                  int position,
74                                  String message)
75      {
76          super( message );
77          this.position = position;
78          this.xpath    = xpath;
79      }
80  
81      /**
82       * <p>
83       * Returns the index of the character at which the syntax error was detected
84       * in the XPath expression.
85       * </p>
86       * 
87       * @return the character index in the XPath expression  
88       *     at which the syntax error was detected
89       */
90      public int getPosition()
91      {
92          return this.position;
93      }
94  
95      /**
96       * <p>
97       * Returns the syntactically incorrect XPath expression.
98       * </p>
99       * 
100      * @return the syntactically incorrect XPath expression
101      */
102     public String getXPath()
103     {
104         return this.xpath;
105     }
106 
107     public String toString()
108     {
109         return getClass() + ": " + getXPath() + ": " + getPosition() + ": " + getMessage();
110     }
111 
112     /**
113      * <p>
114      * Returns a string in the form <code>"   ^"</code> which, when placed on the line
115      * below the XPath expression in a monospaced font, should point to the
116      * location of the error.
117      * </p>
118      * 
119      * @return the position marker 
120      */
121     private String getPositionMarker()
122     {
123         int pos = getPosition();
124         StringBuffer buf = new StringBuffer(pos+1);
125         for ( int i = 0 ; i < pos ; ++i )
126         {
127             buf.append(" ");
128         }
129 
130         buf.append("^");
131 
132         return buf.toString();
133         
134     }
135 
136     /**
137      * <p>
138      * Returns a long formatted description of the error,
139      * including line breaks.
140      * </p>
141      * 
142      * @return a longer description of the error on multiple lines
143      */
144     public String getMultilineMessage()
145     {
146         StringBuffer buf = new StringBuffer();
147 
148         buf.append( getMessage() );
149         buf.append( lineSeparator );
150         buf.append( getXPath() );
151         buf.append( lineSeparator );
152 
153         buf.append( getPositionMarker() );
154 
155         return buf.toString();
156     }
157 
158 }