1 /*
   2  * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util.regex;
  27 
  28 import sun.security.action.GetPropertyAction;
  29 
  30 
  31 /**
  32  * Unchecked exception thrown to indicate a syntax error in a
  33  * regular-expression pattern.
  34  *
  35  * @author  unascribed
  36  * @since 1.4
  37  * @spec JSR-51
  38  */
  39 
  40 public class PatternSyntaxException
  41     extends IllegalArgumentException
  42 {
  43     private static final long serialVersionUID = -3864639126226059218L;
  44 
  45     private final String desc;
  46     private final String pattern;
  47     private final int index;
  48 
  49     /**
  50      * Constructs a new instance of this class.
  51      *
  52      * @param  desc
  53      *         A description of the error
  54      *
  55      * @param  regex
  56      *         The erroneous pattern
  57      *
  58      * @param  index
  59      *         The approximate index in the pattern of the error,
  60      *         or {@code -1} if the index is not known
  61      */
  62     public PatternSyntaxException(String desc, String regex, int index) {
  63         this.desc = desc;
  64         this.pattern = regex;
  65         this.index = index;
  66     }
  67 
  68     /**
  69      * Retrieves the error index.
  70      *
  71      * @return  The approximate index in the pattern of the error,
  72      *         or {@code -1} if the index is not known
  73      */
  74     public int getIndex() {
  75         return index;
  76     }
  77 
  78     /**
  79      * Retrieves the description of the error.
  80      *
  81      * @return  The description of the error
  82      */
  83     public String getDescription() {
  84         return desc;
  85     }
  86 
  87     /**
  88      * Retrieves the erroneous regular-expression pattern.
  89      *
  90      * @return  The erroneous pattern
  91      */
  92     public String getPattern() {
  93         return pattern;
  94     }
  95 
  96     private static final String nl =
  97             GetPropertyAction.privilegedGetProperty("line.separator");
  98 
  99     /**
 100      * Returns a multi-line string containing the description of the syntax
 101      * error and its index, the erroneous regular-expression pattern, and a
 102      * visual indication of the error index within the pattern.
 103      *
 104      * @return  The full detail message
 105      */
 106     public String getMessage() {
 107         StringBuilder sb = new StringBuilder();
 108         sb.append(desc);
 109         if (index >= 0) {
 110             sb.append(" near index ");
 111             sb.append(index);
 112         }
 113         sb.append(nl);
 114         sb.append(pattern);
 115         if (index >= 0) {
 116             sb.append(nl);
 117             for (int i = 0; i < index; i++) sb.append(' ');
 118             sb.append('^');
 119         }
 120         return sb.toString();
 121     }
 122 
 123 }