1 /*
   2  * Copyright (c) 1999, 2018, 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 /**
  29  * Unchecked exception thrown to indicate a syntax error in a
  30  * regular-expression pattern.
  31  *
  32  * @author  unascribed
  33  * @since 1.4
  34  * @spec JSR-51
  35  */
  36 
  37 public class PatternSyntaxException
  38     extends IllegalArgumentException
  39 {
  40     @java.io.Serial
  41     private static final long serialVersionUID = -3864639126226059218L;
  42 
  43     private final String desc;
  44     private final String pattern;
  45     private final int index;
  46 
  47     /**
  48      * Constructs a new instance of this class.
  49      *
  50      * @param  desc
  51      *         A description of the error
  52      *
  53      * @param  regex
  54      *         The erroneous pattern
  55      *
  56      * @param  index
  57      *         The approximate index in the pattern of the error,
  58      *         or {@code -1} if the index is not known
  59      */
  60     public PatternSyntaxException(String desc, String regex, int index) {
  61         this.desc = desc;
  62         this.pattern = regex;
  63         this.index = index;
  64     }
  65 
  66     /**
  67      * Retrieves the error index.
  68      *
  69      * @return  The approximate index in the pattern of the error,
  70      *         or {@code -1} if the index is not known
  71      */
  72     public int getIndex() {
  73         return index;
  74     }
  75 
  76     /**
  77      * Retrieves the description of the error.
  78      *
  79      * @return  The description of the error
  80      */
  81     public String getDescription() {
  82         return desc;
  83     }
  84 
  85     /**
  86      * Retrieves the erroneous regular-expression pattern.
  87      *
  88      * @return  The erroneous pattern
  89      */
  90     public String getPattern() {
  91         return pattern;
  92     }
  93 
  94     /**
  95      * Returns a multi-line string containing the description of the syntax
  96      * error and its index, the erroneous regular-expression pattern, and a
  97      * visual indication of the error index within the pattern.
  98      *
  99      * @return  The full detail message
 100      */
 101     public String getMessage() {
 102         StringBuilder sb = new StringBuilder();
 103         sb.append(desc);
 104         if (index >= 0) {
 105             sb.append(" near index ");
 106             sb.append(index);
 107         }
 108         sb.append(System.lineSeparator());
 109         sb.append(pattern);
 110         if (index >= 0 && pattern != null && index < pattern.length()) {
 111             sb.append(System.lineSeparator());
 112             for (int i = 0; i < index; i++) sb.append(' ');
 113             sb.append('^');
 114         }
 115         return sb.toString();
 116     }
 117 
 118 }