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