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
26package java.util.regex;
27
28import 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
40public 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}
124