1
2
3 /***************************************************************************************
4 * Copyright (c) Jonas BonŽr, Alexandre Vasseur. All rights reserved. *
5 * http://aspectwerkz.codehaus.org *
6 * ---------------------------------------------------------------------------------- *
7 * The software in this package is published under the terms of the LGPL license *
8 * a copy of which has been included with this distribution in the license.txt file. *
9 **************************************************************************************/
10 package org.codehaus.aspectwerkz.annotation.expression.ast;
11
12 /***
13 * This exception is thrown when parse errors are encountered. You can explicitly create objects of this exception type
14 * by calling the method generateParseException in the generated parser. <p/>You can modify this class to customize your
15 * error reporting mechanisms so long as you retain the public fields.
16 */
17 public class ParseException extends Exception {
18 /***
19 * This variable determines which constructor was used to create this object and thereby affects the semantics of
20 * the "getMessage" method (see below).
21 */
22 protected boolean specialConstructor;
23
24 /***
25 * This is the last token that has been consumed successfully. If this object has been created due to a parse error,
26 * the token followng this token will (therefore) be the first error token.
27 */
28 public Token currentToken;
29
30 /***
31 * Each entry in this array is an array of integers. Each array of integers represents a sequence of tokens (by
32 * their ordinal values) that is expected at this point of the parse.
33 */
34 public int[][] expectedTokenSequences;
35
36 /***
37 * This is a reference to the "tokenImage" array of the generated parser within which the parse error occurred. This
38 * array is defined in the generated ...Constants interface.
39 */
40 public String[] tokenImage;
41
42 /***
43 * The end of line string for this machine.
44 */
45 protected String eol = System.getProperty("line.separator", "\n");
46
47 /***
48 * This constructor is used by the method "generateParseException" in the generated parser. Calling this constructor
49 * generates a new object of this type with the fields "currentToken", "expectedTokenSequences", and "tokenImage"
50 * set. The boolean flag "specialConstructor" is also set to true to indicate that this constructor was used to
51 * create this object. This constructor calls its super class with the empty string to force the "toString" method
52 * of parent class "Throwable" to print the error message in the form: ParseException: <result of getMessage>
53 */
54 public ParseException(Token currentTokenVal, int[][] expectedTokenSequencesVal, String[] tokenImageVal) {
55 super("");
56 specialConstructor = true;
57 currentToken = currentTokenVal;
58 expectedTokenSequences = expectedTokenSequencesVal;
59 tokenImage = tokenImageVal;
60 }
61
62 /***
63 * The following constructors are for use by you for whatever purpose you can think of. Constructing the exception
64 * in this manner makes the exception behave in the normal way - i.e., as documented in the class "Throwable". The
65 * fields "errorToken", "expectedTokenSequences", and "tokenImage" do not contain relevant information. The JavaCC
66 * generated code does not use these constructors.
67 */
68 public ParseException() {
69 super();
70 specialConstructor = false;
71 }
72
73 public ParseException(String message) {
74 super(message);
75 specialConstructor = false;
76 }
77
78 /***
79 * This method has the standard behavior when this object has been created using the standard constructors.
80 * Otherwise, it uses "currentToken" and "expectedTokenSequences" to generate a parse error message and returns it.
81 * If this object has been created due to a parse error, and you do not catch it (it gets thrown from the parser),
82 * then this method is called during the printing of the final stack trace, and hence the correct error message gets
83 * displayed.
84 */
85 public String getMessage() {
86 if (!specialConstructor) {
87 return super.getMessage();
88 }
89 String expected = "";
90 int maxSize = 0;
91 for (int i = 0; i < expectedTokenSequences.length; i++) {
92 if (maxSize < expectedTokenSequences[i].length) {
93 maxSize = expectedTokenSequences[i].length;
94 }
95 for (int j = 0; j < expectedTokenSequences[i].length; j++) {
96 expected += (tokenImage[expectedTokenSequences[i][j]] + " ");
97 }
98 if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
99 expected += "...";
100 }
101 expected += (eol + " ");
102 }
103 String retval = "Encountered \"";
104 Token tok = currentToken.next;
105 for (int i = 0; i < maxSize; i++) {
106 if (i != 0) {
107 retval += " ";
108 }
109 if (tok.kind == 0) {
110 retval += tokenImage[0];
111 break;
112 }
113 retval += add_escapes(tok.image);
114 tok = tok.next;
115 }
116 retval += ("\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn);
117 retval += ("." + eol);
118 if (expectedTokenSequences.length == 1) {
119 retval += ("Was expecting:" + eol + " ");
120 } else {
121 retval += ("Was expecting one of:" + eol + " ");
122 }
123 retval += expected;
124 return retval;
125 }
126
127 /***
128 * Used to convert raw characters to their escaped version when these raw version cannot be used as part of an ASCII
129 * string literal.
130 */
131 protected String add_escapes(String str) {
132 StringBuffer retval = new StringBuffer();
133 char ch;
134 for (int i = 0; i < str.length(); i++) {
135 switch (str.charAt(i)) {
136 case 0:
137 continue;
138 case '\b':
139 retval.append("//b");
140 continue;
141 case '\t':
142 retval.append("//t");
143 continue;
144 case '\n':
145 retval.append("//n");
146 continue;
147 case '\f':
148 retval.append("//f");
149 continue;
150 case '\r':
151 retval.append("//r");
152 continue;
153 case '\"':
154 retval.append("//\"");
155 continue;
156 case '\'':
157 retval.append("//\'");
158 continue;
159 case '//':
160 retval.append("////");
161 continue;
162 default:
163 if (((ch = str.charAt(i)) < 0x20) || (ch > 0x7e)) {
164 String s = "0000" + Integer.toString(ch, 16);
165 retval.append("//u" + s.substring(s.length() - 4, s.length()));
166 } else {
167 retval.append(ch);
168 }
169 continue;
170 }
171 }
172 return retval.toString();
173 }
174 }