001 /* Generated By:JavaCC: Do not edit this line. ParseException.java Version 3.0 */
002 package net.hydromatic.clapham.parser.bnf;
003
004 /**
005 * This exception is thrown when parse errors are encountered.
006 * You can explicitly create objects of this exception type by
007 * calling the method generateParseException in the generated
008 * parser.
009 *
010 * You can modify this class to customize your error reporting
011 * mechanisms so long as you retain the public fields.
012 */
013 public class ParseException extends Exception {
014
015 /**
016 * This constructor is used by the method "generateParseException"
017 * in the generated parser. Calling this constructor generates
018 * a new object of this type with the fields "currentToken",
019 * "expectedTokenSequences", and "tokenImage" set. The boolean
020 * flag "specialConstructor" is also set to true to indicate that
021 * this constructor was used to create this object.
022 * This constructor calls its super class with the empty string
023 * to force the "toString" method of parent class "Throwable" to
024 * print the error message in the form:
025 * ParseException: <result of getMessage>
026 */
027 public ParseException(Token currentTokenVal,
028 int[][] expectedTokenSequencesVal,
029 String[] tokenImageVal
030 )
031 {
032 super("");
033 specialConstructor = true;
034 currentToken = currentTokenVal;
035 expectedTokenSequences = expectedTokenSequencesVal;
036 tokenImage = tokenImageVal;
037 }
038
039 /**
040 * The following constructors are for use by you for whatever
041 * purpose you can think of. Constructing the exception in this
042 * manner makes the exception behave in the normal way - i.e., as
043 * documented in the class "Throwable". The fields "errorToken",
044 * "expectedTokenSequences", and "tokenImage" do not contain
045 * relevant information. The JavaCC generated code does not use
046 * these constructors.
047 */
048
049 public ParseException() {
050 super();
051 specialConstructor = false;
052 }
053
054 public ParseException(String message) {
055 super(message);
056 specialConstructor = false;
057 }
058
059 /**
060 * This variable determines which constructor was used to create
061 * this object and thereby affects the semantics of the
062 * "getMessage" method (see below).
063 */
064 protected boolean specialConstructor;
065
066 /**
067 * This is the last token that has been consumed successfully. If
068 * this object has been created due to a parse error, the token
069 * followng this token will (therefore) be the first error token.
070 */
071 public Token currentToken;
072
073 /**
074 * Each entry in this array is an array of integers. Each array
075 * of integers represents a sequence of tokens (by their ordinal
076 * values) that is expected at this point of the parse.
077 */
078 public int[][] expectedTokenSequences;
079
080 /**
081 * This is a reference to the "tokenImage" array of the generated
082 * parser within which the parse error occurred. This array is
083 * defined in the generated ...Constants interface.
084 */
085 public String[] tokenImage;
086
087 /**
088 * This method has the standard behavior when this object has been
089 * created using the standard constructors. Otherwise, it uses
090 * "currentToken" and "expectedTokenSequences" to generate a parse
091 * error message and returns it. If this object has been created
092 * due to a parse error, and you do not catch it (it gets thrown
093 * from the parser), then this method is called during the printing
094 * of the final stack trace, and hence the correct error message
095 * gets displayed.
096 */
097 public String getMessage() {
098 if (!specialConstructor) {
099 return super.getMessage();
100 }
101 StringBuffer expected = new StringBuffer();
102 int maxSize = 0;
103 for (int i = 0; i < expectedTokenSequences.length; i++) {
104 if (maxSize < expectedTokenSequences[i].length) {
105 maxSize = expectedTokenSequences[i].length;
106 }
107 for (int j = 0; j < expectedTokenSequences[i].length; j++) {
108 expected.append(tokenImage[expectedTokenSequences[i][j]]).append(" ");
109 }
110 if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
111 expected.append("...");
112 }
113 expected.append(eol).append(" ");
114 }
115 String retval = "Encountered \"";
116 Token tok = currentToken.next;
117 for (int i = 0; i < maxSize; i++) {
118 if (i != 0) retval += " ";
119 if (tok.kind == 0) {
120 retval += tokenImage[0];
121 break;
122 }
123 retval += add_escapes(tok.image);
124 tok = tok.next;
125 }
126 retval += "\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn;
127 retval += "." + eol;
128 if (expectedTokenSequences.length == 1) {
129 retval += "Was expecting:" + eol + " ";
130 } else {
131 retval += "Was expecting one of:" + eol + " ";
132 }
133 retval += expected.toString();
134 return retval;
135 }
136
137 /**
138 * The end of line string for this machine.
139 */
140 protected String eol = System.getProperty("line.separator", "\n");
141
142 /**
143 * Used to convert raw characters to their escaped version
144 * when these raw version cannot be used as part of an ASCII
145 * string literal.
146 */
147 protected String add_escapes(String str) {
148 StringBuffer retval = new StringBuffer();
149 char ch;
150 for (int i = 0; i < str.length(); i++) {
151 switch (str.charAt(i))
152 {
153 case 0 :
154 continue;
155 case '\b':
156 retval.append("\\b");
157 continue;
158 case '\t':
159 retval.append("\\t");
160 continue;
161 case '\n':
162 retval.append("\\n");
163 continue;
164 case '\f':
165 retval.append("\\f");
166 continue;
167 case '\r':
168 retval.append("\\r");
169 continue;
170 case '\"':
171 retval.append("\\\"");
172 continue;
173 case '\'':
174 retval.append("\\\'");
175 continue;
176 case '\\':
177 retval.append("\\\\");
178 continue;
179 default:
180 if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
181 String s = "0000" + Integer.toString(ch, 16);
182 retval.append("\\u" + s.substring(s.length() - 4, s.length()));
183 } else {
184 retval.append(ch);
185 }
186 continue;
187 }
188 }
189 return retval.toString();
190 }
191
192 }