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17 package org.apache.commons.jexl.parser;
18
19 /***
20 * This exception is thrown when parse errors are encountered. You can
21 * explicitly create objects of this exception type by calling the method
22 * generateParseException in the generated parser.
23 *
24 * You can modify this class to customize your error reporting mechanisms so
25 * long as you retain the public fields.
26 */
27 public class ParseException extends Exception {
28
29 /*** serialization version id jdk13 generated. */
30 static final long serialVersionUID = 654626477565941968L;
31
32 /***
33 * This constructor is used by the method "generateParseException" in the
34 * generated parser. Calling this constructor generates a new object of this
35 * type with the fields "currentToken", "expectedTokenSequences", and
36 * "tokenImage" set. The boolean flag "specialConstructor" is also set to
37 * true to indicate that this constructor was used to create this object.
38 * This constructor calls its super class with the empty string to force the
39 * "toString" method of parent class "Throwable" to print the error message
40 * in the form: ParseException: (result of getMessage)
41 */
42 public ParseException(Token currentTokenVal, int[][] expectedTokenSequencesVal, String[] tokenImageVal) {
43 super("");
44 specialConstructor = true;
45 currentToken = currentTokenVal;
46 expectedTokenSequences = expectedTokenSequencesVal;
47 tokenImage = tokenImageVal;
48 }
49
50 /***
51 * The following constructors are for use by you for whatever purpose you
52 * can think of. Constructing the exception in this manner makes the
53 * exception behave in the normal way - i.e., as documented in the class
54 * "Throwable". The fields "errorToken", "expectedTokenSequences", and
55 * "tokenImage" do not contain relevant information. The JavaCC generated
56 * code does not use these constructors.
57 */
58
59 public ParseException() {
60 super();
61 specialConstructor = false;
62 }
63
64 public ParseException(String message) {
65 super(message);
66 specialConstructor = false;
67 }
68
69 /***
70 * This variable determines which constructor was used to create this object
71 * and thereby affects the semantics of the "getMessage" method (see below).
72 */
73 protected boolean specialConstructor;
74
75 /***
76 * This is the last token that has been consumed successfully. If this
77 * object has been created due to a parse error, the token followng this
78 * token will (therefore) be the first error token.
79 */
80 public Token currentToken;
81
82 /***
83 * Each entry in this array is an array of integers. Each array of integers
84 * represents a sequence of tokens (by their ordinal values) that is
85 * expected at this point of the parse.
86 */
87 public int[][] expectedTokenSequences;
88
89 /***
90 * This is a reference to the "tokenImage" array of the generated parser
91 * within which the parse error occurred. This array is defined in the
92 * generated ...Constants interface.
93 */
94 public String[] tokenImage;
95
96 /***
97 * This method has the standard behavior when this object has been created
98 * using the standard constructors. Otherwise, it uses "currentToken" and
99 * "expectedTokenSequences" to generate a parse error message and returns
100 * it. If this object has been created due to a parse error, and you do not
101 * catch it (it gets thrown from the parser), then this method is called
102 * during the printing of the final stack trace, and hence the correct error
103 * message gets displayed.
104 */
105 public String getMessage() {
106 if (!specialConstructor) {
107 return super.getMessage();
108 }
109 String expected = "";
110 int maxSize = 0;
111 for (int i = 0; i < expectedTokenSequences.length; i++) {
112 if (maxSize < expectedTokenSequences[i].length) {
113 maxSize = expectedTokenSequences[i].length;
114 }
115 for (int j = 0; j < expectedTokenSequences[i].length; j++) {
116 expected += tokenImage[expectedTokenSequences[i][j]] + " ";
117 }
118 if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
119 expected += "...";
120 }
121 expected += eol + " ";
122 }
123 String retval = "Encountered \"";
124 Token tok = currentToken.next;
125 for (int i = 0; i < maxSize; i++) {
126 if (i != 0)
127 retval += " ";
128 if (tok.kind == 0) {
129 retval += tokenImage[0];
130 break;
131 }
132 retval += add_escapes(tok.image);
133 tok = tok.next;
134 }
135 retval += "\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn;
136 retval += "." + eol;
137 if (expectedTokenSequences.length == 1) {
138 retval += "Was expecting:" + eol + " ";
139 } else {
140 retval += "Was expecting one of:" + eol + " ";
141 }
142 retval += expected;
143 return retval;
144 }
145
146 /***
147 * The end of line string for this machine.
148 */
149 protected String eol = System.getProperty("line.separator", "\n");
150
151 /***
152 * Used to convert raw characters to their escaped version when these raw
153 * version cannot be used as part of an ASCII string literal.
154 */
155 protected String add_escapes(String str) {
156 StringBuffer retval = new StringBuffer();
157 char ch;
158 for (int i = 0; i < str.length(); i++) {
159 switch (str.charAt(i)) {
160 case 0:
161 continue;
162 case '\b':
163 retval.append("//b");
164 continue;
165 case '\t':
166 retval.append("//t");
167 continue;
168 case '\n':
169 retval.append("//n");
170 continue;
171 case '\f':
172 retval.append("//f");
173 continue;
174 case '\r':
175 retval.append("//r");
176 continue;
177 case '\"':
178 retval.append("//\"");
179 continue;
180 case '\'':
181 retval.append("//\'");
182 continue;
183 case '//':
184 retval.append("////");
185 continue;
186 default:
187 if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
188 String s = "0000" + Integer.toString(ch, 16);
189 retval.append("//u").append(s.substring(s.length() - 4, s.length()));
190 } else {
191 retval.append(ch);
192 }
193 continue;
194 }
195 }
196 return retval.toString();
197 }
198
199 }