001: /*
002: * Licensed to the Apache Software Foundation (ASF) under one or more
003: * contributor license agreements. See the NOTICE file distributed with
004: * this work for additional information regarding copyright ownership.
005: * The ASF licenses this file to You under the Apache License, Version 2.0
006: * (the "License"); you may not use this file except in compliance with
007: * the License. You may obtain a copy of the License at
008: *
009: * http://www.apache.org/licenses/LICENSE-2.0
010: *
011: * Unless required by applicable law or agreed to in writing, software
012: * distributed under the License is distributed on an "AS IS" BASIS,
013: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014: * See the License for the specific language governing permissions and
015: * limitations under the License.
016: */
017: package org.apache.cocoon.components.xpointer.parser;
018:
019: /**
020: * This exception is thrown when parse errors are encountered.
021: * You can explicitly create objects of this exception type by
022: * calling the method generateParseException in the generated
023: * parser.
024: *
025: * You can modify this class to customize your error reporting
026: * mechanisms so long as you retain the public fields.
027: */
028: public class ParseException extends Exception {
029:
030: /**
031: * This constructor is used by the method "generateParseException"
032: * in the generated parser. Calling this constructor generates
033: * a new object of this type with the fields "currentToken",
034: * "expectedTokenSequences", and "tokenImage" set. The boolean
035: * flag "specialConstructor" is also set to true to indicate that
036: * this constructor was used to create this object.
037: * This constructor calls its super class with the empty string
038: * to force the "toString" method of parent class "Throwable" to
039: * print the error message in the form:
040: * ParseException: <result of getMessage>
041: */
042: public ParseException(Token currentTokenVal,
043: int[][] expectedTokenSequencesVal, String[] tokenImageVal) {
044: super ("");
045: specialConstructor = true;
046: currentToken = currentTokenVal;
047: expectedTokenSequences = expectedTokenSequencesVal;
048: tokenImage = tokenImageVal;
049: }
050:
051: /**
052: * The following constructors are for use by you for whatever
053: * purpose you can think of. Constructing the exception in this
054: * manner makes the exception behave in the normal way - i.e., as
055: * documented in the class "Throwable". The fields "errorToken",
056: * "expectedTokenSequences", and "tokenImage" do not contain
057: * relevant information. The JavaCC generated code does not use
058: * these constructors.
059: */
060:
061: public ParseException() {
062: super ();
063: specialConstructor = false;
064: }
065:
066: public ParseException(String message) {
067: super (message);
068: specialConstructor = false;
069: }
070:
071: /**
072: * This variable determines which constructor was used to create
073: * this object and thereby affects the semantics of the
074: * "getMessage" method (see below).
075: */
076: protected boolean specialConstructor;
077:
078: /**
079: * This is the last token that has been consumed successfully. If
080: * this object has been created due to a parse error, the token
081: * followng this token will (therefore) be the first error token.
082: */
083: public Token currentToken;
084:
085: /**
086: * Each entry in this array is an array of integers. Each array
087: * of integers represents a sequence of tokens (by their ordinal
088: * values) that is expected at this point of the parse.
089: */
090: public int[][] expectedTokenSequences;
091:
092: /**
093: * This is a reference to the "tokenImage" array of the generated
094: * parser within which the parse error occurred. This array is
095: * defined in the generated ...Constants interface.
096: */
097: public String[] tokenImage;
098:
099: /**
100: * This method has the standard behavior when this object has been
101: * created using the standard constructors. Otherwise, it uses
102: * "currentToken" and "expectedTokenSequences" to generate a parse
103: * error message and returns it. If this object has been created
104: * due to a parse error, and you do not catch it (it gets thrown
105: * from the parser), then this method is called during the printing
106: * of the final stack trace, and hence the correct error message
107: * gets displayed.
108: */
109: public String getMessage() {
110: if (!specialConstructor) {
111: return super .getMessage();
112: }
113: StringBuffer expected = new StringBuffer();
114: int maxSize = 0;
115: for (int i = 0; i < expectedTokenSequences.length; i++) {
116: if (maxSize < expectedTokenSequences[i].length) {
117: maxSize = expectedTokenSequences[i].length;
118: }
119: for (int j = 0; j < expectedTokenSequences[i].length; j++) {
120: expected
121: .append(tokenImage[expectedTokenSequences[i][j]]);
122: expected.append(" ");
123: }
124: if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
125: expected.append("...");
126: }
127: expected.append(eol);
128: expected.append(" ");
129: }
130: StringBuffer retval = new StringBuffer("Encountered \"");
131: Token tok = currentToken.next;
132: for (int i = 0; i < maxSize; i++) {
133: if (i != 0)
134: retval.append(" ");
135: if (tok.kind == 0) {
136: retval.append(tokenImage[0]);
137: break;
138: }
139: retval.append(add_escapes(tok.image));
140: tok = tok.next;
141: }
142: retval.append("\" at line ");
143: retval.append(currentToken.next.beginLine);
144: retval.append(", column ");
145: retval.append(currentToken.next.beginColumn);
146: retval.append(".");
147: retval.append(eol);
148: retval.append("Was expecting");
149: if (expectedTokenSequences.length != 1) {
150: retval.append(" one of");
151: }
152: retval.append(":");
153: retval.append(eol);
154: retval.append(" ");
155: retval.append(expected);
156: return retval.toString();
157: }
158:
159: /**
160: * The end of line string for this machine.
161: */
162: protected String eol = System.getProperty("line.separator", "\n");
163:
164: /**
165: * Used to convert raw characters to their escaped version
166: * when these raw version cannot be used as part of an ASCII
167: * string literal.
168: */
169: protected String add_escapes(String str) {
170: StringBuffer retval = new StringBuffer();
171: char ch;
172: for (int i = 0; i < str.length(); i++) {
173: switch (str.charAt(i)) {
174: case 0:
175: continue;
176: case '\b':
177: retval.append("\\b");
178: continue;
179: case '\t':
180: retval.append("\\t");
181: continue;
182: case '\n':
183: retval.append("\\n");
184: continue;
185: case '\f':
186: retval.append("\\f");
187: continue;
188: case '\r':
189: retval.append("\\r");
190: continue;
191: case '\"':
192: retval.append("\\\"");
193: continue;
194: case '\'':
195: retval.append("\\\'");
196: continue;
197: case '\\':
198: retval.append("\\\\");
199: continue;
200: default:
201: if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
202: String s = "0000" + Integer.toString(ch, 16);
203: retval.append("\\u"
204: + s.substring(s.length() - 4, s.length()));
205: } else {
206: retval.append(ch);
207: }
208: continue;
209: }
210: }
211: return retval.toString();
212: }
213:
214: }
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