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: * $Header:$
018: */
019: package org.apache.beehive.netui.script.el.parser;
020:
021: import org.apache.beehive.netui.util.internal.InternalStringBuilder;
022:
023: /**
024: * This exception is thrown when parse errors are encountered.
025: * You can explicitly create objects of this exception type by
026: * calling the method generateParseException in the generated
027: * parser.
028: * <p/>
029: * You can modify this class to customize your error reporting
030: * mechanisms so long as you retain the public fields.
031: */
032: public class ParseException extends Exception {
033:
034: /**
035: * This constructor is used by the method "generateParseException"
036: * in the generated parser. Calling this constructor generates
037: * a new object of this type with the fields "currentToken",
038: * "expectedTokenSequences", and "tokenImage" set. The boolean
039: * flag "specialConstructor" is also set to true to indicate that
040: * this constructor was used to create this object.
041: * This constructor calls its super class with the empty string
042: * to force the "toString" method of parent class "Throwable" to
043: * print the error message in the form:
044: * ParseException: <result of getMessage>
045: */
046: public ParseException(Token currentTokenVal,
047: int[][] expectedTokenSequencesVal, String[] tokenImageVal) {
048: super ("");
049: specialConstructor = true;
050: currentToken = currentTokenVal;
051: expectedTokenSequences = expectedTokenSequencesVal;
052: tokenImage = tokenImageVal;
053: }
054:
055: /**
056: * The following constructors are for use by you for whatever
057: * purpose you can think of. Constructing the exception in this
058: * manner makes the exception behave in the normal way - i.e., as
059: * documented in the class "Throwable". The fields "errorToken",
060: * "expectedTokenSequences", and "tokenImage" do not contain
061: * relevant information. The JavaCC generated code does not use
062: * these constructors.
063: */
064:
065: public ParseException() {
066: super ();
067: specialConstructor = false;
068: }
069:
070: public ParseException(String message) {
071: super (message);
072: specialConstructor = false;
073: }
074:
075: /**
076: * This variable determines which constructor was used to create
077: * this object and thereby affects the semantics of the
078: * "getMessage" method (see below).
079: */
080: protected boolean specialConstructor;
081:
082: /**
083: * This is the last token that has been consumed successfully. If
084: * this object has been created due to a parse error, the token
085: * followng this token will (therefore) be the first error token.
086: */
087: public Token currentToken;
088:
089: /**
090: * Each entry in this array is an array of integers. Each array
091: * of integers represents a sequence of tokens (by their ordinal
092: * values) that is expected at this point of the parse.
093: */
094: public int[][] expectedTokenSequences;
095:
096: /**
097: * This is a reference to the "tokenImage" array of the generated
098: * parser within which the parse error occurred. This array is
099: * defined in the generated ...Constants interface.
100: */
101: public String[] tokenImage;
102:
103: /**
104: * This method has the standard behavior when this object has been
105: * created using the standard constructors. Otherwise, it uses
106: * "currentToken" and "expectedTokenSequences" to generate a parse
107: * error message and returns it. If this object has been created
108: * due to a parse error, and you do not catch it (it gets thrown
109: * from the parser), then this method is called during the printing
110: * of the final stack trace, and hence the correct error message
111: * gets displayed.
112: */
113: public String getMessage() {
114: if (!specialConstructor) {
115: return super .getMessage();
116: }
117: String expected = "";
118: int maxSize = 0;
119: for (int i = 0; i < expectedTokenSequences.length; i++) {
120: if (maxSize < expectedTokenSequences[i].length) {
121: maxSize = expectedTokenSequences[i].length;
122: }
123: for (int j = 0; j < expectedTokenSequences[i].length; j++) {
124: expected += tokenImage[expectedTokenSequences[i][j]]
125: + " ";
126: }
127: if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
128: expected += "...";
129: }
130: expected += eol + " ";
131: }
132: String retval = "Encountered \"";
133: Token tok = currentToken.next;
134: for (int i = 0; i < maxSize; i++) {
135: if (i != 0)
136: retval += " ";
137: if (tok.kind == 0) {
138: retval += tokenImage[0];
139: break;
140: }
141: retval += add_escapes(tok.image);
142: tok = tok.next;
143: }
144: retval += "\" at line " + currentToken.next.beginLine
145: + ", column " + currentToken.next.beginColumn;
146: retval += "." + eol;
147: if (expectedTokenSequences.length == 1) {
148: retval += "Was expecting:" + eol + " ";
149: } else {
150: retval += "Was expecting one of:" + eol + " ";
151: }
152: retval += expected;
153: return retval;
154: }
155:
156: /**
157: * The end of line string for this machine.
158: */
159: protected String eol = System.getProperty("line.separator", "\n");
160:
161: /**
162: * Used to convert raw characters to their escaped version
163: * when these raw version cannot be used as part of an ASCII
164: * string literal.
165: */
166: protected String add_escapes(String str) {
167: InternalStringBuilder retval = new InternalStringBuilder();
168: char ch;
169: for (int i = 0; i < str.length(); i++) {
170: switch (str.charAt(i)) {
171: case 0:
172: continue;
173: case '\b':
174: retval.append("\\b");
175: continue;
176: case '\t':
177: retval.append("\\t");
178: continue;
179: case '\n':
180: retval.append("\\n");
181: continue;
182: case '\f':
183: retval.append("\\f");
184: continue;
185: case '\r':
186: retval.append("\\r");
187: continue;
188: case '\"':
189: retval.append("\\\"");
190: continue;
191: case '\'':
192: retval.append("\\\'");
193: continue;
194: case '\\':
195: retval.append("\\\\");
196: continue;
197: default:
198: if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
199: String s = "0000" + Integer.toString(ch, 16);
200: retval.append("\\u"
201: + s.substring(s.length() - 4, s.length()));
202: } else {
203: retval.append(ch);
204: }
205: continue;
206: }
207: }
208: return retval.toString();
209: }
210:
211: }
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