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/*****************************************************************************
JEP - Java Expression Parser
JEP is a Java package for parsing and evaluating mathematical
expressions. It currently supports user defined variables,
constant, and functions. A number of common mathematical
functions and constants are included.
JEPLite is a simplified version of JEP.
JEP Author: Nathan Funk
JEPLite Author: Stephen "Cheffo" Kolaroff
JEP Copyright (C) 2001 Nathan Funk
JEPLite Copyright (C) 2002 Stefan Kolarov
JEPLite is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
JEPLite is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with JEPLite; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/**
* This exception is thrown when parse errors are encountered.
* You can explicitly create objects of this exception type by
* calling the method generateParseException in the generated
* parser.
*
* You can modify this class to customize your error reporting
* mechanisms so long as you retain the public fields.
*/
package org.cheffo.jeplite;
public class ParseException extends Exception {
/**
* This constructor is used by the method "generateParseException"
* in the generated parser. Calling this constructor generates
* a new object of this type with the fields "currentToken",
* "expectedTokenSequences", and "tokenImage" set. The boolean
* flag "specialConstructor" is also set to true to indicate that
* this constructor was used to create this object.
* This constructor calls its super class with the empty string
* to force the "toString" method of parent class "Throwable" to
* print the error message in the form:
* ParseException: <result of getMessage>
*/
public ParseException(Token currentTokenVal,
int[][] expectedTokenSequencesVal,
String[] tokenImageVal
)
{
super("");
specialConstructor = true;
currentToken = currentTokenVal;
expectedTokenSequences = expectedTokenSequencesVal;
tokenImage = tokenImageVal;
}
/**
* The following constructors are for use by you for whatever
* purpose you can think of. Constructing the exception in this
* manner makes the exception behave in the normal way - i.e., as
* documented in the class "Throwable". The fields "errorToken",
* "expectedTokenSequences", and "tokenImage" do not contain
* relevant information. The JavaCC generated code does not use
* these constructors.
*/
public ParseException() {
super();
specialConstructor = false;
}
public ParseException(String message) {
super(message);
specialConstructor = false;
}
public ParseException(Token currentTokenVal, String message) {
super(message);
specialConstructor = false;
currentToken = currentTokenVal;
}
/**
* This variable determines which constructor was used to create
* this object and thereby affects the semantics of the
* "getMessage" method (see below).
*/
protected boolean specialConstructor;
/**
* This is the last token that has been consumed successfully. If
* this object has been created due to a parse error, the token
* followng this token will (therefore) be the first error token.
*/
public Token currentToken;
/**
* The end of line string for this machine.
*/
protected static final String eol = System.getProperty("line.separator", "\n");
/**
* Each entry in this array is an array of integers. Each array
* of integers represents a sequence of tokens (by their ordinal
* values) that is expected at this point of the parse.
*/
public int[][] expectedTokenSequences;
/**
* This is a reference to the "tokenImage" array of the generated
* parser within which the parse error occurred. This array is
* defined in the generated ...Constants interface.
*/
public String[] tokenImage;
/**
* This method has the standard behavior when this object has been
* created using the standard constructors. Otherwise, it uses
* "currentToken" and "expectedTokenSequences" to generate a parse
* error message and returns it. If this object has been created
* due to a parse error, and you do not catch it (it gets thrown
* from the parser), then this method is called during the printing
* of the final stack trace, and hence the correct error message
* gets displayed.
*/
public String getMessage() {
if (!specialConstructor) {
return super.getMessage();
}
String expected = "";
int maxSize = 0;
for (int i = 0; i < expectedTokenSequences.length; i++) {
if (maxSize < expectedTokenSequences[i].length) {
maxSize = expectedTokenSequences[i].length;
}
for (int j = 0; j < expectedTokenSequences[i].length; j++) {
expected += tokenImage[expectedTokenSequences[i][j]] + " ";
}
if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
expected += "...";
}
expected += eol + " ";
}
String retval = "Encountered \"";
Token tok = currentToken.next;
for (int i = 0; i < maxSize; i++) {
if (i != 0) retval += " ";
if (tok.kind == 0) {
retval += tokenImage[0];
break;
}
retval += TokenMgrError.addEscapes(tok.image);
tok = tok.next;
}
if (expectedTokenSequences.length == 1) {
retval += "Was expecting:" + eol + " ";
} else {
retval += "Was expecting one of:" + eol + " ";
}
retval += expected;
return retval;
}
/**
* getErrorInfo() was added to the parser generated code to provide clean
* output instead of the standard format of Exception.toString(). It returns
* a short description of the error that occured as well as the position of
* next token as part of the string.
*/
public String getErrorInfo()
{
if (!specialConstructor) {
return super.getMessage();
}
String expected = "";
int maxSize = 0;
for (int i = 0; i < expectedTokenSequences.length; i++) {
if (maxSize < expectedTokenSequences[i].length) {
maxSize = expectedTokenSequences[i].length;
}
for (int j = 0; j < expectedTokenSequences[i].length; j++) {
expected += tokenImage[expectedTokenSequences[i][j]] + " ";
}
if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
expected += "...";
}
expected += eol + " ";
}
String retval = "Unexpected \"";
Token tok = currentToken.next;
for (int i = 0; i < maxSize; i++) {
if (i != 0) retval += " ";
if (tok.kind == 0) {
retval += tokenImage[0];
break;
}
retval += TokenMgrError.addEscapes(tok.image);
tok = tok.next;
}
return retval;
}
}
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