/*
* Copyright 2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* $Header:$
*/
package org.apache.beehive.netui.script.el.parser;
import org.apache.beehive.netui.util.internal.InternalStringBuilder;
/**
* 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.
* <p/>
* You can modify this class to customize your error reporting
* mechanisms so long as you retain the public fields.
*/
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;
}
/**
* 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;
/**
* 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 += add_escapes(tok.image);
tok = tok.next;
}
retval += "\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn;
retval += "." + eol;
if(expectedTokenSequences.length == 1) {
retval += "Was expecting:" + eol + " ";
} else {
retval += "Was expecting one of:" + eol + " ";
}
retval += expected;
return retval;
}
/**
* The end of line string for this machine.
*/
protected String eol = System.getProperty("line.separator", "\n");
/**
* Used to convert raw characters to their escaped version
* when these raw version cannot be used as part of an ASCII
* string literal.
*/
protected String add_escapes(String str) {
InternalStringBuilder retval = new InternalStringBuilder();
char ch;
for(int i = 0; i < str.length(); i++) {
switch(str.charAt(i)) {
case 0:
continue;
case '\b':
retval.append("\\b");
continue;
case '\t':
retval.append("\\t");
continue;
case '\n':
retval.append("\\n");
continue;
case '\f':
retval.append("\\f");
continue;
case '\r':
retval.append("\\r");
continue;
case '\"':
retval.append("\\\"");
continue;
case '\'':
retval.append("\\\'");
continue;
case '\\':
retval.append("\\\\");
continue;
default:
if((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
String s = "0000" + Integer.toString(ch, 16);
retval.append("\\u" + s.substring(s.length() - 4, s.length()));
} else {
retval.append(ch);
}
continue;
}
}
return retval.toString();
}
}