RELEASE_2_1_13/src/java/org/apache/cocoon/components/xpointer/parser/TokenMgrError.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package org.apache.cocoon.components.xpointer.parser;

/**
 * @version CVS $Id$
 *
 */
public class TokenMgrError extends Error {
    /*
     * Ordinals for various reasons why an Error of this type can be thrown.
     */

    /**
     * Lexical error occured.
     */
    static final int LEXICAL_ERROR = 0;

    /**
     * An attempt wass made to create a second instance of a static token manager.
     */
    static final int STATIC_LEXER_ERROR = 1;

    /**
     * Tried to change to an invalid lexical state.
     */
    static final int INVALID_LEXICAL_STATE = 2;

    /**
     * Detected (and bailed out of) an infinite loop in the token manager.
     */
    static final int LOOP_DETECTED = 3;

    /**
     * Indicates the reason why the exception is thrown. It will have
     * one of the above 4 values.
     */
    int errorCode;

    /**
     * Replaces unprintable characters by their espaced (or unicode escaped)
     * equivalents in the given string
     */
    protected static final String addEscapes(String str) {
        StringBuffer retval = new StringBuffer();
        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();
    }

    /**
     * Returns a detailed message for the Error when it is thrown by the
     * token manager to indicate a lexical error.
     * Parameters : 
     *    EOFSeen     : indicates if EOF caused the lexicl error
     *    curLexState : lexical state in which this error occured
     *    errorLine   : line number when the error occured
     *    errorColumn : column number when the error occured
     *    errorAfter  : prefix that was seen before this error occured
     *    curchar     : the offending character
     * Note: You can customize the lexical error message by modifying this method.
     */
    protected static String lexicalError(
        boolean EOFSeen,
        int lexState,
        int errorLine,
        int errorColumn,
        String errorAfter,
        char curChar) {
        return (
            "Lexical error at line "
                + errorLine
                + ", column "
                + errorColumn
                + ".  Encountered: "
                + (EOFSeen
                    ? "<EOF> "
                    : ("\"" + addEscapes(String.valueOf(curChar)) + "\"")
                        + " ("
                        + (int) curChar
                        + "), ")
                + "after : \""
                + addEscapes(errorAfter)
                + "\"");
    }

    /**
     * You can also modify the body of this method to customize your error messages.
     * For example, cases like LOOP_DETECTED and INVALID_LEXICAL_STATE are not
     * of end-users concern, so you can return something like : 
     *
     *     "Internal Error : Please file a bug report .... "
     *
     * from this method for such cases in the release version of your parser.
     */
    public String getMessage() {
        return super.getMessage();
    }

    /*
     * Constructors of various flavors follow.
     */

    public TokenMgrError() {
    }

    public TokenMgrError(String message, int reason) {
        super(message);
        errorCode = reason;
    }

    public TokenMgrError(
        boolean EOFSeen,
        int lexState,
        int errorLine,
        int errorColumn,
        String errorAfter,
        char curChar,
        int reason) {
        this(
            lexicalError(
                EOFSeen,
                lexState,
                errorLine,
                errorColumn,
                errorAfter,
                curChar),
            reason);
    }
}