encoder.java

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            return null;
        }
        StringBuffer ret = new StringBuffer();

        // URLEncode the text string. This produces a very similar encoding to JavaSscript
        // encoding, except the blank which is not encoded into a %20.
        String enc = encode(source, encoding, true);
        for(int z = 0;z < enc.length();z++) {
            if(enc.charAt(z) == '+') {
                ret.append("%20");
            }
            else {
                ret.append(enc.charAt(z));
            }
        }
        return ret.toString();
    }

    /**
     * Escapes a String so it may be printed as text content or attribute
     * value in a HTML page or an XML file.<p>
     * 
     * This method replaces the following characters in a String:
     * <ul>
     * <li><b>&lt;</b> with &amp;lt;
     * <li><b>&gt;</b> with &amp;gt;
     * <li><b>&amp;</b> with &amp;amp;
     * <li><b>&quot;</b> with &amp;quot;
     * </ul>
     * 
     * @param source the string to escape
     * @return the escaped string
     * 
     * @see #escapeHtml(String)
     */
    public static String escapeXml(String source) {
        if (source == null) return null;
        StringBuffer result = new StringBuffer(source.length()*2);
        int terminatorIndex;
        for(int i = 0;i < source.length(); ++i) {
            char ch = source.charAt(i);
            switch (ch) {
                case '<' :
                    result.append("&lt;");
                    break;
                case '>' :
                    result.append("&gt;");
                    break;
                case '&' :
                    // Don't escape already escaped international and special characters
                    if ((terminatorIndex = source.indexOf(";",i)) > 0)
                        if(source.substring(i + 1, terminatorIndex).matches("#[0-9]+"))
                            result.append(ch);
                        else 
                            result.append("&amp;");
                    else
                        result.append("&amp;");
                    break;
                case '"' :
                    result.append("&quot;");
                    break;
                default :
                    result.append(ch);
            }
        }
        return new String(result);
    }   

    /**
     * Escapes special characters in a HTML-String with their number-based 
     * entity representation, for example &amp; becomes &amp;#38;.<p>
     * 
     * A character <code>num</code> is replaced if<br>
     * <code>((ch !=  32) && ((ch > 122) || (ch < 48) || (ch == 60) || (ch == 62)))</code><p>
     * 
     * @param source the String to escape
     * @return String the escaped String
     * 
     * @see #escapeXml(String)
     */
    public static String escapeHtml(String source) {
        int terminatorIndex;
        if (source == null) return null;
        StringBuffer result = new StringBuffer(source.length()*2);
        for(int i = 0;i < source.length();i++) {
            int ch = source.charAt(i);
            // Avoid escaping already escaped characters;
            if((ch == 38) && ((terminatorIndex = source.indexOf(";",i)) > 0)) {
                if(source.substring(i + 1, terminatorIndex).matches("#[0-9]+|lt|gt|amp|quote")) {
                    result.append(source.substring(i, terminatorIndex + 1));
                    // Skip remaining chars up to (and including) ";"
                    i = terminatorIndex;
                    continue;
                }
            }
            if((ch !=  32) && ((ch > 122) || (ch < 48) || (ch == 60) || (ch == 62))) {
                result.append("&#");
                result.append(ch);
                result.append(";");
            }
            else {
                result.append((char)ch);
            }
        }
        return new String(result);
    }

    /**
     * Escapes non ASCII characters in a HTML-String with their number-based 
     * entity representation, for example &amp; becomes &amp;#38;.<p>
     * 
     * A character <code>num</code> is replaced if<br>
     * <code>(ch > 255)</code><p>
     * 
     * @param source the String to escape
     * @return String the escaped String
     * 
     * @see #escapeXml(String)
     */
    public static String escapeNonAscii(String source) {
        if (source == null) return null;
        StringBuffer result = new StringBuffer(source.length()*2);
        for(int i = 0;i < source.length();i++) {
            int ch = source.charAt(i);
            if(ch > 255) {
                result.append("&#");
                result.append(ch);
                result.append(";");
            }
            else {
                result.append((char)ch);
            }
        }
        return new String(result);
    }
    
    /**
     * Decodes a String in a way that is compatible with the JavaScript 
     * unescape function.
     * 
     * @param Source The String to be decoded.
     * @return The JavaScript unescaped String.
     */
    public static String unescape(String source, String encoding) {
        if(source == null){
            return null;
        }
        int len = source.length();
        // to use standard decoder we need to replace '+' with "%20" (space)
        StringBuffer preparedSource = new StringBuffer(len);
        for (int i = 0; i < len; i++) {
            char c = source.charAt(i);
            if (c == '+') {
                preparedSource.append("%20");
            } else {
                preparedSource.append(c);
            }
        }
        return decode(preparedSource.toString(), encoding, true);
    }
    
    /**
     * Changes the encoding of a byte array that represents a String.<p>
     * 
     * @param input the byte array to convert
     * @param oldEncoding the current encoding of the byte array
     * @param newEncoding the new encoding of the byte array
     * @return byte[] the byte array encoded in the new encoding
     */
    public static byte[] changeEncoding(byte[] input, String oldEncoding, String newEncoding) {
        if ((oldEncoding == null) || (newEncoding == null)) return input;
        if (oldEncoding.trim().equalsIgnoreCase(newEncoding.trim())) return input;
        byte[] result = input;
        try {
            result = (new String(input, oldEncoding)).getBytes(newEncoding);
        } catch (UnsupportedEncodingException e) {
            // return value will be input value
        }
        return result;
    }
    
    /**
     * Re-decodes a String that has not been correctly decoded and thus has scrambled
     * character bytes.<p>
     * 
     * This is an equivalent to the JavaScript "decodeURIComponent" function.
     * It converts from the default "UTF-8" to the currently selected system encoding.<p>
     * 
     * @param input the String to convert
     * @return String the converted String
     */
    public static String redecodeUriComponent(String input) {
       if (input == null) return input;
       return new String(changeEncoding(input.getBytes(), C_URI_ENCODING, A_OpenCms.getDefaultEncoding())); 
    }
}