Java String Quote QuoteValueIfNeeded(String str)

Description

Quote Value If Needed

License

Creative Commons License

Declaration

public static String QuoteValueIfNeeded(String str) 

Method Source Code

//package com.java2s;

public class Main {
    public static String QuoteValueIfNeeded(String str) {
        return (!ShouldQuote(str)) ? str : QuoteValue(str);
    }//  w ww .j a  v  a  2 s  . c om

    private static boolean ShouldQuote(String str) {
        if (str.length() == 0) {
            // Empty String
            return true;
        }
        if (str.charAt(str.length() - 1) == ' ' || str.charAt(str.length() - 1) == '\t') {
            // Space or tab at end
            return true;
        }
        if (str.charAt(0) == ' ' || str.charAt(0) == '\t') {
            // Space or tab at beginning
            return true;
        }
        for (int i = 0; i < str.length(); ++i) {
            if (str.charAt(i) == '\\' || str.charAt(i) == '"') {
                return true;
            }
            if ((str.charAt(i) == ' ' || str.charAt(i) == '\t') && i + 1 < str.length()
                    && (str.charAt(i + 1) == ' ' || str.charAt(i + 1) == '\t')) {
                // run of two or more space and/or tab
                return true;
            }
            if ((str.charAt(i) == '\r') && i + 1 < str.length() && (str.charAt(i + 1) == '\n')) {
                // CRLF
                if (i == 0 && i + 2 < str.length() && (str.charAt(i + 1) == ' ' || str.charAt(i + 1) == '\t')) {
                    // CRLF followed by space or tab at beginning
                    return true;
                }
                continue;
            }
            char c = str.charAt(i);
            // Has specials, or CTLs other than tab
            if ((c < 0x20 && c != '\t') || c == 0x7F || c == 0x28 || c == 0x29 || c == 0x3c || c == 0x3e
                    || c == 0x5b || c == 0x5d || c == 0x3a || c == 0x3b || c == 0x40 || c == 0x5c || c == 0x2c
                    || c == 0x2e || c == '"') {
                return true;
            }
        }
        return false;
    }

    /**
     * Quotes a string according to RFC 5322 rules.
     * @param str A string object.
     * @return A string object.
     */
    public static String QuoteValue(String str) {
        StringBuilder builder = new StringBuilder();
        builder.append('"');
        for (int i = 0; i < str.length(); ++i) {
            if (str.charAt(i) == '\\' || str.charAt(i) == '"') {
                builder.append('\\');
                builder.append(str.charAt(i));
            } else {
                builder.append(str.charAt(i));
            }
        }
        builder.append('"');
        return builder.toString();
    }
}

Related

1. quoteText(String textToQuote, boolean sbAppend)
2. quoteTo(CharSequence cs, StringBuilder target)
3. quoteTokenize(String clientResponse)
4. QuoteValue(String str)
5. quoteValue(String value)
6. quoteValues(String value)
7. quoteWhitespaces(String path)
8. quoteWrap(String name)