Format date without year

Question

How can create text representation of some date, that takes locale into account and contains only day and month (no year)?

Following code gives me s

Answer 1

Although Andrzej Pronobis's answer is very good, it doesn't work for instance with ZH local. I ended up with manual removing year from localized pattern. This function was tested for all locals for SHORT, MEDIUM, LONG and FULL formats.

public String removeYearFromPattern(String pattern) throws IllegalArgumentException {
    int yPos = 0;
    while (yPos < pattern.length() && pattern.charAt(yPos) != 'y' && pattern.charAt(yPos) != 'Y') {
        if (pattern.charAt(yPos) == '\'') {
            yPos++;
            while (yPos < pattern.length() && pattern.charAt(yPos) != '\'') yPos++;
        }
        yPos++;
    }
    if (yPos >= pattern.length()) throw new IllegalArgumentException("Did not find year in pattern");
    String validPatternLetters = "EMd";
    // go forward
    int endPos = yPos;
    while (endPos < pattern.length() && validPatternLetters.indexOf(pattern.charAt(endPos)) == -1) {
        endPos++;
        if (endPos < pattern.length() && pattern.charAt(endPos) == '\'') {
            endPos++;
            while (endPos < pattern.length() && pattern.charAt(endPos) != '\'')
                endPos++;
        }
    }
    if (endPos != pattern.length()) validPatternLetters += ',';
    // go backward
    int startPos = yPos;
    while (startPos >= 0 && validPatternLetters.indexOf(pattern.charAt(startPos)) == -1) {
        startPos--;
        if (startPos >= 0 && pattern.charAt(startPos) == '\'') {
            startPos--;
            while (startPos >= 0 && pattern.charAt(startPos) != '\'') startPos--;
        }
    }
    startPos++;
    String yLetters = pattern.substring(startPos, endPos);
    return pattern.replace(yLetters, " ").trim();
}

Function above can be tested by running:

for (Locale locale : Locale.getAvailableLocales()) {
    SimpleDateFormat df = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.FULL, locale);
    String dfPattern = "?";
    String newPattern = "?";
    try {
        dfPattern = df.toPattern();
        newPattern = removeYearFromPattern(dfPattern);
        df.applyPattern(newPattern);
    } catch (IllegalArgumentException e) {
        Log.e(TAG, "Error removing year for " + locale + ": " + e.getMessage());
    }
    Log.d(TAG, locale + ": old  " + dfPattern + "; new " + newPattern + "; result " + df.format(new Date()));
}

I know it is not as elegant as regex, but it is a little bit faster and works for all locals (if I am able to recognize).