Tag Library for Date submission

[Jes Sie]

Dear people,
Does anybody know where can I obtain a Struts Tag Library or a similar example to feature input of Date, Mth and Year values via the HTML/JSP screens?
The String values submitted would then be converted to java.util.Calendar or GregorianCalendar ...hopefully something like 'GregorianCalendar(int year, int month, int date)' ?
FYI, the timezone and time could be just current system defaults.
Thanks. Any help would be much appreciated.

[Adam Hardy]

Hi again Simon,
it's generally held to be best practice to use a string property for all types, not just dates.
In your formbean, you would then convert your original type variable into a string using the locale or fixed US locale or whatever you choose, and then in the formbean.validate() you would convert the user's date string back to date type using your own code.
I've been using this code, but I haven't released it yet, so it's not been tested thoroughly:

 
 /**
     * Gets the default date format pattern to show to users
     *
     * @return a string containing the pattern the user must use to enter dates
     */
    public static String getDatePattern(
        Locale pLocale)
    {
        if (Locale.GERMAN == pLocale || Locale.GERMANY == pLocale)
            return "dd.mm.yyyy";
        else
            return "yyyy-mm-dd";
    }
    /**
     * Parse a string containing date info in local format
     * @param pDateString user's localized date
     * @param pLocale     user's locale
     *
     * @return the correct parsed date object, or null
     */
    public static Date parseDateString(
        String pDateString,
        Locale pLocale)
    {
        return parseDateString(pDateString,getDatePattern(pLocale));
    }
    /**
     * String to java.util.Date
     * @param pDateString  the string in the format required
     * @param pDatePattern the parse pattern that defines the format as
     *                     per java.text.SimpleDateFormat e.g. dd.MM.yyyy
     *
     * @return if it's a crap date, null is returned
     */
    public static Date parseDateString(
        String pDateString,
        String pDatePattern)
    {
        Date lDate = new Date();
        synchronized (lDate)
        {
            if (pDateString != null)
            {
                try
                {
                    SimpleDateFormat lFormat = new SimpleDateFormat(pDatePattern);
                    ParsePosition lParse = new ParsePosition(0);
                    lDate = lFormat.parse(pDateString, lParse);
                    GregorianCalendar lCalendar = new GregorianCalendar();
                    lCalendar.setTime(lDate);
                    switch (lCalendar.get(Calendar.MONTH))
                    {
                    case Calendar.JANUARY:
                    case Calendar.MARCH:
                    case Calendar.MAY:
                    case Calendar.JULY:
                    case Calendar.AUGUST:
                    case Calendar.OCTOBER:
                    case Calendar.DECEMBER:
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) < 1)
                            lDate = null;
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) > 31)
                            lDate = null;
                        break;
                    case Calendar.APRIL:
                    case Calendar.JUNE:
                    case Calendar.SEPTEMBER:
                    case Calendar.NOVEMBER:
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) < 1)
                            lDate = null;
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) > 30)
                            lDate = null;
                        break;
                    case Calendar.FEBRUARY:
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) < 1)
                            lDate = null;
                        if (lCalendar.get(Calendar.DAY_OF_MONTH) > lCalendar.getActualMaximum(Calendar.DAY_OF_MONTH))
                            lDate = null;
                        break;
                    }
                }
                catch (Exception e)
                {
                    lDate = null;
                }
            }
            else
            {
                lDate = null;
            }
        }
        return lDate;
    }