Question

I have following method:

public static String formatDate(Date date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    Calendar today = Calendar.getInstance();
    Calendar yesterday = Calendar.getInstance();
    yesterday.add(Calendar.DATE, -1);
    DateFormat timeFormatter = new SimpleDateFormat("hh:mma");
    DateFormat dateTimeFormatter = new SimpleDateFormat("MMM d, yyyy - hh:mma");

    if (calendar.get(Calendar.YEAR) == today.get(Calendar.YEAR) && calendar.get(Calendar.DAY_OF_YEAR) == today.get(Calendar.DAY_OF_YEAR) && calendar.get(Calendar.HOUR_OF_DAY) == today.get(Calendar.HOUR_OF_DAY) && calendar.get(Calendar.MINUTE) == today.get(Calendar.MINUTE)) {
        return "few seconds ago ";
    } else if (calendar.get(Calendar.YEAR) == today.get(Calendar.YEAR) && calendar.get(Calendar.DAY_OF_YEAR) == today.get(Calendar.DAY_OF_YEAR) && calendar.get(Calendar.HOUR_OF_DAY) == today.get(Calendar.HOUR_OF_DAY)) {
        return "few minutes ago ";
    } else if (calendar.get(Calendar.YEAR) == today.get(Calendar.YEAR) && calendar.get(Calendar.DAY_OF_YEAR) == today.get(Calendar.DAY_OF_YEAR)) {
        return "today " + timeFormatter.format(date);
    } else if (calendar.get(Calendar.YEAR) == yesterday.get(Calendar.YEAR) && calendar.get(Calendar.DAY_OF_YEAR) == yesterday.get(Calendar.DAY_OF_YEAR)) {
        return "yesterday " + timeFormatter.format(date);
    } else {
        return dateTimeFormatter.format(date);
    }
}

How do I write this in client side GWT?

Answer 1

There are four ways to do this that occur to me:

1. Don’t do it on the client side, but on the server side.
   Calendar is not emulated in GWT on the client side.
2. If you must do this on the client side, try using the deprecated methods
   in the Date class. They still work, and they’ve all been deprecated
   in favour of methods in Calendar, so you’d just be rolling back the
   clock a bit.
3. Speaking about rolling back the clock, you could
   also just roll forward, as it were. Calendar emulation is coming to
   GWT, at least that’s what I’ve read. You could do (1) for now, then
   move that method to the client when Calendar arrives. Alternately,
   you could do (2) for now, and swap it for your original
   Calendar-based code when Calendar arrives.
4. Use the getTime() method on Date (which is not deprecated and is emulated by GWT on the client side) and do straight-up integer comparisons to determine what string to return. getTime() returns milliseconds, so “a few seconds ago” would be a difference of 60,000 milliseconds or less, “a few minutes ago” would be a difference of 3,600,000 milliseconds or less, and so on.

Go for 4.

Use the methods in com.google.gwt.i18n.client.DateTimeFormat to do your date/time formatting.