Limiting Number of Decimal Places in GWT?

Check out NumberFormat (com.google.gwt.i18n.client.NumberFormat) in the GWT Javadoc.

I've never used it but I see this example in there:

// Custom format
value = 12345.6789;
formatted = NumberFormat.getFormat("000000.000000").format(value);
// prints 012345.678900 in the default locale
GWT.log("Formatted string is" + formatted);

So this should work for you.

Update

This method provides the same functionality as the one in your question. I went ahead and asked for the most efficient way to go about this, see that question here. (Sorry this answer has been edited so much - it was just bugging me)

public static String getFormatted(double value, int decimalCount) {
    StringBuilder numberPattern = new StringBuilder(
            (decimalCount <= 0) ? "" : ".");
    for (int i = 0; i < decimalCount; i++) {
        numberPattern.append('0');
    }
    return NumberFormat.getFormat(numberPattern.toString()).format(value);
}

Alternatives include using a set amount of "0"'s and using substring to pull out the required pattern as @Thomas Broyer mentioned in the comments.

You can use

NumberFormat decimalFormat = NumberFormat.getFormat(".##");

from GWT library which will render for example 1234.789789 to 1234.78

You can find a full working example here: http://gwt.google.com/samples/Showcase/Showcase.html#!CwNumberFormat