In PlayN, is there a cross-platform method for formatting decimals?

Question

How can I format a decimal value (e.g. 1.29854) so that it produces a string rounded to 2 decimal places (1.30)?

I'm lost because GWT doesn't support the native Java number formatting classes and I can't find any PlayN support for number formatting.

I've confirmed that, while the following works in the Java version, the HTML version fails to compile:

    DecimalFormat df = new DecimalFormat("0.00");
    String formattedValue = df.format(1.29854);

Answer 1

This mostly worked for my case (for one-digit numbers between 0 and 10):

        String formatted = ((Double) (Math.round(doubleValue * 100.0) / 100.0)).toString();
        formatted = (formatted + "00").substring(0,4);

Verified in Java and HTML versions. Here's a unit test:

@Test
public void testNumberFormatting() {
    ArrayList<Double> testCases = Lists.newArrayList(
        0.0, 0.986, 1.0, 1.2, 1.29, 1.295);
    ArrayList<String> expectResults = Lists.newArrayList(
        "0.00", "0.99", "1.00", "1.20", "1.29", "1.30");

    for (int n=0; n<testCases.size(); n++) {
        Double testCase = testCases.get(n);
        String formatted = ((Double) (Math.round(testCase * 100.0) / 100.0)).toString();
        formatted = (formatted + "00").substring(0,4);
        assertEquals(expectResults.get(n), formatted);
        System.out.println(formatted);
    }
}