Fastest most efficient way to determine decimal value is integer in Java

Question

Given a double variable named sizeValue and sizeValue contains something other than 0, what is the most efficient way to determine that sizeValue contains a value that is an integer?

Currently i'm using

sizeValue % 1 == 0

any other faster ways?

Answer 1

give a try to Math.ceil:

private static boolean isInt(double x) {
     return x == Math.ceil(x);
}

EDIT

I've done some benchmarks with the following methods:

private static boolean isInt1(double x) {
    return x == (int) x;
}

private static boolean isInt2(double x) {
    return x == Math.ceil(x);
}

private static boolean isInt3(double x) {
    return x % 1 == 0;
} 

isInt1 is the faster of them (on a sunjre 1.6)