net.mintern.primitive.comparators

Interface DoubleComparator

public interface DoubleComparator

A comparison function that imposes total ordering on double values.

This is a @FunctionalInterface even though it isn't declared as one, so that it can be used in Java 6+.

Method Summary

Modifier and Type	Method and Description
int	compare(double d1, double d2) Compares d1 and d2.

Method Detail

compare

int compare(double d1,
            double d2)

Compares d1 and d2. Returns a negative value to indicate that d1 < d2, 0 to indicate that d1 == d2, and a positive value to indicate that d1 > d2.

Implementations of this method must maintain the following invariants:

• s(compare(x, y)) == -s(compare(y, x))
• s(compare(x, y)) == s(compare(y, z)) → s(compare(x, y)) == s(compare(x, z)) (transitivity)
• compare(x, y) == 0 → s(compare(x, z)) == s(compare(y, z)) ∀ z

where s(x) is defined as follows:

• x < 0: -1
• x == 0: 0
• x > 0: 1

Important Note

A floating-point compare implementation must be careful to maintain total ordering, in particular when comparing -0.0, 0.0, @{code NaN}, Double.NEGATIVE_INFINITY, and Double.POSITIVE_INFINITY values. See Double.compareTo(Double) for a valid example.

Parameters:

d1 - the first double to compare

d2 - the second double to compare

Returns:

a negative value, 0, or a positive value to indicate that d1 is less than, equal to, or greater than d2, respectively