compare
int compare(java.lang.Object first,
java.lang.Object second)
Compares its two arguments for order. Returns a negative integer, zero, or a positive integer
as the first argument is less than, equal to, or greater than the second. In the foregoing
description, the notation sgn(expression) designates the mathematical signum function, which is
defined to return one of -1, 0, or 1 according to whether the value of expression is negative,
zero or positive. The implementor must ensure that sgn(compare(x, y)) == -sgn(compare(y, x))
for all x and y. (This implies that compare(x, y) must throw an exception if and only if
compare(y, x) throws an exception.) The implementor must also ensure that the relation is
transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0. Finally, the
implementor must ensure that compare(x, y)==0 implies that sgn(compare(x, z))==sgn(compare(y,
z)) for all z. It is generally the case, but not strictly required that (compare(x, y)==0) ==
(x.equals(y)). Generally speaking, any comparator that violates this condition should clearly
indicate this fact. Note: this comparator imposes orderings that are inconsistent with equals.
- Parameters:
first - second - - Returns: