/** The difference between 2 durations. Order is unimportant. */
@MethodContract(
pre = {@Expression("d1 != null"), @Expression("d2 != null")},
post = {
@Expression("result != null"),
@Expression("result.asMillisecond() == Math.abs(d1.asMillisecond() - d2.asMillisecond())")
})
public static Duration delta(Duration d1, Duration d2) {
assert preArgumentNotNull(d1, "d1");
assert preArgumentNotNull(d2, "d2");
long result = Math.abs(d1.asMillisecond() - d2.asMillisecond());
return new Duration(result, MILLISECOND);
}
/** The sum of the durations in {@code d}. */
@MethodContract(
pre = {
@Expression("for (int i = 0 .. d.length) {d[i] != null}"),
@Expression("sum (Duration aD : d) {d.asMillisecond()} <= Long.MAX_VALUE")
},
post = {
@Expression("result != null"),
@Expression("d.length == 0 ? result.asMillisecond() == 0"),
@Expression(
"d.length != 0 ? result.asMillisecond() == sum(d[1..d.length]) + d[0].asMillisecond()")
})
public static Duration sum(Duration... d) {
preSum(d);
long result = 0;
for (Duration aD : d) {
result += aD.asMillisecond();
}
return new Duration(result, MILLISECOND);
}