| Return type | Name and parameters | 
|---|---|
| boolean | isNonnegative()Returns true if this period is zero or positive. | 
| boolean | isNonpositive()Returns true if this period is zero or negative. | 
| boolean | isPositive()Returns true if this period is positive, excluding zero. | 
Returns true if this period is zero or positive.
Returns true if this period is zero or negative.
Returns true if this period is positive, excluding zero.