| 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.