Java™ How To Program (Early Objects), Tenth Edition

9.4.5 CommissionEmployee–BasePlusCommissionEmployee Inheritance Hierarchy Using private Instance Variables

Let’s reexamine our hierarchy once more, this time using good software engineering practices.

Class CommissionEmployee

Class CommissionEmployee (Fig. 9.10) declares instance variables firstName, lastName, socialSecurityNumber, grossSales and commissionRate as private (lines 6–10) and provides public methods getFirstName, getLastName, getSocialSecurityNumber, setGrossSales, getGrossSales, setCommissionRate, getCommissionRate, earnings and toString for manipulating these values. Methods earnings (lines 87–90) and toString (lines 93–101) use the class’s get methods to obtain the values of its instance variables. If we decide to change the ...