public class CommissionEmployee extends Object {
    private final String firstName;
    private final String lastName;
    private final String socialSecurityNumber;
    private double grossSales; // gross weekly sales
    private double commissionRate; // commission percentage
}



public CommissionEmployee(String firstName, String lastName,
                          String socialSecurityNumber, double grossSales,
                          double commissionRate) {
                            
    if (grossSales < 0.0) {
        throw new IllegalArgumentException("Gross sales must be >= 0.0");
    }

    if (commissionRate <= 0.0 || commissionRate >= 1.0) {
        throw new IllegalArgumentException(
            "Commission rate must be > 0.0 and < 1.0");
    }

    this.firstName = firstName;
    this.lastName = lastName;
    this.socialSecurityNumber = socialSecurityNumber;
    this.grossSales = grossSales;
    this.commissionRate = commissionRate;
}

// return first name
public String getFirstName() { return firstName; }

// return last name
public String getLastName() { return lastName; }

// return social security number
public String getSocialSecurityNumber() { return socialSecurityNumber; }

// set gross sales amount
public void setGrossSales(double grossSales) {
    if (grossSales < 0.0) {
        throw new IllegalArgumentException("Gross sales must be >= 0.0");
    }
    this.grossSales = grossSales;
}

// return gross sales amount
public double getGrossSales() { return grossSales; }

// set commission rate
public void setCommissionRate(double commissionRate) {
    if (commissionRate <= 0.0 || commissionRate >= 1.0) {
        throw new IllegalArgumentException(
            "Commission rate must be > 0.0 and < 1.0");
    }
    this.commissionRate = commissionRate;
}

// return commission rate
public double getCommissionRate() { return commissionRate; }




// calculate earnings
public double earnings() { return commissionRate * grossSales; }

// return String representation of CommissionEmployee object
@Override // indicates that this method overrides a superclass method
public String toString() {
    return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f",
        "commission employee", firstName, lastName,
        "social security number", socialSecurityNumber,
        "gross sales", grossSales,
        "commission rate", commissionRate);
}