Company Bookkeeping

A company employs and pays $4$ types of employees $($each with its own job code$)$:

Hourly. Each hourly employee has an hourly wage and is paid weekly. If an employee works $40$ hours or less in a

week, then the employee$$s pay is the product of the number of hours worked and the hourly wage. If an employee

works more than $40$ hours in a week, then the employee is paid the hourly wage for the first $40$ hours of work and

$1\mathrm{.}5$ times the hourly rate for the hours worked in excess of $40.$ The code for this job type is $$HRLY$.$

Salaried. A salaried employee is paid the same amount each week. The code for this job type is $$SLRY$.$

Commission. The pay for employees that work on commission is a percentage of their weekly sales. The code for

this job type is $$COMM$.$

Limited Commission. A limited commission employee is paid similarly to a commission employee except that a

limited commission employee is guaranteed a minimum amount, his or her base pay, but commission pay is

limited to no more than twice the base pay. The code for this job is type $$LCOM$.$

The above pay descriptions do not include bonuses. Employees may also earn bonuses that are in addition to the pay the

earn as described above. Each week, any bonus that an employee has earned is added to the pay that is calculated by job

type.

The company also pays for utilities such as electricity, internet, telephone, and water. The amount of a utility bill is the

sum of two parts. The first part is calculated based on the usage of the utility by the company. This part is calculated as

the product of the amount of the utility used by the company for the week and the billing rate for the utility. The second

part is a base fee that is charged each week regardless of the amount of the utility that is used.

Programming the Bookkeeping

Create a Java program that handles some bookkeeping tasks for the company by defining the following interfaces and

classes. Your program must implement the UML class diagram that is at the end of this assignment description and as

described below.

$1.$ The PayableEntity interface requires its implementors to define an amountOwed method that takes no arguments

and returns a double value.

$2.$ The Employee abstract class implements the PayableEntity interface. It represents employees of all types. It has a

static numEmployees variable to count each Employee instance as it is created. It has non$-$static name and bonus

instance variables to represent an employee$$s name and bonus amount. The class has the following methods.

$$ A constructor that takes the employee$$s name as an argument and increments the employee count.

$$ An abstract calcPrebonusPay method for calculating an employee$$s without including any bonus.

$$ An abstract getJobCode method that returns a four$-$character string representing the employee$$s job type.

$$ A static getNumEmployees method that returns the number of Employee instances that have been created.

$$ A calcTotalPay method that calls the calcPrebonusPay method and adds the employee$$s bonus to the

result.

$$ An amountOwed method that returns the result of calling the calcTotalPay method.

$$ Two getters: getName and getBonus; and one setter: setBonus

$$ A toString method that returns a string containing the instance$$s name, job code, pre$-$bonus pay, and total pay

formatted as follows. A minimum of $15$ characters is dedicated to the employee$$s name which is left justified. This

is followed by a single space and then the employee$$s $4-$character job code. This is followed by a single space and

a dollar sign. After the dollar sign a minimum of $8$ characters is dedicated to the employee$$s pre$-$bonus pay which

includes a decimal point and two digits after the decimal point. Following that is a space, a dollar sign and then at

least $8$ characters for the employee$$s total pay including a decimal point and two following digits. Both pre$-$bonus

pay and total pay are right justified. $($See Figure $1).$ Use String.format to generate the string. Use only space

characters for spacing. Do not include leading or trailing whitespace $($space$,$ tab, new line, etc.$)$ in the string.

Figure $1.$ Example of the form of a string returned by the toString method of the Employee class

$3.$ The HourlyEmployee class is a subclass of the Employee class. It has instance variables for the hourly employee$$s

hourly wage and hours worked. In addition to having concrete definitions for calcPrebonusPay and getJobCode,

this class has the following methods.

$$ A constructor that takes the hourly employee$$s name and hourly wage as arguments. The constructor should call

the Employee constructor so that the hourly employee is counted.

$$ A setHoursWorked method that takes as its only argument the number of hours worked by the employee

$4.$ The SalariedEmployee class is a subclass of the Employee class. It has instance variables for the salaried

employee$$s weekly pay. In addition to having concrete definitions for the calcPrebonusPay and getJobCode, this

class has the following method.

$$ A