Refactoring is 'the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure,$\text{'}$ according to Martin Fowler, the 'father' of refactoring.The subtitle of Martin Fowler$$s seminal book, Refactoring, is $$Improving the Design of Existing Code.$$ That$$s pretty much the definition of refactoring.

There are several elementary sorting algorithms, details of which can be found in books on algorithms, Knuth: The Art of Computer Programming, vol. $3,3$rd ed$.$ is an encyclopedic reference. Elementary algorithms are more than good enough for sorting reasonably large arrays. What is "reasonably large"? The answer, as it often is$,$ is $"$It depends" $-$ on the kind of element sorted, the kind of computer used, and on how fast "pretty fast" is$.$

$2$ points Modification $1$: Payable Interface

Modify the Firm program such that it expands its use of polymorphism by creating an interface called Payable $($filename Payable.java$).$ You will move the abstract pay method from StaffMember into Payable.

Reminder: Don't forget to have StaffMember implement the interface.

$2$ points Modification $2$: VacationTime Interface

Modify the Firm program such that all employees can be given different vacation options depending on their classification. Create an interface called VacationTime $($filename VacationTime.java$)$ containing one abstract method called vacation that returns the number of vacation days a person has $($return an int$).$

Give all employees a standard number of vacation days $(14)$ by initializing a final$/$constant STANDARD$\_$VACATION $=14$ inside VacationTime.

Then override the vacation method in ALL the classes derived from StaffMember as follows:

Volunteer $($who are not Employees$)$: $0$

Employee: STANDARD$\_$VACATION $($vacation example for Employee: return STANDARD$\_$VACATION$)$

Hourly: STANDARD$\_$VACATION $-7$

Executive: STANDARD$\_$VACATION $+$ extraVacation

NOTE: You will need to add extraVacation as instance variable to Executive and pass it in as an argument to the constructor.

Reminder: Don't forget to have StaffMember implement the interface.

Call vacation method inside the loop already used by payday method so we see each StaffMember's vacation days.

AFTER you get the above working, continue on to$...$

$2$ points Modification $3$: Update Sorting class

Update the Sorting class so that both sorting algorithms put the values in descending order.

THIS IS ONLY CHANGE TO Sorting.java NEEDED.

$2$ points Modification $4$: Update StaffMember

Update the StaffMember class as it now needs to OVERRIDE compareTo method $($we will use names for comparing$).$ This means StaffMember needs to implement the Comparable interface so the Sorting.java methods work.

HINT: add a getName $($returns a String$)$ method to StaffMember to be used in the compareTo method

$2$ points Modification $5$: Update main$()$

We sort the array of StaffMembers based on name field using the updated selection OR insertion sort from Sorting.java. Define a sort method in the class that has direct access to the array $-$ in our program it is main$()$

Call the sort method in main before calling payday. Here is what main$()$ should look like eventually:

public class Firm

$\{$

$//-------------------------------------------------------$

$//$ Creates a staff of employees for a firm and pays them.

$//-------------------------------------------------------$

public static void main$($String$[]$ args$)$

$\{$

Staff personnel $=$ new Staff$()$;

personnel.sort$()$; $//$call sort method before payday

personnel.payday$()$;

$\}$

$\}$Sample Output

Name: Woody

Address: $789$ Off Rocker

Phone: $555-0000$

Social Security Number: $010-20-3040$

Paid: $1169\mathrm{.}23$

Vacation days available: $14$

$-----------------------------------$

Name: Sam

Address: $123$ Main Line

Phone: $555-0469$

Social Security Number: $123-45-6789$

Paid: $2923\mathrm{.}07$

Vacation days available: $26$

$-----------------------------------$

Name: Norm

Address: $987$ Suds Blvd$.$

Phone: $555-8374$

Thanks!

Vacation days available: $0$

$-----------------------------------$

Name: Diane

Address: $678$ Fifth Ave.

Phone: $555-0690$

Social Security Number: $958-47-3625$

Current hours: $40$

Paid: $422\mathrm{.}0$

Vacation days available: $7$

$-----------------------------------$

Name: Cliff

Address: $321$ Duds Lane

Phone: $555-7282$

Thanks!

Vacation days available: $0$

$-----------------------------------$

Name: Carla

Address: $456$ Off Line

Phone: $555-0101$

Social Security Number: $987-65-4321$

Paid: $1246\mathrm{.}15$

Vacation days available: $14$

$-----------------------------------$