Lab Assignment: Extending the Leave Approval Program

You have been given a leave approval program that uses the Chain of Responsibility pattern to

handle leave requests.

Demo $-$ Chain or Responsibility Design Pattern

Your task is to extend the program by adding the following functionality:

Requirements:

Implement a new handler called CEO that represents the Chief Executive Officer in the

leave approval process. The CEO can approve any leave request less than $30$ days. if over

$30$ days $-$ reject leave request.

Update the Main class to include the new CEO handler in the chain of responsibility.

Modify each approver to have the system output a message that the leave request needs to

be moved to the next requester in the event the leave request exceeds the amount of leave

the approver is authorized to approve

Test your implementation by creating leave requests with various durations and verifying

that each request is approved by the appropriate handler in the chain.

Note:

You can assume that the existing classes $($LeaveApprover$,$ TeamLead,

DepartmentManager, $,$ LeaveRequest, and Main$)$ are already implemented

correctly.

You can use the existing code provided in the previous example as a starting point for your

implementation.

Chain of responsibility pattern:

Interface:

package ChainOfResponsibiltyDemo;

interface LeaveApprover $\{$

void setNextApprover$($LeaveApprover nextApprover$)$;

void approveLeave$($LeaveRequest leaveRequest$)$;

$\}$

Classes:

package ChainOfResponsibiltyDemo;

$//$ LeaveRequest class

class LeaveRequest $\{$

private int days;

public LeaveRequest$($int days$)\{$

this.days $=$ days;

$\}$

public int getDays$()\{$

return days;

$\}$

$\}$

package ChainOfResponsibiltyDemo;

class TeamLead implements LeaveApprover $\{$

private LeaveApprover nextApprover;

public void setNextApprover$($LeaveApprover nextApprover$)\{$

this.nextApprover $=$ nextApprover;

$\}$

public void approveLeave$($LeaveRequest leaveRequest$)\{$

if $($leaveRequest$.$getDays

System.out.println$("$Leave approved by Team Lead"$)$;

$\}$ else if $($nextApprover $!=$ null$)\{$

nextApprover.approveLeave$($leaveRequest$)$;

$\}$ else $\{$

System.out.println$("$Leave rejected"$)$;

$\}$

$\}$

$\}$

package ChainOfResponsibiltyDemo;

class DepartmentManager implements LeaveApprover $\{$

private LeaveApprover nextApprover;

public void setNextApprover$($LeaveApprover nextApprover$)\{$

this.nextApprover $=$ nextApprover;

$\}$

public void approveLeave$($LeaveRequest leaveRequest$)\{$

if $($leaveRequest$.$getDays

System.out.println$("$Leave approved by Department Manager"$)$;

$\}$ else if $($nextApprover $!=$ null$)\{$

nextApprover.approveLeave$($leaveRequest$)$;

$\}$ else $\{$

System.out.println$("$Leave rejected"$)$;

$\}$

$\}$

$\}$

package ChainOfResponsibiltyDemo;

class HRManager implements LeaveApprover $\{$

private LeaveApprover nextApprover;

public void setNextApprover$($LeaveApprover nextApprover$)\{$

this.nextApprover $=$ nextApprover;

$\}$

public void approveLeave$($LeaveRequest leaveRequest$)\{$

if $($leaveRequest$.$getDays

System.out.println$("$Leave approved by HR Manager"$)$;

$\}$ else if $($nextApprover $!=$ null$)\{$

nextApprover.approveLeave$($leaveRequest$)$;

$\}$ else $\{$

System.out.println$("$Leave rejected"$)$;

$\}$

$\}$

$\}$

Driver

package ChainOfResponsibiltyDemo;

public class CoRDriver $\{$

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

LeaveApprover teamLead $=$ new TeamLead$()$;

LeaveApprover departmentManager $=$ new DepartmentManager$()$;

LeaveApprover hrManager $=$ new HRManager$()$;

$//$ Set up the chain of responsibility

teamLead.setNextApprover$($departmentManager$)$;

departmentManager.setNextApprover$($hrManager$)$;

$//$ Create a leave request $-$ test with $4,14$ and $20$ to see the resu

LeaveRequest leaveRequest $=$ new LeaveRequest$(8)$;

$//$ Send the leave request for approval

teamLead.approveLeave$($leaveRequest$)$;

$\}$

$\}$