#4 add chain of responsibility pattern example - leave request - into project

Author: ThanhPhiNgo

README.md

@@ -82,4 +82,7 @@ Reference: https://gpcoder.com/4644-huong-dan-java-design-pattern-proxy/
 
 Reference: https://gpcoder.com/4665-huong-dan-java-design-pattern-chain-of-responsibility/
 
-> Review: Suitable for create and push Alert through applications (tools) by level
+> Review:
+>
+> -   Suitable for create and push Alert through applications (tools) by level
+> -   Summary: Execute an action by level chain, which has corresponding condition for each level

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Approver.java

@@ -0,0 +1,28 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public abstract class Approver {
+
+	protected Approver nextApprover;
+
+	public void approveLeave(LeaveRequest request) {
+		System.out.println("Checking permission for " + this.getClass().getSimpleName());
+
+		if (this.canApprove(request.getDays())) {
+			this.doApproving(request);
+		} else if (nextApprover != null) {
+			nextApprover.approveLeave(request);
+		}
+	}
+
+	public void setNext(Approver approver) {
+		this.nextApprover = approver;
+	}
+
+	protected void doApproving(LeaveRequest request) {
+		System.out.println("Leave request approved for " + request.getDays() + " days by " + getTitle());
+	}
+
+	protected abstract String getTitle();
+
+	protected abstract boolean canApprove(int numberOfDays);
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/ApproverPermission.java

@@ -0,0 +1,18 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public enum ApproverPermission {
+
+	Supervisor(3),
+	DeliveryManage(5),
+	Director(Integer.MAX_VALUE);
+
+	private int days;
+
+	private ApproverPermission(int days) {
+		this.days = days;
+	}
+
+	public int getDays() {
+		return this.days;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Client.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Client {
+
+	public static void main(String[] args) {
+
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(8));
+		System.out.println("---");
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(2));
+		System.out.println("---");
+		LeaveRequestWorkFlow.getApprover().approveLeave(new LeaveRequest(5));
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/DeliveryManage.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class DeliveryManage extends Approver {
+
+	@Override
+	protected String getTitle() {
+		return "Delivery Manager";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays <= ApproverPermission.DeliveryManage.getDays();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Director.java

@@ -0,0 +1,13 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Director extends Approver {
+	@Override
+	protected String getTitle() {
+		return "Director";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays > ApproverPermission.DeliveryManage.getDays();
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/LeaveRequest.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class LeaveRequest {
+
+	private int days;
+
+	public LeaveRequest(int days) {
+		this.days = days;
+	}
+
+	public int getDays() {
+		return this.days;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/LeaveRequestWorkFlow.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class LeaveRequestWorkFlow {
+
+	public static Approver getApprover() {
+		Approver supervisor = new Supervisor();
+		Approver manager = new DeliveryManage();
+		Approver director = new Director();
+
+		supervisor.setNext(manager);
+		manager.setNext(director);
+		return supervisor;
+	}
+}

design-pattern/src/main/java/com/phint2/pattern/behavioral/cor/leaverequest/Supervisor.java

@@ -0,0 +1,14 @@
+package com.phint2.pattern.behavioral.cor.leaverequest;
+
+public class Supervisor extends Approver {
+
+	@Override
+	protected String getTitle() {
+		return "Supervisor";
+	}
+
+	@Override
+	protected boolean canApprove(int numberOfDays) {
+		return numberOfDays <= ApproverPermission.Supervisor.getDays();
+	}
+}