feat(oop): setting up

Author: PunGrumpy

Design-Patterns-in-OOP/04-lab/Customer.java

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+public abstract class Customer { //make this class abstract
+    public abstract String createMail(); //make this method abstract
+}

Design-Patterns-in-OOP/04-lab/CustomerMailApplication.java

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+import java.util.Scanner;
+public class CustomerMailApplication {
+    /**
+     * @param args the command line arguments
+     */
+    private Customer customer;
+    public CustomerMailApplication(Customer customer) {
+        this.customer = customer;
+    }
+    public static String getCustomerTypeFromUser() {
+        String customerType = null;
+        Scanner inp = new Scanner(System.in);
+        System.out.print("Please choose customer type 1. Regular, 2. Mountain, 3. Delinquent ");
+        int type = inp.nextInt();
+        switch(type) {
+            case 1:
+                customerType = "Regular";
+                break;
+            case 2:
+                customerType = "Mountain";
+                break;
+            case 3:
+                customerType = "Delinquent";
+                break;
+        }
+        inp.close();
+        return customerType;
+    }
+    public String generateMail() {
+        return customer.createMail();
+    }
+    
+    public static void main(String[] args) {
+        String customerType = getCustomerTypeFromUser();
+        Customer customer  = null;
+        switch(customerType) {
+            case "Regular":
+                customer = new RegularCustomer();
+                break;
+            case "Mountain":
+                customer = new MountainCustomer();
+                break;
+            case "Delinquent":
+                customer = new DelinquentCustomer();
+                break; 
+        }
+        CustomerMailApplication app = new CustomerMailApplication(customer);
+        System.out.println(app.generateMail());        
+    }
+}

Design-Patterns-in-OOP/04-lab/DelinquentCustomer.java

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+//make this class a subclass of customer
+public class DelinquentCustomer extends Customer {
+    @Override
+    public String createMail() {
+        return "Delinquent Customer";
+    }   
+}

Design-Patterns-in-OOP/04-lab/MountainCustomer.java

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+//make this class a subclass of customer
+public class MountainCustomer extends Customer {
+    @Override
+    public String createMail() {
+        return "Mountain Customer";
+    }
+}

Design-Patterns-in-OOP/04-lab/RegularCustomer.java

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+//make this class a subclass of customer
+public class RegularCustomer extends Customer {
+    @Override
+    public String createMail() {
+        return "Regular Customer";
+    }
+    
+}