Strategy پترن در جاوا (Strategy Pattern)

public interface PaymentStrategy {



     public void pay(int amount);

}

public class PaypalStrategy implements PaymentStrategy {



     private String emailId;

     private String password;



     public PaypalStrategy(String email, String pwd) {

          this.emailId = email;

          this.password = pwd;

     }



     @Override

     public void pay(int amount) {

          System.out.println(amount + " paid using Paypal.");

     }



}

public class CreditCardStrategy implements PaymentStrategy {



     private String name;

     private String cardNumber;

     private String cvv;

     private String dateOfExpiry;



     public CreditCardStrategy(String nm, String ccNum, String cvv,

              String expiryDate) {

          this.name = nm;

          this.cardNumber = ccNum;

          this.cvv = cvv;

          this.dateOfExpiry = expiryDate;

     }



     @Override

     public void pay(int amount) {

          System.out.println(amount + " paid with credit/debit card");

     }



}

public class Item {



     private String upcCode;

     private int price;



     public Item(String upc, int cost) {

          this.upcCode = upc;

          this.price = cost;

     }



     public String getUpcCode() {

          return upcCode;

     }



     public int getPrice() {

          return price;

     }



}

public class ShoppingCart {



     // List of items

     List<Item> items;



     public ShoppingCart() {

          this.items = new ArrayList<Item>();

     }



     public void addItem(Item item) {

          this.items.add(item);

     }



     public void removeItem(Item item) {

          this.items.remove(item);

     }



     public int calculateTotal() {

          int sum = 0;

          for (Item item : items) {

              sum += item.getPrice();

          }

          return sum;

     }



     public void pay(PaymentStrategy paymentMethod) {

          int amount = calculateTotal();

          paymentMethod.pay(amount);

     }

}

public class ShoppingCartTest {



     public static void main(String[] args) {

          ShoppingCart cart = new ShoppingCart();



          Item item1 = new Item("1234", 10);

          Item item2 = new Item("5678", 40);



          cart.addItem(item1);

          cart.addItem(item2);



          // pay by paypal

          cart.pay(new PaypalStrategy("[email protected]", "mypwd"));



          // pay by credit card

          cart.pay(new CreditCardStrategy("Saeed Gharibi", "1234567890123456",

                   "786", "12/15"));

     }



}

50 paid using Paypal.
50 paid with credit/debit card