Design Pattern - Strategy

Main.Java

public class Main {

    public static void main(String[] args) {
        ShoppingCart shoppingCart = new ShoppingCart();

        Item itemOne = new Item(23);
        Item itemTwo = new Item(42);

        shoppingCart.addItemToShoppingCart(itemOne);
        shoppingCart.addItemToShoppingCart(itemTwo);

        shoppingCart.pay(new CreditCardStrategy("Tobas", "123", "123", "Visa", "16/25"));

    }

}

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ShoppingCart.Java

import java.util.ArrayList;
import java.util.List;

public class ShoppingCart {
    private List<Item> items;

    public ShoppingCart(){
        this.items = new ArrayList<Item>();
    }

    public void addItemToShoppingCart(Item item){
        items.add(item);
    }

    public void removeItemFromShoppingCart(Item item){
        items.remove(item);
    }

    public int calculateTotalPrice(){
        int sum = 0;

        for(Item item : items){
            sum += item.getPrice();
        }
        return sum;
    }

    public void pay(PaymentStrategy paymentMethod){
        int amount = calculateTotalPrice();
        paymentMethod.pay(amount);
    }
}

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Item.Java


public class Item {
    private int price;

    public Item(int price){
        this.price = price;
    }

    public int getPrice(){
        return this.price;
    }
}

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PayPalStrategy.Java

public class PayPalStrategy implements PaymentStrategy{

    private String userName;
    private String password;

    public PayPalStrategy(String userName, String password) {
        this.userName = userName;
        this.password = password;
    }

    @Override
    public void pay(int amount) {
        System.out.println(amount + " paid with PayPal");
    }

}

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CreditCardStrategy.java

public class CreditCardStrategy implements PaymentStrategy{

    private String cardHolderName;
    private String cardNumber;
    private String cvv;
    private String cardProvider;
    private String dateOfExpiry;

    public CreditCardStrategy(String cardHolderName, String cardNumber, String cvv, String cardProvider, String dateOfExpiry) {
        this.cardHolderName = cardHolderName;
        this.cardNumber = cardNumber;
        this.cvv = cvv;
        this.cardProvider = cardProvider;
        this.dateOfExpiry = dateOfExpiry;
    }

    @Override
    public void pay(int amount) {
        System.out.println(amount + " paid with Credit Card");
    }

}

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PaymentStrrategy.Java

public interface PaymentStrategy {
    public void pay(int amount);
}