Java: transfering elements from one ArrayList to another ArrayList

Question

If I have a list of Products(an inventory):

public List<Product> productList = new ArrayList<>();

After a customer selects a given product for purchase, can I/how do I remove the product from productList(my inventory) and place it in another list (the customer's shoppingCart)? From here, if the customer decides he/she would not like to purchase the product (proceed to checkout) can I/how do I remove this product from shoppingCart & return it to productList?

Answer 1

You can use List.remove(Product) and List.add(Product) methods.

Just make sure that the equals method in Product class is implemented properly and because the remove() method removes the element from list if equals method returns true.

Answer 2

public List<Product> productList = new ArrayList<>();
public List<Product> shoppingCart = new ArrayList<Product>();

Customer selects the product

shoppingCart.add(p); //p is the product object

Check if the customer checks out

 boolean customerChecksOut = true;

 if(customerChecksOut)
 customerChecksOut(p);
 else
 customerDropsTheProduct(p);

 void customerChecksOut(Product p){
 productList.remove(p);
 }

 void customerDropsTheProduct(p)
 {
 shoppingCart.remove(p);
 }

You also need to override the equals & hashcode method in your product class.