Java Community | Help. Code. Learn.•11mo ago

need to handle it when the stock is null

everything works but when the stock == 0 it java.lang.NullPointerException: Cannot invoke "com.example.todoappdeel3.models.OrderProduct.getQuantity()" because "orderProduct" is null get stuck

109 Replies

JavaBot•11mo ago

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TimoOP•11mo ago

TimoOP•11mo ago

id 3 and stock 0 so only happens when stock is 0 but no clue how to fix it

dan1st•11mo ago

Can you show how you are getting it from the DB? and check what exactly is null with a debugger

TimoOP•11mo ago

like the payload?

dan1st•11mo ago

I meant debugging the backend code when retrieving it where you get the NPE

TimoOP•11mo ago

ok give me 1 min

dan1st•11mo ago

Is that where the NPE is thrown?

TimoOP•11mo ago

what is a NPE?

dan1st•11mo ago

NullPointerException

TimoOP•11mo ago

if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1); this is the line where it breaks

dan1st•11mo ago

In that code, use a debugger and check the value of order and product especially the ids with the quantity being 0

TimoOP•11mo ago

not used to the debugger just know that is always breaks when the stock is 0

dan1st•11mo ago

Can you show me the values of the ids in that case (from the debugger)? As well as the corresponding database entry

TimoOP•11mo ago

like those or different ids?

dan1st•11mo ago

order.id and product.id in that Java code

TimoOP•11mo ago

but here it just finds the whole thing right so also the ids like evrything that has to do with the product

dan1st•11mo ago

Well there's something you are not expecting so I'm asking you to check the details that should be there

TimoOP•11mo ago

but do you wanna see my models or dto's ? im confused

dan1st•11mo ago

set a breakpoint in the final OrderProduct orderProduct column check both order and product step one line further and check whether orderProduct is null as well as show me the corresponding DB entry

TimoOP•11mo ago

dan1st•11mo ago

Can you expand product and order?

TimoOP•11mo ago

dan1st•11mo ago

In the priduct_order table Is there an entry with both of them being 0? 1* an entry with both product and order id being wrong

TimoOP•11mo ago

dan1st•11mo ago

Is this one that works?

TimoOP•11mo ago

no that is just when you place an order the problem is when you are trying to retout retour

dan1st•11mo ago

Can you show me the above information of an example that doesn't work?

TimoOP•11mo ago

order product is basically the products in the order but if you retour for example it is -1

dan1st•11mo ago

So where does the exception occur?

TimoOP•11mo ago

here

dan1st•11mo ago

Can you place a breakpoint there and debug it? and is that the code giving you the orderProduct for that?

TimoOP•11mo ago

4 repos in total 1 find user 2 find order id 3 find product id 4 combine the order with the product

TimoOP•11mo ago

dan1st•11mo ago

Can you please just show me the whole file containing the if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1); in a codeblock (not using an image) as well as put a breakpoint in that if?

TimoOP•11mo ago

pastebin ok cuz it is too big

dan1st•11mo ago

then just show the method the complete method

TimoOP•11mo ago

@Transactional
    public RetourDTO createRetour(RetourDTO retourDTO, String userName) {
        final CustomUser customUser = userRepository.findByEmail(userName).orElseThrow();

        final Order order = orderRepository.findById(retourDTO.getOrderId()).orElseThrow();
        final Product product = productRepository.findById(retourDTO.getOrderProductId()).orElseThrow();

        // if the order does not exist -> error
        // if item not in order -> error
        final OrderProduct orderProduct = orderProductRepository.findByOrderAndProduct(order, product);

        // decrement item quantity

        if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

        final Retour retour = Retour
            .builder()
            .order(order)
            .status("placed")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(orderProduct.getProduct())
            .date(LocalDate.now())
            .build();
        retourRepository.save(retour);
        orderProductRepository.save(orderProduct);

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

        return retour.getDto();
    }

@Transactional
    public RetourDTO createRetour(RetourDTO retourDTO, String userName) {
        final CustomUser customUser = userRepository.findByEmail(userName).orElseThrow();

        final Order order = orderRepository.findById(retourDTO.getOrderId()).orElseThrow();
        final Product product = productRepository.findById(retourDTO.getOrderProductId()).orElseThrow();

        // if the order does not exist -> error
        // if item not in order -> error
        final OrderProduct orderProduct = orderProductRepository.findByOrderAndProduct(order, product);

        // decrement item quantity

        if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

        final Retour retour = Retour
            .builder()
            .order(order)
            .status("placed")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(orderProduct.getProduct())
            .date(LocalDate.now())
            .build();
        retourRepository.save(retour);
        orderProductRepository.save(orderProduct);

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

        return retour.getDto();
    }

dan1st•11mo ago

Now for a product/order combination that's an issue (where you get the NPE), place a breakpoint in if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1); and show me: - orderProduct - the expanded order - the expanded product - the corresponding entry in the DB table (where the quantity is 0 I assume) And I think I found that problem

TimoOP•11mo ago

yeah just dunno how to fix it XD

dan1st•11mo ago

You are deleting the entry in the table if the quantity is 0

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

So when you call orderProductRepository.findByOrderAndProduct(order, product), there is no entry for it in the DB

TimoOP•11mo ago

but how should i fix it then cuz want to delete from the orderproducts

TimoOP•11mo ago

so i can change teh status

dan1st•11mo ago

You can just change what happens after orderProductRepository.findByOrderAndProduct(order, product) What should happen if there's no entry in the DB?

TimoOP•11mo ago

it should still work cuz the stock has nothing to do with the retour

dan1st•11mo ago

what should happen? "it should work" is not a description of what should happen

TimoOP•11mo ago

it should also be able to sent a product on retour wich has a stok of 0

dan1st•11mo ago

I have no idea what that means. Does that mean it should send back the same response (with the Retour.builder()) and do nothing else with the DB?

TimoOP•11mo ago

i mean the onlu thing that changes it the order product not the product itself so right now it can t find the product so it should just be able to find the product and if you retour the quantity should go down until there are no items in the retour left

dan1st•11mo ago

and what should happen if there is nothing left? Should anything change in that case?

TimoOP•11mo ago

then it is just empty and the status changes

  // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

  // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

dan1st•11mo ago

ok So after final OrderProduct orderProduct = orderProductRepository.findByOrderAndProduct(order, product);, you can do an if(orderProduct == null) In that if, you put all the logic that should happen if the quantity is 0 i.e. you do the order.setStatus("retour and empty"); and orderRepository.save(order);

TimoOP•11mo ago

yeah tried that but couldn t get that to work

dan1st•11mo ago

And then you need to decide what to return in that case

TimoOP•11mo ago

cuz the quantity in the orderproduct in 1 if the stock of the product is 0

dan1st•11mo ago

I have no idea why that would be a problem You said you want this to happen when trying to use that endpoint and the quantity is already 0 and that's exactly what the if is checking

TimoOP•11mo ago

yeah? but it isn t working im confused lol

dan1st•11mo ago

- You need to decide what you want to return if it's empty, else it won't work - I can't help you if you don't tell me what's broken

TimoOP•11mo ago

1 just change the status if it is empty like the other products 2 you know what is broken right?

dan1st•11mo ago

1 and what do you want the response to be? 2 no, I neither no what exactly you do with the if I told you about nor do I know what happens

TimoOP•11mo ago

can show you an example with a working product

dan1st•11mo ago

The important thing to know is what should happen if the quantity is 0 already already meaning before the request and what should be the response to the user in that case

TimoOP•11mo ago

this should happen if the retour works fine it breaks with the stock but i don t know excactly either how to fix it cuz otherwise i wouldn t create a post 😅 :boohoo:

dan1st•11mo ago

What about that changed? What should be sent back to the user? I could make guesses that would result in you not getting the exception but I'd have no idea whether that's what you actually want

TimoOP•11mo ago

orderproduct == empty when there is no products order status is retour and empty and in retour there is info

dan1st•11mo ago

You mean they should get a Retour object with status set to empty?

TimoOP•11mo ago

that is the order because if there are no products in orderprodtc that means that the retour is empty and the status changes

dan1st•11mo ago

if(orderProduct == null) {
    order.setStatus("retour and empty");
    orderRepository.save(order);
    final Retour retour = Retour
            .builder()
            .order(order)
            .status("empty")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(product)
            .date(LocalDate.now())
            .build();
    return retour.getDto();
}

if(orderProduct == null) {
    order.setStatus("retour and empty");
    orderRepository.save(order);
    final Retour retour = Retour
            .builder()
            .order(order)
            .status("empty")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(product)
            .date(LocalDate.now())
            .build();
    return retour.getDto();
}

Like that?

TimoOP•11mo ago

yeah kinda ig but the thing is that it is not empty because the is a product in the order

 if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

 if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

so this hdanles it of normally but won t work with 0

dan1st•11mo ago

I have no idea what that means If you enter that if, you know there is no entry in the DB so you know the quantity is 0

TimoOP•11mo ago

yeah but with null it is still in the order id and the quantity gets sent in as 1

TimoOP•11mo ago

orderproduct is 1 while the stock == 0

dan1st•11mo ago

TimoOP•11mo ago

the stock is 0 of the product but the quantity in the order is 1

dan1st•11mo ago

How is that related to the issue?

TimoOP•11mo ago

because it blocks when the stock is 0 but i still wanna remove the quantity

dan1st•11mo ago

What blocks if the stock is 0? What do you want to do if there is no stock but the quantity is nonzero?

TimoOP•11mo ago

Then i Just want it to work like the rest that is the problem

dan1st•11mo ago

What does that mean? Should it do exactly the same as if it was in stock?

TimoOP•11mo ago

Yeah

dan1st•11mo ago

Can you show the code? with the changes you made

TimoOP•11mo ago

I have made none for now

dan1st•11mo ago

You did that, right?

TimoOP•11mo ago

Why do i want to do that for both?

dan1st•11mo ago

That's not what I said You made a change and I asked to see the code with the changes you did so I can see what exactly you are doing

TimoOP•11mo ago

    @Transactional
    public RetourDTO createRetour(RetourDTO retourDTO, String userName) {
        final CustomUser customUser = userRepository.findByEmail(userName).orElseThrow();

        final Order order = orderRepository.findById(retourDTO.getOrderId()).orElseThrow();
        final Product product = productRepository.findById(retourDTO.getOrderProductId()).orElseThrow();

        // if the order does not exist -> error
        // if item not in order -> error
        final OrderProduct orderProduct = orderProductRepository.findByOrderAndProduct(order, product);

        // decrement item quantity

        if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

        final Retour retour = Retour
            .builder()
            .order(order)
            .status("placed")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(orderProduct.getProduct())
            .date(LocalDate.now())
            .build();
        retourRepository.save(retour);
        orderProductRepository.save(orderProduct);

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

        return retour.getDto();
    }

    @Transactional
    public RetourDTO createRetour(RetourDTO retourDTO, String userName) {
        final CustomUser customUser = userRepository.findByEmail(userName).orElseThrow();

        final Order order = orderRepository.findById(retourDTO.getOrderId()).orElseThrow();
        final Product product = productRepository.findById(retourDTO.getOrderProductId()).orElseThrow();

        // if the order does not exist -> error
        // if item not in order -> error
        final OrderProduct orderProduct = orderProductRepository.findByOrderAndProduct(order, product);

        // decrement item quantity

        if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

        final Retour retour = Retour
            .builder()
            .order(order)
            .status("placed")
            .customUser(customUser)
            .reason(retourDTO.getReason())
            .product(orderProduct.getProduct())
            .date(LocalDate.now())
            .build();
        retourRepository.save(retour);
        orderProductRepository.save(orderProduct);

        if(orderProduct.getQuantity() == 0) {
            order.getOrderProducts().remove(orderProduct);
            orderProductRepository.delete(orderProduct);
        }

        // if no items in order, then delete order
        if(order.getOrderProducts().isEmpty()) {
            // orderRepository.delete(order);
            order.setStatus("retour and empty");
            orderRepository.save(order);
        }

        return retour.getDto();
    }

dan1st•11mo ago

Didn't you add a null check? where's that?

TimoOP•11mo ago

little bit below but isn t that sort of double?

TimoOP•11mo ago

dan1st•11mo ago

If you put it below, you'll still get the NPE you'd need to put it before if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

TimoOP•11mo ago

like this? .product(orderProduct.getProduct()) is null

dan1st•11mo ago

just add that before your if(orderProduct.getQuantity() > 0) orderProduct.setQuantity(orderProduct.getQuantity() - 1);

TimoOP•11mo ago

Fixed it The problem lied elsewhere thank you for helping apreciate it !

JavaBot•11mo ago

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TimoOP•11mo ago

Thank you is a keyword?

dan1st•11mo ago

yeah, the bot reacts to it

JavaBot•11mo ago

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need to handle it when the stock is null

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