Modeling the process of issuing receipts in a store(Java)

It is necessary to create classes that store and manipulate information about: cashier in a store; goods in a store; a store where goods are purchased and receipts are issued when a payment is registered in the store. Cashier class - stores information about the identification number and name of the cashier; Class Goods to be sold in a store - stores identification number, name, unit price of the goods and expiration date; Class Store - stores information about a list of goods sold in the store, a list of cashiers who work in the store and the number of issued receipts. Goods must be delivered to the store, which will then be sold. It must be possible to sell a product if there is a sufficient quantity of it available in the store. It should be possible to check at any time what the total turnover of the store is at the moment. The receipt must contain at least the following information: serial number, cashier issuing the receipt, date and time of issuance of the receipt, list of goods to be included in the receipt, including their price. It is necessary to keep the total number of issued receipts so far and the total amount generated as turnover at the time of issue. When issuing the receipt, it is necessary to display its contents and save them in a file. Each receipt must be kept in a separate file with the file name, which must contain the serial number of the issued receipt. It should be possible to check how many receipts have been issued at the moment. The information in the file in which the receipt is saved must be legible. When selling a product, check if there is enough of it available. If the quantity is not enough to throw an exception. The exception is to show what from which product what quantity is not enough to make the purchase. Two cash registers work in parallel in the store. To carry out the work of these two boxes in two separate threads. To show information about which cashier is currently working at the cash register and the total value of each issued cash receipt.