The solution of the problem includes modeling and realization of the process of issuing
cash receipts in the store. It is necessary to create classes that store and
manipulate information about: store; cashier in a store; goods in a store; cash register in a store;
a receipt that is issued to the customer.
1. Cashier class – stores information about the identification number and name of the cashier;
2. Class Goods to be sold in a store – stores identification number, name,
unit price of the goods and expiration date;
3. Class Cashier in a store – stores information about which cashier is currently working
this safe. At the checkout, customers in the store pay for the purchased goods and receive
receipt. 4. Class The receipt must contain at least the following information: sequential
number, cashier who issues the receipt, date and time of issuance of the receipt
a note, a list of goods to be included in the receipt including the price and
their quantity. It is necessary to keep the total number of issued cash registers
notes to date and the total amount generated as turnover at issue.
When issuing the receipt, it is necessary to display its contents
and save to file. Each receipt must be kept in a separate name file
of the file, which should contain the serial number of the issued receipt.
You have to be able to check how many cash receipts are issued at the moment. The information
it must be legible in the file in which the receipt is saved. 5. 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 cash registers
notes. Goods must be delivered to the store, which will then be sold.
It must be possible to sell goods if there is enough available
quantity of it in the store. It must be possible to check at any time
what is the total turnover of the store at the moment.

Realization requirements:
1. When selling goods, check that there is a sufficient quantity of
her. If the quantity is not enough to throw an exception. The exception is yes
indicates from which product what quantity is not enough to make the purchase.
2. In the store all cash registers work in parallel. To carry out the work of the cash registers in
individual threads. Display information about which cashier works at the cash register in
the moment and the total value of each issued receipt.
3. The application must be developed in Java and allow the data to
meets the requirements described above