#256 ATM Implementation with a Contract

Write an ATM class according to the contract:

/**
 * ATM.
 * Interacts with the SDK whose contracts are described below.
 * Implement a request for dispensing a specified amount in rubles.
 * If the required amount cannot be dispensed, return a refusal.
 * Supported denominations: 50₽, 100₽, 500₽, 1000₽, 5000₽.
 */
class ATM {
    // place for code
}


/**
 * The SDK interface may be changed or extended by agreement between the parties if necessary.
 */
interface Sdk {
    /**
     * Count the number of banknotes of a particular denomination in the ATM.
     * This operation takes about 10 seconds and is noisy, so it should be called as rarely as possible.
     *
     * @param banknote banknote denomination
     * @return number of banknotes in the ATM
     */
    int countBanknotes(int banknote);

    /**
     * Move a specified number of banknotes of one denomination to the dispenser tray.
     *
     * @param banknote banknote denomination
     * @param count    number of banknotes
     */
    void moveBanknoteToDispenser(int banknote, int count);

    /**
     * Open the dispenser tray.
     */
    void openDispenser();
}

/**
 * Example SDK implementation that can be used in tests.
 * The implementation may and should be changed.
 */
class StubSdk implements Sdk {
    @Override
    public int countBanknotes(int banknote) {
        return 0;
    }

    @Override
    public void moveBanknoteToDispenser(int banknote, int count) {
        System.out.printf("Moving banknote %s to the dispenser tray, %s banknotes%n", banknote, count);
    }

    @Override
    public void openDispenser() {
        System.out.printf("The dispenser tray is open for the user%n");
    }
}