연습문제

BankException
마이너스 입금 불가, 코드값 1000
마이너스 출금 불가, 코드값 2000
잔액보다 큰 출금 불가, 코드값 2001
deposit() throws BankException
sithdrawal() throws BankException
transfer() throws BankException

Bank 클래스

public class Bank {
	private String accNo;
	private long balance;
	public Bank(String accNo, long balance) {
		super();
		this.accNo = accNo;
		this.balance = balance;
	}
	public void deposit(long money) throws BankException {
		if(money < 0) {
			throw new BankException("마이너스 입금 불가", 1);
		}
		balance += money;
	}
	public long withdrawal(long money) throws BankException {
		if(money < 0) {
			throw new BankException("마이너스 출금 불가", 2);
		} else if(balance < money) {
			throw new BankException("잔액 부족", 3);
		}
		balance -= money;
		return money;
	}
	public void transfer(Bank acc, long money) throws BankException {
		acc.deposit(withdrawal(money));
	}
	public void inquiry() {
		System.out.println(this);
	}
	@Override
	public String toString() {
		return "Bank [accNo=" + accNo + ", balance=" + balance + "]";
	}	
}

BankException 클래스

public class BankException extends Exception {
	private static final long serialVersionUID = -3990936769640382913L;
	private int errorCode;
	public BankException(String message, int errorCode) {
		super(message);
		this.errorCode = errorCode;
	}
	public int getErrorCode() {
		return errorCode;
	}
	public void setErrorCode(int errorCode) {
		this.errorCode = errorCode;
	}
}

Main 클래스

public class Main {
	public static void main(String[] args) {
		Bank me = new Bank("1111", 10_000);
		Bank mom = new Bank("2222", 100_000);
		try {
			mom.transfer(me, 50_000);
		} catch (BankException e) {
			System.out.println(e.getMessage() + "," + e.getErrorCode());
		}
		me.inquiry();
		mom.inquiry();
	}
}

출력:
Bank [accNo=1111, balance=60000]
Bank [accNo=2222, balance=50000]

• 아무도 try-catch를 안할수도 있다.

public static void main(String[] args) throws BankException {