Bank.java

/**
 * A Bank can hold up to a fixed number of BankAccounts.
 */
public class Bank {
    
    /** The array of BankAccount objects. */
    private BankAccount[] accounts;

    /** The first available account index. */
    private int firstAvailableAcc;

    /**
     * Creates a bank that can have up to numAccounts accounts.
     */
    public Bank(int numAccounts) {
        this.accounts = new BankAccount[numAccounts];
        this.firstAvailableAcc = 0;
    }

    /**
     * Adds the given BankAccount to the bank. If the bank is full
     * an error message is printed and the bank is unchanged.
     * @param account The account to add
     */
    public void add(BankAccount account) {
        if (firstAvailableAcc == accounts.length) {
            System.out.println("Bank is full. No account added.");
            return;
        }
        this.accounts[firstAvailableAcc] = account;
        firstAvailableAcc++;
        
    }

    /**
     * Returns the bank account with the given account number.
     * If no such account exists, null is returned.
     * @param acctNumber The account number
     * @return The account
     */
    public BankAccount find(int acctNumber) {
        for (int i = 0; i < firstAvailableAcc; i++) {
            if (accounts[i].getAccountNumber() == acctNumber) {
                return accounts[i];
            }
        }

        return null;
    }

    /**
     * Returns a string representation of the bank.
     * The format is one account per line.
     */
    public String toString() {
        if (firstAvailableAcc == 0) return "NONE";
        
        String result = "";
        for (int i = 0; i < firstAvailableAcc; i++) {
            result += accounts[i].getAccountNumber() + " ";
            result += accounts[i].getBalance() + "\n"; 
        // Note that we don't make use of BankAccount's toString because
        // we don't want to have dollar signs ($) as part of the String
        // representation for the Bank.
        }

        return result;
    }
}