      1  import java.io.Serializable;

      2  import java.util.ArrayList;

      3

      4  /**

      5     This bank contains a collection of bank accounts.

      6  */

      7  public class Bank implements Serializable

      8  {

      9     private ArrayList<BankAccount> accounts;

     10

     11     /**

     12        Constructs a bank with no bank accounts.

     13     */

     14     public Bank()

     15     {

     16        accounts = new ArrayList<BankAccount>();

     17     }

     18

     19     /**

     20        Adds an account to this bank.

     21        @param a the account to add

     22     */

     23     public void addAccount(BankAccount a)

     24     {

     25        accounts.add(a);

     26     }

     27

     28     /**

     29        Finds a bank account with a given number.

     30        @param accountNumber the number to find

     31        @return the account with the given number, or null if there

     32        is no such account

     33     */

     34     public BankAccount find(int accountNumber)

     35     {

     36        for (BankAccount a : accounts)

     37        {

     38           if (a.getAccountNumber() == accountNumber) // Found a match

     39           {

     40              return a;

     41           }

     42        }

     43        return null; // No match in the entire array list

     44     }

     45  }