1  /**

  2     A checking account that charges transaction fees.

  3  */

  4  public class CheckingAccount extends BankAccount

  5  {  

  6     private static final int FREE_TRANSACTIONS = 3;

  7     private static final double TRANSACTION_FEE = 2.0;

  8  

  9     private int transactionCount;

 10  

 11     /**

 12        Constructs a checking account with a given balance.

 13        @param initialBalance the initial balance

 14     */

 15     public CheckingAccount(double initialBalance)

 16     {  

 17        // Construct superclass

 18        super(initialBalance);

 19        

 20        // Initialize transaction count

 21        transactionCount = 0; 

 22     }

 23  

 24     public void deposit(double amount) 

 25     {  

 26        transactionCount++;

 27        // Now add amount to balance 

 28        super.deposit(amount); 

 29     }

 30     

 31     public void withdraw(double amount) 

 32     {  

 33        transactionCount++;

 34        // Now subtract amount from balance 

 35        super.withdraw(amount); 

 36     }

 37  

 38     /**

 39        Deducts the accumulated fees and resets the

 40        transaction count.

 41     */

 42     public void deductFees()

 43     {  

 44        if (transactionCount > FREE_TRANSACTIONS)

 45        {  

 46           double fees = TRANSACTION_FEE *

 47                 (transactionCount - FREE_TRANSACTIONS);

 48           super.withdraw(fees);

 49        }

 50        transactionCount = 0;

 51     }

 52  }