Return toString method, not returning what I want (Java)

Question

I have a project where I am creating a BankAccount superclas with a SavingsAccount subclass. Everything is working fine but I am having trouble returning the string I specifically want.

Example: (Trimmed Down)

public class BankAccount {
   public static final double MONTHS_IN_YEAR = 12.0;

   private String myCustomerName;
   private double myAccountBalance;
   private double myInterestRate;
   protected int myMonthlyWithdrawCount;
   protected double myMonthlyServiceCharges;

   public BankAccount(final String theNameOfOwner, 
                      final double theInterestRate) {
      myCustomerName = theNameOfOwner;
      myAccountBalance = 0.0;
      myInterestRate = theInterestRate;
      myMonthlyWithdrawCount = 0;
      myMonthlyServiceCharges = 0.0;
   }

   public String toString() {
      String result = "";
      result += String.format("BankAccount[owner: %s, balance: %.2f,",
                               myCustomerName, myAccountBalance);
      result += String.format(" interest rate: %.2f,", myInterestRate);
      result += String.format("\n\t\t  ");
      result += String.format("number of withdrawals this month: %d,",
                               myMonthlyWithdrawCount);
      result += String.format(" service charges for this month: %.2f]",
                               myMonthlyServiceCharges);
      return result;         
   }
}

The driver class will use the toString method for BankAccount and it prints this:

BankAccount[owner: John Doe, balance: 0.00, interest rate: 0.05,
          number of withdrawals this month: 0, service charges for this                month: 0.00] 

(Which is perfect for this superclass)

However, here comes the subclass SavingsAccount

public class SavingsAccount extends BankAccount {
   public static final double SAVINGS_THRESHOLD = 25.0;

   private boolean myStatusIsActive;

   public SavingsAccount(final String theNameOfOwner, 
                         final double theInterestRate) {
      super(theNameOfOwner, theInterestRate);
      myStatusIsActive = false;
      if (super.getBalance() >= SAVINGS_THRESHOLD) {
         myStatusIsActive = true;
      }
   }

   public String toString() {
      String result = "";
      result += "SavingsAccount";
      result += super.toString();
      return result;
   }
}

When calling the toString method of SavingsAccount, it prints:

SavingsAccountBankAccount[owner: Dan Doe, balance: 0.00, interest rate: 0.05, number of withdrawals this month: 0, service charges for this month: 0.00]

(I don't want the BankAccount to be included, I just want it to print the "SavingsAccount" header then goes directly to "[owner: Dan Doe,"

I've tried having it return "SavingsAccount" first which it does correctly, but when calling super.toString(), it also ends up returning the BankAccount header which I don't want.

Any ideas on how I could fix this issue?

Answer 1

A few options I can think of:

1. Replace "BankAccount" with "SavingsAccount" instead of just appending it:

   @Override
   public String toString() {
       return super.toString().replaceFirst("BankAccount", "SavingsAccount");
   }
   

2. Move the details portion into its own method, and call it from each toString() with the appropriate header:

   // BankAccount.java
   @Override
   public String toString() {
       return "BankAccount" + getDetailsString();
   }
   
   protected String getDetailsString() {
       String result = String.format("[owner: %s, balance: %.2f,",
               myCustomerName, myAccountBalance);
       // ...
       return result;
   }
   
   // SavingsAccount.java
   @Override
   public String toString() {
       return "SavingsAccount" + getDetailsString();
   }
   

3. Get the runtime class name in the superclass so it doesn't need to be overridden altogether:

   @Override
   public String toString() {
       String result = String.format("%s[owner: %s, balance: %.2f,",
               getClass().getSimpleName(), myCustomerName, myAccountBalance);
       // ...
       return result;
   }