Transfer.java

// Transfer.java
// Represents a transfer ATM transaction

public class Transfer extends Transaction{
    
   private Keypad keypad; // reference to keypad
   private Screen screen; // reference to screen
   private int accountNumber; // indicates Transferor account involved
   private int transfereeAccountNumber; // indicates transferee account involved
   private BankDatabase bankDatabase; // account info database
   private double amount; // amount to deposit
   private final static int CANCELED = 0; // constant for cancel option
   
   // Transfer constructor
   public Transfer( int userAccountNumber, Screen atmScreen, 
      BankDatabase atmBankDatabase, Keypad atmKeypad )
   {
      // initialize superclass variables
      super( userAccountNumber, atmScreen, atmBankDatabase );

      accountNumber = userAccountNumber;
      screen = atmScreen;
      bankDatabase = atmBankDatabase;
      keypad = atmKeypad; // initialize references to keypad 
      transfereeAccountNumber = 0; // no current account number to start
      
   } // end Transfer constructor
   
    // Execute transfer for GUI
    public void executeGUI(int targetAccount, double amount) {
        BankDatabase bankDatabase = getBankDatabase();
        Screen screen = getScreen();

        // Validate the target account
        if (!bankDatabase.isValidAccount(targetAccount)) {
            screen.displayMessageLine("Target account does not exist.");
            return;
        }

        // Validate sufficient funds
        if (bankDatabase.getAvailableBalance(getAccountNumber()) < amount) {
            screen.displayMessageLine("Insufficient funds in your account.");
            return;
        }

        // Perform the transfer
        bankDatabase.debit(getAccountNumber(), amount); // Debit sender
        bankDatabase.credit(targetAccount, amount);     // Credit receiver

        screen.displayMessageLine("Transfer successful!");
    }
    
   @Override
   public void execute(){
    
     //Start inputing transferee account number
       while(bankDatabase.isValidAccount(transfereeAccountNumber) == false || transfereeAccountNumber == 0){
           
         //Exclude the base case
           if(transfereeAccountNumber != 0)
               screen.displayMessageLine( "\nThe transferee account you entered does not exist. Please Enter again. \n");
           
         //Input transferee account number
           screen.displayMessage( "\nPlease enter transferee account number" + 
                   "(or 0 to cancel): ");
           transfereeAccountNumber = keypad.getInput();  
           
         //Cancel transfer
           if(transfereeAccountNumber == CANCELED) 
               return;
           
         //Invalid Transfer account - transfering to Transferor's account
           if(transfereeAccountNumber == accountNumber) {
               screen.displayMessageLine( "\nYou cannot transfer to yourself. Please Enter again. \n");
               transfereeAccountNumber = 0;
           }
               
       }
       
       //Confirmation
       screen.displayMessage( "\nTransferee account number :" + transfereeAccountNumber);
       if(!isConfirmed()) 
           return;
       
           //Input amount to transfer
           amount = -1; // Initialize to an invalid state
               while (true) {
        screen.displayMessage("\nPlease enter a transfer amount in HK$ (or 0 to cancel): ");
        amount = keypad.getInputDouble();  

        // Cancel transfer
        if (amount == CANCELED) 
            return;

        // Check if the amount is valid
        if (amount <= 0.00) {
            screen.displayMessageLine("\nYou should enter a positive amount. Please enter again.\n");
        } else if (amount > bankDatabase.getAvailableBalance(accountNumber)) {
            screen.displayMessageLine("\nYou do not have enough money in your account. Please enter an amount less than or equal to your available balance.\n");
        } else {
            break; // Valid amount, exit the loop
        }
    }

                   
       screen.displayMessageLine( "\nTransferor account number: " + accountNumber );
       screen.displayMessageLine( "Transferee account number: " + transfereeAccountNumber );
       screen.displayMessage( "Transfer amount: ");
       screen.displayDollarAmount( amount );
       
       if(!isConfirmed()) 
           return;
       
       startTransfer();
   }
   
   public void startTransfer() {
       bankDatabase.debit(accountNumber, amount);
       bankDatabase.credit(transfereeAccountNumber, amount);
       
       screen.displayMessage("\nYou successfully transfered ");
       screen.displayDollarAmount(amount);
       screen.displayMessageLine(" to Account " + transfereeAccountNumber + ".");
       screen.displayMessage("Your remaining Available balance:");
       screen.displayDollarAmount( bankDatabase.getAvailableBalance(accountNumber) );
       screen.displayMessageLine( "" );
   }
   
   public boolean isConfirmed() {
       int confirmation = 0;
       screen.displayMessage( "\nPress any number (except 0) to confirm (or 0 to cancel): " );
       
       confirmation = keypad.getInput();
       
       if(confirmation == CANCELED)
           return false;
       
       return true;
   }
}