Blanking out a button if they do not have enough funds in their bank.

[Brian O'Connor]

Hey guys, im new to java and am wanting to disable a button say "20" if they do not have enough funds in their bank. I have had a shot at it but i keep getting "operator cannot be applied to java.lang.string,double. I'm pretty sure im missing something simple here.. =(

public class ATMWithdraw extends JPanel
                      implements ActionListener {
// Declare string variables for use in GUI
    private static String AU20 = "20";
    private static String AU50 = "50";
    private static String AU100 = "100";
    private static String AU200 = "200";
    private static String AU300 = "300";
    private static String OTHER = "other";
    private static String AMOUNT = "amount";
// Declare JButton variables for use in GUI    
    private static JButton au20Button, au50Button, au100Button, 
                            au200Button,au300Button, otherButton;
// Declare object variables for use in GUI
    private JFrame controllingFrame; //needed for dialogs
    protected JTextField amountTextField;
    protected JLabel amountLabel;
    private ATMDataFile atmData;
    private ATM atm;
  
// Constructor method - called from ATM with ATMframe as the argument f
// an ATMWithdrawl object is created as a subtype of a JPanel
    public ATMWithdraw(JFrame f) {
        controllingFrame = f;
     
        JComponent titlePane = createTitlePane();
        add(titlePane);     // add the titlepane to the ATMWithdraw JPanel
  // Call the createButtonPanel method to populate the button pane        
        JComponent buttonPane = createButtonPanel();
        add(buttonPane);
  // Call the createBotTextPane method to populate the text box pane pane
        JComponent botTextPane = createBotTextPane();
        add(botTextPane);
    }

// "actionPerformed" method - reads the action command "cmd"
//    set by the button and text field components and selected 
//    by the users mouse click or text entry
//    and selects the action to perform
    public void actionPerformed(ActionEvent e) {
        String cmd = e.getActionCommand(); //gets "cmd" if button clicked
        String input = amountTextField.getText(); //gets "input" from text entry 
        if (OTHER.equals(cmd)){             // Other amount button pressed.
          amountTextField.setEnabled(true); // enable text entry
          amountLabel.setEnabled(true); 
          au20Button.setEnabled(false);     // disable (grey out) other buttons
          au50Button.setEnabled(false);
          au100Button.setEnabled(false);
          au200Button.setEnabled(false);
          au300Button.setEnabled(false);
          otherButton.setEnabled(false);
          amountTextField.requestFocusInWindow();  //set focus to text entry

        } else if (AMOUNT.equals(cmd)) {           // User enters other amount.
            //Test if the entered ammount is a multiple of $20
            // by using the "mod" opperation to divide by 20 and find the remainder
            BigInteger remainder = (new BigInteger(input)).mod 
                                    (new BigInteger("20"));
            // Test if remainder is "0"
            if (remainder.equals((new BigInteger("0")))) {    // Yes it's a multiple
              JOptionPane.showMessageDialog(controllingFrame, // pop up a success message
                    "$"+input +" is a multiple of $20\n"
                    +"Well done!!");
              // Invoke the "tryWithdrawl" method 
              //   with the entered ammount as the argument      
              tryWithdrawl(input);  
              
            } else {                                         // Not a multiple of $20
                JOptionPane.showMessageDialog(controllingFrame,  // pop up a failure message
                    "$"+input +" is not a multiple of $20\n"
                    +"Try again dickhead!!",
                    "Error Message",
                    JOptionPane.ERROR_MESSAGE);           
            }
        } else {        // User pressed a value button
            int buttonValue = (new Integer(cmd)).intValue();
            switch (buttonValue) {
                case 20:  tryWithdrawl(cmd); break;
                case 50:  tryWithdrawl(cmd); break;
                case 100:  tryWithdrawl(cmd); break;
                case 200:  tryWithdrawl(cmd); break;
                case 300:  tryWithdrawl(cmd); break;
             
            
            
            
            }   
           double currentBalance= 
            (new Double (atmData.getBalance())).doubleValue(); 
             if (input <= currentBalance) {
              au20Button.setEnabled(false); 
            }
        }
// "tryWithdrawl" method calls ATMData.doWithdrawl and process results
    protected void tryWithdrawl(String in) {
    // run the doWithdrawl method on the ATMData object
    // this method returns the amount remaining in the account 
    // which is stored in the newBalance variable
    String newBalance = atmData.doWithdrawl(in);

      if (newBalance.isEmpty()) {           //Not enough cash
          // Display an error message 
          JOptionPane.showMessageDialog(controllingFrame,
                    "You don't have $"+in +" to withdraw.\n"
                    +"Bummer dude!! Try again.",
                    "Error Message",
                    JOptionPane.ERROR_MESSAGE);
                  
                          
      } else {                              // withdrawl OK
          // Go back to the balance display screen by invoking the 
          // balanceGUI method on the atm object
          atm.balanceGUI();      
      }
    }    
// Methods to populate the title pane, button pane 
//  and bottom text entry pane with text, buttons and 
//  text entry components. These methods are called from the 
//  class constructor method which also adds them to the atm frame.
//  These are written as seperate methods to seperate the "messy and confusing"
//  GUI componentry from the actual processes conducted by this class.
 
    protected JComponent createTitlePane() {
        JPanel t = new JPanel(new GridLayout(0,1));

        JLabel topLabel = new JLabel("Select amount to withdraw: ");
        t.add(topLabel); 
        
        return (t);
    }

        
    protected JComponent createButtonPanel() {
        JPanel p = new JPanel(new GridLayout(0,2));

        au20Button = new JButton("$20");
        au20Button.setActionCommand(AU20);
        au20Button.addActionListener(this);
        p.add(au20Button);

        au200Button = new JButton("$200");
        au200Button.setActionCommand(AU200);        
        au200Button.addActionListener(this);
        p.add(au200Button);
        
        au50Button = new JButton("$50");
        au50Button.setActionCommand(AU50);       
        au50Button.addActionListener(this);
        p.add(au50Button);

        au300Button = new JButton("$300");
        au300Button.setActionCommand(AU300);   
        au300Button.addActionListener(this);        
        p.add(au300Button); 
        
        au100Button = new JButton("$100");
        au100Button.setActionCommand(AU100);        
        au100Button.addActionListener(this);
        p.add(au100Button);
            
        otherButton = new JButton("Choose another amount");
        otherButton.setActionCommand(OTHER);
        otherButton.addActionListener(this);
        p.add(otherButton);

        return p;
    }
    
    protected JComponent createBotTextPane() {
        JPanel b = new JPanel(new FlowLayout(FlowLayout.TRAILING));   

        amountTextField = new JTextField(5);
        amountTextField.setActionCommand(AMOUNT);
        amountTextField.addActionListener(this);
        amountTextField.setEnabled(false);
        
        amountLabel = new JLabel("Type withrawal amount (multiples of $20 only)");
        amountLabel.setLabelFor(amountTextField);
        amountLabel.setEnabled(false);
        
        b.add(amountLabel);
        b.add(amountTextField);

        return (b);
    }
        
}

import java.io.*;
import java.util.Scanner;

public class ATMDataFile {
  public static String datafilename = "ATMData.txt";
  public static int lines = 0; // Number of lines in ATMdata.txt
  public static int lineNo; // Line number of the opperative account
  public static int lineTo;
  // Create a File object called "datafile" to see if "ATMdata.txt" exists
  static File datafile = new File(datafilename);
  // Declare a 2 dimensional array to hold account details
  // First three values are only used if no datafile exists.
  static String[][] account_inf = {{"John","Savings","12345","4444","100"},
                                  {"Jack","Cheque","54321","0000","100"},
                                  {"Sam","Manager","01234","0000","100"},
                                  {null,null,null,null,null},
                                  {null,null,null,null,null},
                                  {null,null,null,null,null},
                                  {null,null,null,null,null}};  

  public ATMDataFile() throws IOException { 
    // If ATMdata.txt exists run loadData method                 
    if (datafile.exists()) {
      loadData();
      // Debug code
      //writeFile();
      // If no datfile exists run the writeNewFile method
    } else {
         writeNewFile();
    }
  }

  // method for loading ATMdata.txt to a 2 dimensional array
  static void loadData()throws IOException {
    Scanner scan = null;
    BufferedReader read = null;
    try {
      // Create Scanner (reads text files one space delimeted element at a time)
      // and BufferedReader (reads contents of a text file into memory) objects 
      scan = new Scanner(new BufferedReader(new FileReader(datafile.getName())));
      read = new BufferedReader(new FileReader(datafile.getName()));
      // Count the number of lines in ATMdata.txt
      String l;
      while ((l = read.readLine()) != null) {
          lines ++ ;
      }
      // Debug code
      System.out.println ("Lines =" +lines);
      // Populate the 2 dimensional array account_inf with contents of 
      // ATMdata.txt. account_inf[0][0] is 1st account number
      //              account_inf[0][1] is 1st account pasword
      //              account_inf[0][2] is 1st account balance  
      //              account_inf[1][0] is 2nd account number etc...
      for(int i=0; i<=lines-1; i++){
        for(int j=0; j<=4; j++){
          account_inf[i][j] = scan.next();
          // Debug code
          System.out.print(" [" +i +"][" +j +"]=" 
                              +account_inf[i][j]);
        }
        // Debug code      
        System.out.println();
      }                
    } catch (IOException e) {
      System.err.println("Caught IOException: " 
                              +  e.getMessage());
      } finally {
        if (scan != null) {
            scan.close();
        }
      }
    }

  static void writeNewFile()throws IOException {
    String name = account_inf[0][0];
    String account_typ = account_inf[0][1];
    String account_no = account_inf[0][2];
    String password = account_inf[0][3];
    String balance = account_inf[0][4];
    PrintWriter out = null;
    try {
      // Create an output stream to write to ATMdata.txt
      out = new PrintWriter(datafile.getName());
      // Write the first three values of the two dimensional array
      // to the ATMdata.txt file. 
     out.format ("%s %s %s %s %s", account_inf[0][0], account_inf[0][1], account_inf[0][2], account_inf[0][3], account_inf[0][4]);
    } finally { 
      if (out != null) {  
        out.close();
      }
    }
  }   
    
  static void writeFile()throws IOException {
    PrintWriter out = null;
    try {
      // Create an output stream to write to ATMdata.txt
      out = new PrintWriter(datafile.getName());
      // Write account_inf[][] to disk 
      for (int i = 0; i<=lines-1; i++) {
        out.format ("%s %s %s %s %s", account_inf[i][0], 
                                account_inf[i][1], 
                                account_inf[i][2],
                                account_inf[i][3],
                                account_inf[i][4]);
                                
        out.println();
      }                         
    } finally { 
      if (out != null) {  
        out.close();
      }
    }
  }  
    
  static String getPin(String account_id){
    String pin = "";
    for (int i = 0; i <= lines ; i++) {
      if (account_id.equals(account_inf[i][2])) {
        pin = account_inf[i][3];
        lineNo = i;
        // Debug code
        System.out.println("pinString="+pin);
        break; 
      }
    }    
    
    return pin;    
  }
  
  static String getAccountname (String account_id){
    String accountname = account_inf[0][0];
    for (int i = 0; i <= lines ; i++) {
        if (account_id.equals(account_inf[i][2])) {
        accountname = account_inf[i][0];
        lineNo = i;
        // Debug code
        break; 
      }
    }
     return accountname;    
    }    
   
    static String getBankmanager_id (String account_id){
    String bankmanager_id = account_inf[2][2];
    for (int i = 0; i <= lines ; i++) {
        if (account_id.equals(account_inf[2][2])) {
        bankmanager_id = account_inf[2][3];
        lineNo = i;
        // Debug code
        break; 
      }
    }
     return bankmanager_id;    
    }    
    
  
  static String getTransferaccount_id(String account_id){
   String transferaccount_id = "";
    for (int i = 0; i <= lines ; i++) {
      if (account_id.equals(account_inf[i][2])) {
        transferaccount_id = account_inf[i][2];
        lineTo = i;
        // Debug code
         System.out.println("transferaccount_idString="+transferaccount_id);
        break; 
      }
    }    
    
    return transferaccount_id;    
  }
  
   static String getAccountbalance (String account_id){
    String accountbalance = account_inf[lineTo][4];
    for (int i = 0; i <= lines ; i++) {
        if (account_id.equals(account_inf[i][2])) {
        accountbalance = account_inf[i][4];
        lineTo = i;
        // Debug code
        break; 
      }
    }
     return accountbalance;    
    }    
    
   static String doDeposits(String amount){ 
    // Deposit cash -- called from ATMDeposits
    String newBalance = "";
    // Turn Strings to doubles for arithmatic
    double depositsAmount=                 
        (new Double(amount)).doubleValue();
    double currentBalance= 
        (new Double(account_inf[lineNo][4])).doubleValue(); 
    // Get the new balance as a string & update the account_inf array    
      newBalance = Double.toString
                    (currentBalance + depositsAmount);
      account_inf[lineNo][4] = newBalance;    
    
    return newBalance;    
  }
  
   
  static String doWithdrawl(String amount){ 
    // Withdraw cash -- called from ATMWithdrawl
    String newBalance = "";
    // Turn Strings to doubles for arithmatic
    double withdrawlAmount=                 
        (new Double(amount)).doubleValue();
    double currentBalance= 
        (new Double(account_inf[lineNo][4])).doubleValue(); 
    // Get the new balance as a string & update the account_inf array    
    if (withdrawlAmount <= currentBalance) { 
    newBalance = Double.toString
                    (currentBalance - withdrawlAmount);
      account_inf[lineNo][4] = newBalance;    
    }
    return newBalance;    
  }

 static String doTransfer(String amount){ 
    // Withdraw cash -- called from ATMWithdrawl
    String newBalance = "";
    String newBalance1 = "";
    // Turn Strings to doubles for arithmatic
    double transferAmount=                 
        (new Double(amount)).doubleValue();
    double currentBalance= 
        (new Double(account_inf[lineNo][4])).doubleValue(); 
    double currentBalance1= 
        (new Double(account_inf[lineTo][4])).doubleValue(); 
    // Get the new balance as a string & update the account_inf array    
    if (transferAmount <= currentBalance) {
    newBalance = Double.toString
                    (currentBalance - transferAmount);
      account_inf[lineNo][4] = newBalance;
    newBalance1 = Double.toString
                    (currentBalance1 + transferAmount);
      account_inf[lineTo][4] = newBalance1;
    }         
      return newBalance;
    }

 
 static String getBalance() {
    return account_inf[lineNo][4]; 
}

static String getAccountbalance() {
    return account_inf[lineTo][4]; 
}
}

[Paul Clapham]

Yes, the simple thing you missed was to tell us which of those 400 lines of code produced that error message. I wouldn't expect anybody to examine the whole lot carefully to figure that out, when you could just tell us.

[Brian O'Connor]

Sorry, found on line 88.

double currentBalance=
(new Double (atmData.getBalance())).doubleValue();
if (input <= currentBalance) {
au20Button.setEnabled(false);

[Maneesh Godbole]

Hint:
Can you compare apples and oranges? String and double? Windoze and Mac?

[Brian O'Connor]

Yeah, im only new to Java so i dont have alot of knowledge, but how do i go about rectifying this issue? do you convert the string or what?

[Maneesh Godbole]

Convert the String to double and then compare. Hint:Check out the Double constructor.

[Brian O'Connor]

So this compiles but it's not blanking out the buttons.

  double currentBalance= 
             (new Double (atmData.getBalance())).doubleValue(); 
            
             if ((20)<= currentBalance) {  
              au20Button.setEnabled(false);   
             if ((50)<= currentBalance) {  
              au50Button.setEnabled(false);
             if ((100)<= currentBalance) {  
              au100Button.setEnabled(false);   
             if ((200)<= currentBalance) {  
              au200Button.setEnabled(false);   
             if ((300)<= currentBalance) {  
              au300Button.setEnabled(false);   
        
            }
        }
        }
    }
}
}
}

[Maneesh Godbole]

So what's the value of currentBalance?

[Brian O'Connor]

$100 by default

[Maneesh Godbole]

I would suggest using

double currentBalance= (new Double (atmData.getBalance())).doubleValue(); 
System.out.println(currentBalance);

to check what actual value you are getting.

[Brian O'Connor]

Ok just tried that and it is working, when i withdraw $20 the console produces $80.

[Maneesh Godbole]

And the 20 and 50 buttons are getting disabled?

[Brian O'Connor]

Did you mean if they are disabling if the balance is under the withdraw amount? then still no =(

[Maneesh Godbole]

I think it would help if you post your SSCCE code, which we can download and run in our environment. Please do take out time to click on the SSCCE link to find out what it really means.

[Brian O'Connor]

Ok so you would like me to upload all of the classes and other information?

[Maneesh Godbole]

Maneesh Godbole wrote:Please do take out time to click on the SSCCE link to find out what it really means.

Did you do this?
http://sscce.org/