Question

I am going to write a library aplication program.

I work with netbeans.

i have an interface like this:

package Library;

 public interface UserInformation {

 public void setFName(String fn);
 public String getFName();
 public void setLName(String ln);
 public String getLName();
 public void setRegNum(int reg_num);
 public int getRegNum();
 public void setDate(int reg_date);
 public int getDate();
}

and my NewUserDialog implements this interface:

private String FirstName="";
private String LastName="";
private int Registration_Number=0;
private int Date=0;
private String fileadress="AllUserRecords.txt";

public NewUserDialog(java.awt.Frame parent, boolean modal) {
    super(parent, modal);
    initComponents();

}
// // <editor-fold defaultstate="collapsed" desc="Generated Code">

private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();
    jLabel3 = new javax.swing.JLabel();
    jLabel4 = new javax.swing.JLabel();
    jTextField1 = new javax.swing.JTextField();
    jTextField2 = new javax.swing.JTextField();
    jTextField3 = new javax.swing.JTextField();
    jButton1 = new javax.swing.JButton();
    jButton2 = new javax.swing.JButton();
    jLabel5 = new javax.swing.JLabel();
    jLabel6 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);

    jLabel1.setFont(new java.awt.Font("Tunga", 1, 14)); // NOI18N
    jLabel1.setText("Add New User (Registration)");

    jLabel2.setText("First Name:");

    jLabel3.setText("Last Name:");

    jLabel4.setText("Date:");

    jTextField2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jTextField2ActionPerformed(evt);
        }
    });

jButton1.setText("Create");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jButton2.setText("Back");

    jLabel5.setText("Registration Number is:");

    jLabel6.setText("            ");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(54, 54, 54)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(jLabel2)
                        .addComponent(jLabel4)
                        .addComponent(jLabel3)
                        .addComponent(jLabel5))
                    .addGap(98, 98, 98)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(jLabel6)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(jTextField3)
                            .addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 81, Short.MAX_VALUE)
                            .addComponent(jButton2, javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jTextField2))
                        .addComponent(jLabel1)))
                .addGroup(layout.createSequentialGroup()
                    .addGap(68, 68, 68)
                    .addComponent(jButton1)))
            .addContainerGap(141, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addGap(26, 26, 26)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jLabel2)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(28, 28, 28)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(jLabel3))
                    .addGap(34, 34, 34)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(jLabel4))))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 50, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel5)
                .addComponent(jLabel6))
            .addGap(27, 27, 27)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1)
                .addComponent(jButton2))
            .addGap(116, 116, 116))
    );

    pack();
}// </editor-fold>                        

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    try{
    setFName(jTextField1.getText());
    if(havedigit(FirstName)==true) throw new Exception();
    WriteToFile(getFName());
    setLName(jTextField2.getText());
    if(havedigit(LastName)==true) throw new Exception();
    WriteToFile(getLName());
    setDate(Integer.parseInt(jTextField3.getText()));
    WriteToFile(String.valueOf(getDate()));
    Random rnd1=new Random();
    Registration_Number=rnd1.nextInt(100);
    setRegNum(Registration_Number);
    WriteToFile(String.valueOf(getRegNum()));
    jLabel6.setText(String.valueOf(getRegNum()));
    }
    catch(Exception e){
        jLabel6.setText("Error!");
    }
}                                        

public boolean havedigit(String in){
    for(int i=0;i<in.length();i++){
        if(Character.isDigit(in.charAt(i)))  return true;
    }
    return false;
}

public void WriteToFile(String content){
    try{
        File f=new File("C:\\userrecords.txt");
        if(!f.exists()){
            f.createNewFile();
        }
        else{
            FileWriter fw=new FileWriter(f.getAbsoluteFile(), true);
            BufferedWriter bw=new BufferedWriter(fw);
            bw.write(content);
            bw.newLine();
            bw.close();
            System.out.println("Done");
        }
    }
    catch(Exception e){
        e.printStackTrace();
    }

}

public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            NewUserDialog dialog = new NewUserDialog(new javax.swing.JFrame(), true);
            dialog.addWindowListener(new java.awt.event.WindowAdapter() {
                public void windowClosing(java.awt.event.WindowEvent e) {
                    System.exit(0);
                }
            });
            dialog.setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JLabel jLabel6;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
private javax.swing.JTextField jTextField3;
// End of variables declaration                   

public void setFName(String fn) {
    FirstName.equals(fn);
}

public String getFName() {
    return FirstName;
}

public void setLName(String ln) {
    LastName.equals(ln);
}

public String getLName() {
    return FirstName;
}

public void setRegNum(int reg_num) {
    Registration_Number=reg_num;
}

public int getRegNum() {
    return Registration_Number;
}

public void setDate(int reg_date) {
    Date=reg_date;
}

 public int getDate() {
   return Date;
}
}

my purpose is that when we file the jtextfile fields and clicked the button, this data should save into a .txt file .
but both Fname and Lname did not save to file, just the “Date” file save to file.
and i want that Fname and Lname and Data must store regular in text file.

thanks!

Answer 1

Your setter methods, setFName(...) and setLName(...) don’t do any setting at all. Instead all they do is perform an unnecessary and inexplicable test of equality and then discard the result:

public void setLName(String ln) {
    LastName.equals(ln); // ???????
}

How about instead creating true setter methods that set the object held by a reference variable:

public void setLName(String ln) {
    lastName = ln; // note variable names should begin w/ a lowercase letter
}

If you don’t set these fields, then you can’t expect the information from the getter methods to be useful when writing to file.

Also you have a weak catch block that does not inform you of the contents of the stack trace, information that may help you figure out what is wrong.

Also, what purpose is there for your GUI to implement a non-GUI interface that seems better suited for a model class, not a view (GUI) class? I would favor composition here instead of inheritance.