Using Factory and Singleton Design Patterns to Create a Simple Form

[Dan Pants]

Hi all! This question might be asking to much of the code ranch but I honestly do not know where to begin with this one.

My assignment was to create a simple form that demonstrates the use of the factory and singleton design patterns. "Use the Factory pattern to ensure that each form input consists of a text label and a textfield. Use the Singleton pattern for the submit button. When the submit button is clicked, a pop-up should show all the information that was typed into all of the form fields."

I used JFrame to create the form without the design patterns and I although I get the desired result, I'm not quite sure how I can integrate the design patterns into the code I wrote. The example I have to go off uses shapes, not text fields so I think that's why I'm not quite clear on how to approach this.

Any hints to get me started in the right direction would be much appreciated. Thank you!

Here's my code so far:

import javax.swing.event.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class JavaForm extends JFrame
{
   //full name
    private Panel nameChoicePanel;
    private TextField nameChoice;
    private Label nameLabel;

	//street address
    private Panel addressChoicePanel;
    private TextField addressChoice;
    private Label addressLabel;

	//city
    private Panel cityChoicePanel;
    private TextField cityChoice;
    private Label cityLabel;

	//state
    private Panel stateChoicePanel;
    private TextField stateChoice;
    private Label stateLabel;

    //zip
	private Panel zipChoicePanel;
	private TextField zipChoice;
    private Label zipLabel;

    //phone
	private Panel phoneChoicePanel;
	private TextField phoneChoice;
    private Label phoneLabel;

	//submit button
 	private Panel buttonPanel;
    private Button submitButton;



//Constructor
	   public JavaForm()
	   {

			        setTitle("FORM");
			        setSize(850,200);
			        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			        setLayout(new GridLayout(2, 1));

			        //Text fields
			        buildSelectedNamePanel();
			        buildSelectedAddressPanel();
			        buildSelectedCityPanel();
			        buildSelectedStatePanel();
			        buildSelectedZipPanel();
			        buildSelectedPhonePanel();
			        buildButtonPanel();

			        //Add to content pane.
			        add(nameChoicePanel);
			        add(addressChoicePanel);
			        add(cityChoicePanel);
			        add(stateChoicePanel);
			        add(zipChoicePanel);
			        add(phoneChoicePanel);
			        add(buttonPanel);
			}


    private void buildSelectedNamePanel()
      {
        //Create for text field
        nameChoicePanel = new Panel();
        nameLabel = new Label("Full Name: ");
        nameChoice = new TextField(15);
        nameChoicePanel.add(nameLabel);
        nameChoicePanel.add(nameChoice);
      }

    private void buildSelectedAddressPanel()
  	    {
         //Create for text field
        addressChoicePanel = new Panel();
        addressLabel = new Label("Street Address: ");
        addressChoice = new TextField(15);
        addressChoicePanel.add(addressLabel);
        addressChoicePanel.add(addressChoice);
   	    }


    private void buildSelectedCityPanel()
   	   {
        //Create a panel for text field.
        cityChoicePanel = new Panel();
        cityLabel = new Label("City: ");
        cityChoice = new TextField(12);
        cityChoicePanel.add(cityLabel);
        cityChoicePanel.add(cityChoice);
   		}

    private void buildSelectedStatePanel()
    	{
        //Create panel for text field
        stateChoicePanel = new Panel();
        stateLabel = new Label("State: ");
        stateChoice = new TextField(15);
        stateChoicePanel.add(stateLabel);
        stateChoicePanel.add(stateChoice);
    	}

        private void buildSelectedZipPanel()
  		 {
	        //Create panel for text field
	        zipChoicePanel = new Panel();
	        zipLabel = new Label("Zip Code: ");
	        zipChoice = new TextField(5);
	        zipChoicePanel.add(zipLabel);
	        zipChoicePanel.add(zipChoice);
  	  	 }

        private void buildSelectedPhonePanel()
	    {
	        //Create panel for text field
	        phoneChoicePanel = new Panel();
	        phoneLabel = new Label("Phone: ");
	        phoneChoice = new TextField(12);
	        phoneChoicePanel.add(phoneLabel);
	        phoneChoicePanel.add(phoneChoice);
   	    }


    private void buildButtonPanel()
    {
        //Create a submit button and add to panel
        buttonPanel = new Panel();
        submitButton = new Button("Submit");
        submitButton.addActionListener(new SubmitButtonListener());
        buttonPanel.add(submitButton);
    }


    public class SubmitButtonListener implements ActionListener
    {

        public void actionPerformed(ActionEvent e)
        {
			String name = nameChoice.getText();
			String address = addressChoice.getText();
			String city = cityChoice.getText();
			String state = stateChoice.getText();
			String zip = zipChoice.getText();
			String phone = phoneChoice.getText();

            JOptionPane.showMessageDialog(null, "Full Name: " + name + "\nStreet Address: " + address + "\nCity: " + city +
            							"\nState: " + state + "\nZip: " + zip + "\nPhone: " + phone);
        }
    }


public static void main(String[] args)
	{
		JavaForm form = new JavaForm();
		form.setVisible(true);
	}

}

[Winston Gutkowski]

Dan Pants wrote:Hi all! This question might be asking to much of the code ranch but I honestly do not know where to begin with this one.
My assignment was to create a simple form that demonstrates the use of the factory and singleton design patterns. "Use the Factory pattern to ensure that each form input consists of a text label and a textfield. Use the Singleton pattern for the submit button.

Hi Dan,

Not quite sure what you want here, and I also notice that the thread has been marked as "resolved", but here goes:

1. Do you know what the Factory and Singleton patterns are? Can you describe them?
2. Can you explain how they might be used in such an application? I have to admit being somewhat mystified as to why you might want to implement a submit Button as a Singleton; but I'm certainly no GUI expert, and I'm sure your tutors have their reasons.

So far, what I see is a fairly standard GUI program, so perhaps you could explain where you've tried to implement the patterns you've been asked to.

Winston

[Junilu Lacar]

Dan Pants wrote:This question might be asking to much of the code ranch but I honestly do not know where to begin with this one.

Unless you are asking us to find the cure to cancer, we like to think that very few things are too much to ask of the CodeRanch

When the submit button is clicked, a pop-up should show all the information that was typed into all of the form fields.

I don't want to confuse matters more for you but this doesn't exactly seem like a proper use of singleton to me.

[Campbell Ritchie]

A lot of people here think singleton is an anti‑pattern.

As Winston suggests, you would do well to write out what you know about factory and singleton. That will focus your thoughts and enable you to work things out for yourself. There is a name for that sort of programming. There is even a picture of it on Wikipedia.

[Dan Pants]

Hey all! Thanks for the replies. I marked this as resolved because I thought I'd give it another go on my own. I scrapped all the code I wrote and started from scratch, this time trying to closely follow factory design pattern template in my textbook.

These design patterns are basically "best practices" and by learning these patterns, inexperienced programmers such as myself can learn software design more easily. I know the Factory design pattern is an ideal way to create objects in java. It uses a common interface to create its new objects. The singleton pattern is an ideal way to create a single object and to ensure only one instance of that single object is created.

@ Junilu After re-reading my question, it looked like I was asking you all "Here's my code, now re-write it for me this way." That's what i meant by asking too much, so I marked it resolved and tried it on my own. I think the way it was explained to me (using shapes instead of text fields and demonstrated in Greenfoot (a java learning environment) and not in an IDE) I was a bit intimidated about getting started so I just wrote the program the way I knew how.

@ Winston & Junilu I admit, the more I read, it seems like Singleton submit button is not the way to go, but this is what I was asked for. However, my mention that "When the submit button is clicked, a pop-up should show all the information that was typed into all of the form fields." was not part of the assignment, just something I thought would be helpful for me for testing purposes.

Still working on the singleton submit button but here's what I have so far:

Form.java file

interface Form
{
  public void getFormField ();
}

Name.java file (I have a similar files just like this for Address.java, City.java, State.java, Zip.java and Phone.java)

import java.util.Scanner;

class Name implements Form
{
  public void getFormField()
  {
	Scanner scanner = new Scanner( System.in );
    System.out.println("What is your full name:");
    String name = scanner.nextLine();
    System.out.println(name );
  }
}

FormFactory.java file

class FormFactory
{
  public static Form getForm(String choice)
  {
    if ( choice.equals("NAME") )
      return new Name();
    else if ( choice.equals("ADDRESS") )
      return new Address();
    else if ( choice.equals("CITY") )
      return new City();
    else if ( choice.equals("STATE") )
      return new State();
    else if ( choice.equals("ZIP") )
      return new Zip();
    else if ( choice.equals("PHONE") )
      return new Phone();

    return null;
  }
}

FormFactoryDemo.java file

public class FormFactoryDemo
{
  public static void main(String[] args)
  {
    // create name field
    Form name = FormFactory.getForm("name");
    name.getFormField();

    // create address field
    Form address = FormFactory.getForm("address");
    address.getFormField();

    // create city field
    Form city = FormFactory.getForm("city");
    city.getFormField();

	// create state field
	Form state = FormFactory.getForm("state");
    state.getFormField();

    //create zip field
	Form zip = FormFactory.getForm("zip");
    zip.getFormField();

    //create phone field
	Form phone = FormFactory.getForm("phone");
    phone.getFormField();
  }
}

As I said I am still working on it, but because you guys were nice enough to respond I thought I'd post what I have presently. It compiles at the moment but I get a null pointer exception in the main method of the FormFactoryDemo file. Need to add that singleton design pattern submit button ASAP so I can work through this.

Can you tell me if I am on the right track at least?? Thanks to all for your input and advice it was extremely helpful!