Thread: Insert code that adds the String representation of the selected item to the ArrayList billItems.

I am not sure how to go about doing this, An ItemEvent.Selected constant is the hint given to me but i dont know how to start it.

my Array is:
private ArrayList billItems = new ArrayList();

my method is:

private void beverageJComboBoxItemStateChanged( ItemEvent event )

HELP!!!

Yeah well i did try this

{

String item = (String)event.getItem();
if (event.getStateChange() == ItemEvent.SELECTED)
{
billItems.append(item + " was selected\n");
}
else
{
billItems.append(item + " was deselected\n");
}
}
What i need to do is this:

Create the beverageJComboBoxItemStateChanged method (which immediately follows loadCategory) and insert code that adds the String representation of the selected item to the ArrayList billItems. [Hint: Use the ItemEvent.SELECTED constant to determine whether an item is selected.]

I haven't a clue how to go about it properly

I am sending you the entire code i have written so far

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.awt.Container;
import javax.swing.BorderFactory;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.ResultSetMetaData;
import java.sql.ResultSet;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
 
 
 
 
 
public class RestaurantBillCalculator extends JFrame
{
   static final String DATABASE_URL = "jdbc:mysql://localhost/restaurant";
   static final String DATABASE_USERNAME = "root";
   static final String DATABASE_PASSWORD = "password"; 
 
   // JLabel for Restaurant
   private JLabel restaurantJLabel;
 
   // JPanel to display waiter information
   private JPanel waiterJPanel;
 
   // JLabel and JTextField for table number
   private JLabel tableNumberJLabel;
   private JTextField tableNumberJTextField;
 
   // JLabel and JTextField for waiter name
   private JLabel waiterNameJLabel;
   private JTextField waiterNameJTextField;
 
   // JPanel to display menu items
   private JPanel menuItemsJPanel;
 
   // JLabel and JComboBox for beverage
   private JLabel beverageJLabel;
   private JComboBox beverageJComboBox;
 
   // JLabel and JComboBox for appetizer
   private JLabel appetizerJLabel;
   private JComboBox appetizerJComboBox;
 
   // JLabel and JComboBox for main course
   private JLabel mainCourseJLabel;
   private JComboBox mainCourseJComboBox;
 
   // JLabel and JComboBox for dessert
   private JLabel dessertJLabel;
   private JComboBox dessertJComboBox;
 
   // JButton for calculate bill
   private JButton calculateBillJButton;
 
   // JLabel and JTextField for subtotal
   private JLabel subtotalJLabel;
   private JTextField subtotalJTextField;
 
   // JLabel and JTextField for tax
   private JLabel taxJLabel;
   private JTextField taxJTextField;
 
   // JLabel and JTextField for total
   private JLabel totalJLabel;
   private JTextField totalJTextField;
 
   // constant for tax rate
   private final static double TAX_RATE = 0.05;
 
   // declare instance variables for database processing
   private Connection myConnection;
   private Statement myStatement;
   private ResultSet myResultSet;
 
   // declare instance variable ArrayList to hold bill items
   private ArrayList billItems = new ArrayList();
 
   // constructor
   public RestaurantBillCalculator( String databaseUserName, String databasePassword )
   {
     try 
     {
         myConnection = DriverManager.getConnection
        (DATABASE_URL, DATABASE_USERNAME, DATABASE_PASSWORD);
 
         myStatement = myConnection.createStatement();
 
         myResultSet = myStatement.executeQuery(DATABASE_URL);
     }
     catch ( SQLException sqlException )
      {
         sqlException.printStackTrace();
         System.exit( 1 );
      } // end catch
     finally
     {
         try
         {
             myResultSet.close();
             myStatement.close();
             myConnection.close();
         } // end of try block
 
         catch ( SQLException SQLexception )
         {
            SQLexception.printStackTrace();
         } // end catch block
     } // end of finally
 
   } // end constructor
 
   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();
 
      // enable explicit positioning of GUI components 
      contentPane.setLayout( null );
 
      // **** TODO ****** set up restaurantJLabel
      JLabel restaurantJLabel = new JLabel("Restaurant");
      restaurantJLabel.setFont(new Font("Times New Roman", Font.BOLD, 14));
      restaurantJLabel.setBounds(30, 50, 100, 100);
 
      JPanel waiterJPanel = new JPanel();
      waiterJPanel.setLayout(null);
      waiterJPanel.setBounds(20, 50, 100, 100);
      waiterJPanel.setBorder(BorderFactory.createTitledBorder
      (BorderFactory.createEtchedBorder(),"Waiter Information"));
 
      JPanel menuItemsJPanel = new JPanel();
      menuItemsJPanel.setLayout(null);
      menuItemsJPanel.setBounds(20, 50, 200, 200);
      waiterJPanel.setBorder(BorderFactory.createTitledBorder
     (BorderFactory.createEtchedBorder(),"Menu Items"));
 
      setLayout(null);
      JButton calculateBillJButton = new JButton("Calculate Button");
      calculateBillJButton.setBounds(250, 250, 50, 50);
 
//     public void actionPerformed( ActionEvent event)
//     {
//        calculateBillJButtonActionPerformed( event );
//     } 
// 
 
      JLabel subtotalJLabel = new JLabel("Sub Total");
      JTextField subtotalJTextField = new JTextField();
 
 
      JLabel totalJLabel = new JLabel("Total");
      JTextField totalJTextField = new JTextField();
 
      // **** TODO ****** set properties of application's window
 
      // **** TODO ****** ensure database connection is closed
      // **** TODO ****** when user quits application
      addWindowListener(
 
         new WindowAdapter()anonymous inner class
         {
            //  event handler called when close button is clicked
            public void windowClosing( WindowEvent event )
            {
               frameWindowClosing( event );
            }
 
         } //  end anonymous inner class
 
      ); // end addWindowListener
 
   } // end method createUserInterface
 
   // **** TODO ****** set up waiterJPanel
   private void createWaiterJPanel()
   {
      // **** TODO ****** set up waiterJPanel
 
 
      // **** TODO ****** set up tableNumberJLabel
 
      // **** TODO ****** set up tableNumberJTextField
 
      // **** TODO ****** set up waiterNameJLabel
 
      // **** TODO ****** set up waiterNameJTextField
 
   } // end method createWaiterJPanel
 
   // **** TODO ****** create menuItemsJPanel
   private void createMenuItemsJPanel()
   {
      //  set up menuItemsJPanel
      menuItemsJPanel = new JPanel();
      menuItemsJPanel.setBounds( 20, 152, 232, 152 );
      menuItemsJPanel.setBorder( BorderFactory.createTitledBorder( 
         BorderFactory.createEtchedBorder(), "Menu Items" ) );
      menuItemsJPanel.setLayout( null );
 
      //  set up beverageJLabel
      beverageJLabel = new JLabel();
      beverageJLabel.setBounds( 8, 24, 80, 24 );
      beverageJLabel.setText( "Beverage:" );
      menuItemsJPanel.add( beverageJLabel );
 
      // set up beverageJComboBox
      beverageJComboBox = new JComboBox();
      beverageJComboBox.setBounds( 88, 24, 128, 25 );
      menuItemsJPanel.add( beverageJComboBox );
      beverageJComboBox.addItemListener(
 
         new ItemListener()  // **** TODO ****** anonymous inner class
         {
            // **** TODO ****** event handler called when item in beverageJComboBox
            // **** TODO ****** is selected
            public void itemStateChanged( ItemEvent event )
            {
               beverageJComboBoxItemStateChanged( event );
            }
 
         } // end anonymous inner class
 
      ); // end addItemListener
 
      // **** TODO ****** add items to beverageJComboBox
 
 
      // **** TODO ****** set up appetizerJLabel
 
 
      // **** TODO ****** set up appetizerJComboBox
 
      // **** TODO ****** add items to appetizerJComboBox
 
 
      // **** TODO ****** set up mainCourseJLabel
 
      // **** TODO ****** set up mainCourseJComboBox
      mainCourseJComboBox = new JComboBox();
 
      // **** TODO ****** add items to mainCourseJComboBox
 
 
      // **** TODO ****** set up dessertJLabel
 
 
   } // end method createMenuItemsJPanel
 
   // **** TODO ****** add items to JComboBox
   private void loadCategory(
      String category, JComboBox categoryJComboBox )
   {
      loadCategory("beverage", beverageJComboBox);
      loadCategory("appetizer", appetizerJComboBox);
      loadCategory("main course", mainCourseJComboBox);
      loadCategory("dessert", dessertJComboBox);
 
      try
      {
         myResultSet = myStatement.executeQuery("SELECT name FROM" + 
         "Menu WHERE category = "" + category + ");
 
         while(myResultSet.next())
         {
             categoryJComboBox.addItem(myResultSet.getString("name"));
         }
         myResultSet.close();
      } // end try block
      catch ( SQLException SQLexception )
        {
            SQLexception.printStackTrace();
        } // end catch block         
 
   } // end method loadCategory
 
   // **** TODO ****** user select beverage
   private void beverageJComboBoxItemStateChanged( ItemEvent event )
   {
    ObJect obj = event.getSource();
    if(event.getStateChange()) == ItemEvent.SELECTED)
    {
 
    }
 
 
   } // end method beverageJComboBoxItemStateChanged
 
   // **** TODO ****** user select appetizer
   private void appetizerJComboBoxItemStateChanged( ItemEvent event )
   {
 
   } // end method appetizerJComboBoxItemStateChanged
 
   // **** TODO ****** user select main course
   private void mainCourseJComboBoxItemStateChanged( 
      ItemEvent event )
   {
 
   } // end method mainCourseJComboBoxItemStateChanged
 
   // **** TODO ****** user select dessert
   private void dessertJComboBoxItemStateChanged( ItemEvent event )
   {
 
   } // end method dessertJComboBoxItemStateChanged
 
   // **** TODO ****** user click Calculate Bill JButton
   private void calculateBillJButtonActionPerformed( 
      ActionEvent event )
   {
 
   } // end method calculateBillJButtonActionPerformed
 
   // **** TODO ****** calculate subtotal
   private double calculateSubtotal()
   {
      return 0;
 
   } // end method calculateSubtotal
 
   // **** TODO ****** user close window
   private void frameWindowClosing( WindowEvent event )
   {
 
   }  // end method frameWindowClosing
 
   // **** TODO ****** method main
   public static void main( String[] args ) 
   {
     JFrame createUserInterface = new JFrame();
     createUserInterface.setSize(500, 500);
     createUserInterface.setVisible(true);
     createUserInterface.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
     createUserInterface.setLocationRelativeTo(null);
 
 
      // **** TODO ****** check command-line arguments
      if ( args.length == 2 )
      {
         // **** TODO ****** get command-line arguments
         String databaseUserName = args[ 0 ];
         String databasePassword = args[ 1 ];
 
         // **** TODO ****** create new RestaurantBillCalculator
         RestaurantBillCalculator application = new RestaurantBillCalculator ( 
         databaseUserName, databasePassword );
 
 
      }
      else
      {
         System.out.println( "Usage: java " + 
            "RestaurantBillCalculator databaseUserName databasePassword" );
      }
 
   } // end method main
 
} // end class RestaurantBillCalculator

--- Update ---

The code doesnt compile fully yet as i am going step by step.

--- Update ---

Just going to send it one more time, the area I am having trouble with contained code that started with Object, that was me messing around for a solution, i have deleted those lines

// Project: RestaurantBillCalculator.java Calculates a table's bill.
 
// Import statements for different classes
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.awt.Container;
import javax.swing.BorderFactory;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.ResultSetMetaData;
import java.sql.ResultSet;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
 
 
 
 
 
public class RestaurantBillCalculator extends JFrame
{
   static final String DATABASE_URL = "jdbc:mysql://localhost/restaurant";
   static final String DATABASE_USERNAME = "root";
   static final String DATABASE_PASSWORD = "password"; 
 
   // JLabel for Restaurant
   private JLabel restaurantJLabel;
 
   // JPanel to display waiter information
   private JPanel waiterJPanel;
 
   // JLabel and JTextField for table number
   private JLabel tableNumberJLabel;
   private JTextField tableNumberJTextField;
 
   // JLabel and JTextField for waiter name
   private JLabel waiterNameJLabel;
   private JTextField waiterNameJTextField;
 
   // JPanel to display menu items
   private JPanel menuItemsJPanel;
 
   // JLabel and JComboBox for beverage
   private JLabel beverageJLabel;
   private JComboBox beverageJComboBox;
 
   // JLabel and JComboBox for appetizer
   private JLabel appetizerJLabel;
   private JComboBox appetizerJComboBox;
 
   // JLabel and JComboBox for main course
   private JLabel mainCourseJLabel;
   private JComboBox mainCourseJComboBox;
 
   // JLabel and JComboBox for dessert
   private JLabel dessertJLabel;
   private JComboBox dessertJComboBox;
 
   // JButton for calculate bill
   private JButton calculateBillJButton;
 
   // JLabel and JTextField for subtotal
   private JLabel subtotalJLabel;
   private JTextField subtotalJTextField;
 
   // JLabel and JTextField for tax
   private JLabel taxJLabel;
   private JTextField taxJTextField;
 
   // JLabel and JTextField for total
   private JLabel totalJLabel;
   private JTextField totalJTextField;
 
   // constant for tax rate
   private final static double TAX_RATE = 0.05;
 
   // declare instance variables for database processing
   private Connection myConnection;
   private Statement myStatement;
   private ResultSet myResultSet;
 
   // declare instance variable ArrayList to hold bill items
   private ArrayList billItems = new ArrayList();
 
   // constructor
   public RestaurantBillCalculator( String databaseUserName, String databasePassword )
   {
     try 
     {
         myConnection = DriverManager.getConnection
        (DATABASE_URL, DATABASE_USERNAME, DATABASE_PASSWORD);
 
         myStatement = myConnection.createStatement();
 
         myResultSet = myStatement.executeQuery(DATABASE_URL);
     }
     catch ( SQLException sqlException )
      {
         sqlException.printStackTrace();
         System.exit( 1 );
      } // end catch
     finally
     {
         try
         {
             myResultSet.close();
             myStatement.close();
             myConnection.close();
         } // end of try block
 
         catch ( SQLException SQLexception )
         {
            SQLexception.printStackTrace();
         } // end catch block
     } // end of finally
 
   } // end constructor
 
   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();
 
      // enable explicit positioning of GUI components 
      contentPane.setLayout( null );
 
      // **** TODO ****** set up restaurantJLabel
      JLabel restaurantJLabel = new JLabel("Restaurant");
      restaurantJLabel.setFont(new Font("Times New Roman", Font.BOLD, 14));
      restaurantJLabel.setBounds(30, 50, 100, 100);
 
      JPanel waiterJPanel = new JPanel();
      waiterJPanel.setLayout(null);
      waiterJPanel.setBounds(20, 50, 100, 100);
      waiterJPanel.setBorder(BorderFactory.createTitledBorder
      (BorderFactory.createEtchedBorder(),"Waiter Information"));
 
      JPanel menuItemsJPanel = new JPanel();
      menuItemsJPanel.setLayout(null);
      menuItemsJPanel.setBounds(20, 50, 200, 200);
      waiterJPanel.setBorder(BorderFactory.createTitledBorder
     (BorderFactory.createEtchedBorder(),"Menu Items"));
 
      setLayout(null);
      JButton calculateBillJButton = new JButton("Calculate Button");
      calculateBillJButton.setBounds(250, 250, 50, 50);
 
//     public void actionPerformed( ActionEvent event)
//     {
//        calculateBillJButtonActionPerformed( event );
//     } 
// 
 
      JLabel subtotalJLabel = new JLabel("Sub Total");
      JTextField subtotalJTextField = new JTextField();
 
 
      JLabel totalJLabel = new JLabel("Total");
      JTextField totalJTextField = new JTextField();
 
      // **** TODO ****** set properties of application's window
 
      // **** TODO ****** ensure database connection is closed
      // **** TODO ****** when user quits application
      addWindowListener(
 
         new WindowAdapter()anonymous inner class
         {
            //  event handler called when close button is clicked
            public void windowClosing( WindowEvent event )
            {
               frameWindowClosing( event );
            }
 
         } //  end anonymous inner class
 
      ); // end addWindowListener
 
   } // end method createUserInterface
 
   // **** TODO ****** set up waiterJPanel
   private void createWaiterJPanel()
   {
      // **** TODO ****** set up waiterJPanel
 
 
      // **** TODO ****** set up tableNumberJLabel
 
      // **** TODO ****** set up tableNumberJTextField
 
      // **** TODO ****** set up waiterNameJLabel
 
      // **** TODO ****** set up waiterNameJTextField
 
   } // end method createWaiterJPanel
 
   // **** TODO ****** create menuItemsJPanel
   private void createMenuItemsJPanel()
   {
      //  set up menuItemsJPanel
      menuItemsJPanel = new JPanel();
      menuItemsJPanel.setBounds( 20, 152, 232, 152 );
      menuItemsJPanel.setBorder( BorderFactory.createTitledBorder( 
         BorderFactory.createEtchedBorder(), "Menu Items" ) );
      menuItemsJPanel.setLayout( null );
 
      //  set up beverageJLabel
      beverageJLabel = new JLabel();
      beverageJLabel.setBounds( 8, 24, 80, 24 );
      beverageJLabel.setText( "Beverage:" );
      menuItemsJPanel.add( beverageJLabel );
 
      // set up beverageJComboBox
      beverageJComboBox = new JComboBox();
      beverageJComboBox.setBounds( 88, 24, 128, 25 );
      menuItemsJPanel.add( beverageJComboBox );
      beverageJComboBox.addItemListener(
 
         new ItemListener()  // **** TODO ****** anonymous inner class
         {
            // **** TODO ****** event handler called when item in beverageJComboBox
            // **** TODO ****** is selected
            public void itemStateChanged( ItemEvent event )
            {
               beverageJComboBoxItemStateChanged( event );
            }
 
         } // end anonymous inner class
 
      ); // end addItemListener
 
      // **** TODO ****** add items to beverageJComboBox
 
 
      // **** TODO ****** set up appetizerJLabel
 
 
      // **** TODO ****** set up appetizerJComboBox
 
      // **** TODO ****** add items to appetizerJComboBox
 
 
      // **** TODO ****** set up mainCourseJLabel
 
      // **** TODO ****** set up mainCourseJComboBox
      mainCourseJComboBox = new JComboBox();
 
      // **** TODO ****** add items to mainCourseJComboBox
 
 
      // **** TODO ****** set up dessertJLabel
 
 
   } // end method createMenuItemsJPanel
 
   // **** TODO ****** add items to JComboBox
   private void loadCategory(
      String category, JComboBox categoryJComboBox )
   {
      loadCategory("beverage", beverageJComboBox);
      loadCategory("appetizer", appetizerJComboBox);
      loadCategory("main course", mainCourseJComboBox);
      loadCategory("dessert", dessertJComboBox);
 
      try
      {
         myResultSet = myStatement.executeQuery("SELECT name FROM" + 
         "Menu WHERE category = "" + category + ");
 
         while(myResultSet.next())
         {
             categoryJComboBox.addItem(myResultSet.getString("name"));
         }
         myResultSet.close();
      } // end try block
      catch ( SQLException SQLexception )
        {
            SQLexception.printStackTrace();
        } // end catch block         
 
   } // end method loadCategory
 
   // **** TODO ****** user select beverage
   private void beverageJComboBoxItemStateChanged( ItemEvent event )
   {
 
 
 
   } // end method beverageJComboBoxItemStateChanged
 
   // **** TODO ****** user select appetizer
   private void appetizerJComboBoxItemStateChanged( ItemEvent event )
   {
 
   } // end method appetizerJComboBoxItemStateChanged
 
   // **** TODO ****** user select main course
   private void mainCourseJComboBoxItemStateChanged( 
      ItemEvent event )
   {
 
   } // end method mainCourseJComboBoxItemStateChanged
 
   // **** TODO ****** user select dessert
   private void dessertJComboBoxItemStateChanged( ItemEvent event )
   {
 
   } // end method dessertJComboBoxItemStateChanged
 
   // **** TODO ****** user click Calculate Bill JButton
   private void calculateBillJButtonActionPerformed( 
      ActionEvent event )
   {
 
   } // end method calculateBillJButtonActionPerformed
 
   // **** TODO ****** calculate subtotal
   private double calculateSubtotal()
   {
      return 0;
 
   } // end method calculateSubtotal
 
   // **** TODO ****** user close window
   private void frameWindowClosing( WindowEvent event )
   {
 
   }  // end method frameWindowClosing
 
   // **** TODO ****** method main
   public static void main( String[] args ) 
   {
     JFrame createUserInterface = new JFrame();
     createUserInterface.setSize(500, 500);
     createUserInterface.setVisible(true);
     createUserInterface.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
     createUserInterface.setLocationRelativeTo(null);
 
 
      // **** TODO ****** check command-line arguments
      if ( args.length == 2 )
      {
         // **** TODO ****** get command-line arguments
         String databaseUserName = args[ 0 ];
         String databasePassword = args[ 1 ];
 
         // **** TODO ****** create new RestaurantBillCalculator
         RestaurantBillCalculator application = new RestaurantBillCalculator ( 
         databaseUserName, databasePassword );
 
 
      }
      else
      {
         System.out.println( "Usage: java " + 
            "RestaurantBillCalculator databaseUserName databasePassword" );
      }
 
   } // end method main
 
} // end class RestaurantBillCalculator

No because this is all one, would you like the SQL stuff?

--- Update ---

Im only looking how to write the code, I'm not worried about the SQL stuff, i know i have to use the ItemEvent.SELECTED to get it to work, just not sure how to start it.

reminder:

// below is the method
private void beverageJComboBoxItemStateChanged( ItemEvent event )
{
}
 
// below is the instance variable of ArrayList BillItems
private ArrayList billItems = new ArrayList();

This is the only method, the question i want answered is how do i do an itemEvent.selected inside this method??

Okay if you want a small program, i'll try one, not sure if this will work though

import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
 
 
public class RestaurantBillCalculator extends JFrame
{
private JComboBox beverageJComboBox;
 
private ArrayList billItems = new ArrayList();
 
private void beverageJComboBoxItemStateChanged( ItemEvent event )
{// code for the ItemEvent.selected goes here i believe, im am stuck with this in the sense of how to do it}
 
 
 
public static void main(String... Args)
{
  JFrame createUserInterface = new JFrame();
     createUserInterface.setSize(500, 500);
     createUserInterface.setVisible(true);
     createUserInterface.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
     createUserInterface.setLocationRelativeTo(null);
 
}
 
 
}

That's what i am asking for, how do i do the LISTENER inside that method? all i want is an example of how to do the ItemEvent.selected within beverageJComboBoxItemStateCHanged method. I am not not worried about it compiling just yet.
e.g would it go like something below???

private void beverageJComboBoxItemStateChanged( ItemEvent event )
  {              
String item = (String)e.getItem();
                if (e.getStateChange() == ItemEvent.SELECTED)
                {
                    feedback.append(item + " was selected\n");
                }
                else
                {
                    feedback.append(item + " was deselected\n");
                }
            }

I am a java beginner so don't go into series hardcore detail. All i want is to KNOW HOW to do an ItemEvent.Selected from the code above, that's all

First of all, you dont "do an ItemEvent.Selected". There is no such thing.
What exists is ItemEvent.SELECTED. This is a public static final integer variable that is part of the ItemEvent class. You need to use this variable at some point in your program and what you have so far is already using it correctly.

Try to use this code first:

private void beverageJComboBoxItemStateChanged( ItemEvent event )
  {              
                if (e.getStateChange() == ItemEvent.SELECTED)
                {
                    System.out.println("selected something");
                }
                else
                {
                    System.out.println("unselected something");
                }
            }

which is almost what you have got, but slightly changed. What this will do is print a message to the console when the selection of the combo box is changed.
It will show you when something was selected or unselected.

Once you have got this working you have to find out how to get the item that was selected.
When you managed to do that, you have to find out how to get a textual representation for that item.

Perhaps you read the API for ItemEvent, JComboBox and whatever class you use for your Items.

I aware ItemEvent.selected does not exist, i should have spelt it correctly sorry and also thanks, ill give it a go.

After messing around with it a lot i finally got it working, its fairly similar to what you said except i need it to be associated with the ArrayList billItems

code is:

private void beverageJComboBoxItemStateChanged( ItemEvent event )
  {              
       if (e.getStateChange() == ItemEvent.SELECTED)
         {
            billItems.add((String)beverageJComboBox.getSelecteditem());
         }
} // end of beverageJComboBoxItemStateChanged

I don't need the ELSE because i am only concerned with selecting an Item not deselecting!