get window state with multiple frames

Hello again... ;-)

Can someone point me to a good tutorial on using multiple JFrames in a Java app?

I am trying to write an app that opens multiple JFrames (depending on which button the user clicks from the main JFrame). So far everything works just fine, however, I want to prevent users from being able to open multiple instances of the same frame. Right now its not a bother, as the frames don't do anything, but eventually, this will access a database, and I dont want a user to be able to open 100 different frames accessing the same database...

I have looked at various listeners, and have implemented a few of them, but the problem I am having is determining WHAT frame is sending the action. doing an event.getSource() in the windowEvent handler gives me something like this:

myproject.formCheckAvailability[lots of configuration stuff here]

I set a name for each form using form.setName(), but I cant seem to pull that out.

Here is what I have so far. Please ignore most of it as it does not really do anything yet, and I just started on it this evening:

Code:

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package airvendettaseatingsystem;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.awt.*;
public class mainForm extends javax.swing.JFrame implements java.awt.event.ActionListener, java.awt.event.WindowListener {
    public int checkState = 0;
    public int viewState = 0;
    public int reserveState = 0;
    public int cancelState = 0;
    frmCheck newCheck;
 frmView newView;

    /** Creates new form mainForm */
    public mainForm() {
        initComponents();
    }

    public void windowActivated(WindowEvent es) {
        System.out.println("Activated "+es.getSource());
        System.out.println(es.getID());
        System.out.println(es.getComponent());
    }
    public void windowDeactivated(WindowEvent eh) {
        System.out.println("Deactivated "+eh.getSource());
        System.out.println(eh.getID());
        System.out.println(eh.getComponent());
    }
    public void windowIconified(WindowEvent em) {
        System.out.println("Iconified "+em.getSource());
    }
    public void windowDeiconified(WindowEvent er) {
        System.out.println("Deiconified "+er.getSource());
    }
    public void windowClosed(WindowEvent wc) {
        System.out.println(wc.getSource());
    }
    public void windowClosing(WindowEvent wi) {
        System.out.println(wi.getSource());
    }
      public void windowOpened(WindowEvent wo) {
          if (wo.getSource() == newView)
              System.out.println("GOTCHA");
    }

    public void actionPerformed(ActionEvent event){
        System.out.println(event.getSource());
        if (event.getSource() == btnCheck){
//            if (checkState == 0){
            System.out.println("Check Button");
            frmCheck newCheck = new frmCheck();
            newCheck.setName("myCheck");
            newCheck.addWindowListener(this);
            newCheck.setLocationRelativeTo(this);
            newCheck.setVisible(true);
            checkState = 1;
//            }
        }
        if (event.getSource() == btnView){
            System.out.println("View Button");
            frmView newView = new frmView();
            newView.addWindowListener(this);
            newView.setVisible(true);}
        if (event.getSource() == btnReserve)
            System.out.println("Reserve Button");
        if (event.getSource() == btnCancel)
            System.out.println("Cancel Button");
        if (event.getSource() == btnExit)
            dispose();
    }
    /** This method is called from within the constructor to
    * initialize the form.
    * WARNING: Do NOT modify this code. The content of this method is
    * always regenerated by the Form Editor.
    */
    private void initComponents() {//GEN-BEGIN:initComponents
        pnlMain = new javax.swing.JPanel();
        btnCheck = new javax.swing.JButton();
        lblCheck = new javax.swing.JLabel();
      lblView = new javax.swing.JLabel();
        btnView = new javax.swing.JButton();
        btnReserve = new javax.swing.JButton();
        lblReserve = new javax.swing.JLabel();
        btnCancel = new javax.swing.JButton();
        btnExit = new javax.swing.JButton();
        lblCancel = new javax.swing.JLabel();
        lblExit = new javax.swing.JLabel();

        getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Air Vendetta Seating Reservation System");
        setName("mainForm");
        setResizable(false);
        pnlMain.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());

        pnlMain.setBorder(new javax.swing.border.CompoundBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(255, 102, 255), new java.awt.Color(204, 0, 255), new java.awt.Color(204, 0, 204), new java.awt.Color(102, 0, 102)), new javax.swing.border.LineBorder(new java.awt.Color(102, 153, 255), 2, true)));
        pnlMain.setMinimumSize(new java.awt.Dimension(300, 190));
        pnlMain.setOpaque(false);
        pnlMain.setPreferredSize(new java.awt.Dimension(275, 220));
        btnCheck.setBackground(new java.awt.Color(255, 255, 255));
        btnCheck.setText("Check");
        btnCheck.setToolTipText("Click here to check availability");
        btnCheck.setActionCommand("btnCheck");
        btnCheck.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(153, 255, 255), new java.awt.Color(102, 153, 255), new java.awt.Color(153, 0, 204), new java.awt.Color(255, 0, 255)));
        btnCheck.setDefaultCapable(false);
        btnCheck.setNextFocusableComponent(btnView);
        btnCheck.setVerifyInputWhenFocusTarget(false);
        btnCheck.addActionListener(this);
        pnlMain.add(btnCheck, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 30, 70, 20));

        lblCheck.setLabelFor(btnCheck);
        lblCheck.setText("Check seat availability");
        lblCheck.setFocusable(false);
        lblCheck.setRequestFocusEnabled(false);
        lblCheck.setVerifyInputWhenFocusTarget(false);
        pnlMain.add(lblCheck, new org.netbeans.lib.awtextra.AbsoluteConstraints(100, 30, 150, 20));

        lblView.setLabelFor(btnView);
        lblView.setText("View seating chart");
        lblView.setFocusable(false);
        lblView.setRequestFocusEnabled(false);
        lblView.setVerifyInputWhenFocusTarget(false);
        pnlMain.add(lblView, new org.netbeans.lib.awtextra.AbsoluteConstraints(100, 60, 120, 20));

        btnView.setBackground(new java.awt.Color(255, 255, 255));
        btnView.setText("View");
        btnView.setToolTipText("Click here to view a seating chart");
        btnView.setActionCommand("btnView");
        btnView.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(153, 255, 255), new java.awt.Color(102, 153, 255), new java.awt.Color(153, 0, 204), new java.awt.Color(255, 0, 255)));
        btnView.setDefaultCapable(false);
        btnView.setNextFocusableComponent(btnReserve);
        btnView.setVerifyInputWhenFocusTarget(false);
        btnView.addActionListener(this);
        pnlMain.add(btnView, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 60, 70, 20));

        btnReserve.setBackground(new java.awt.Color(255, 255, 255));
        btnReserve.setText("Reserve");
        btnReserve.setToolTipText("Click here to set up a reservation");
        btnReserve.setActionCommand("btnReserve");
        btnReserve.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(153, 255, 255), new java.awt.Color(102, 153, 255), new java.awt.Color(153, 0, 204), new java.awt.Color(255, 0, 255)));
        btnReserve.setDefaultCapable(false);
        btnReserve.setNextFocusableComponent(btnCancel);
        btnReserve.setVerifyInputWhenFocusTarget(false);
        btnReserve.addActionListener(this);
        pnlMain.add(btnReserve, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 90, 70, 20));

        lblReserve.setLabelFor(btnReserve);
        lblReserve.setText("Reserve a seat");
        lblReserve.setFocusable(false);
        lblReserve.setRequestFocusEnabled(false);
        lblReserve.setVerifyInputWhenFocusTarget(false);
        pnlMain.add(lblReserve, new org.netbeans.lib.awtextra.AbsoluteConstraints(100, 90, 120, 20));

        btnCancel.setBackground(new java.awt.Color(255, 255, 255));
        btnCancel.setText("Cancel");
        btnCancel.setToolTipText("Click here to cancel a reservation");
        btnCancel.setActionCommand("btnCancel");
        btnCancel.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(153, 255, 255), new java.awt.Color(102, 153, 255), new java.awt.Color(153, 0, 204), new java.awt.Color(255, 0, 255)));
        btnCancel.setDefaultCapable(false);
        btnCancel.setNextFocusableComponent(btnExit);
        btnCancel.setVerifyInputWhenFocusTarget(false);
        btnCancel.addActionListener(this);
        pnlMain.add(btnCancel, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 120, 70, 20));

        btnExit.setBackground(new java.awt.Color(255, 255, 255));
        btnExit.setText("Exit");
        btnExit.setToolTipText("Click here to exit application");
        btnExit.setActionCommand("btnExit");
        btnExit.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(153, 255, 255), new java.awt.Color(102, 153, 255), new java.awt.Color(153, 0, 204), new java.awt.Color(255, 0, 255)));
        btnExit.setDefaultCapable(false);
        btnExit.setNextFocusableComponent(btnCheck);
        btnExit.setVerifyInputWhenFocusTarget(false);
        btnExit.addActionListener(this);
        pnlMain.add(btnExit, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 170, 70, 20));

        lblCancel.setLabelFor(btnCancel);
        lblCancel.setText("Cancel a reservation");
        lblCancel.setFocusable(false);
        lblCancel.setRequestFocusEnabled(false);
        lblCancel.setVerifyInputWhenFocusTarget(false);
        pnlMain.add(lblCancel, new org.netbeans.lib.awtextra.AbsoluteConstraints(100, 120, 120, 20));

        lblExit.setLabelFor(btnExit);
        lblExit.setText("Exit Application");
        lblExit.setFocusable(false);
        lblExit.setRequestFocusEnabled(false);
        lblExit.setVerifyInputWhenFocusTarget(false);
        pnlMain.add(lblExit, new org.netbeans.lib.awtextra.AbsoluteConstraints(100, 170, 120, 20));

        getContentPane().add(pnlMain, new org.netbeans.lib.awtextra.AbsoluteConstraints(0, 0, -1, -1));

        pack();
    }//GEN-END:initComponents

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        //        java.awt.EventQueue.invokeLater(new Runnable() {
        //            public void run() {
        //                new mainForm().setVisible(true);
        //            }
        //        });

    }

    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton btnCancel;
    private javax.swing.JButton btnCheck;
    private javax.swing.JButton btnExit;
    private javax.swing.JButton btnReserve;
    private javax.swing.JButton btnView;
    private javax.swing.JLabel lblCancel;
    private javax.swing.JLabel lblCheck;
    private javax.swing.JLabel lblExit;
    private javax.swing.JLabel lblReserve;
    private javax.swing.JLabel lblView;
    private javax.swing.JPanel pnlMain;
    // End of variables declaration//GEN-END:variables

}

---

Basically, there is a main class that does nothign but start a thread that runs frmMain. frmMain contains buttons that launch other JFrames to accomplish certain things. The code, as it stands now, DOES work, but I simply cant figure out how to implement the listner, or more specifically, I cant figure out how to find a usable identifier from the window that passes the event (such as hide, close, minimize, and so on).