jCombobox giving incremental value error on jTable

I am having problems with my code below, the code below shows a jComboBox being populated, when i select an item from this list it is added to the jTable below it.

There is alos code to check for duplicate entries ont he table. If a duplicate entry is found it should increase the qty column by one and not create a seperate entry.

This is where the problem comes in, when I press the back button on this screen and go to a different screen and then come back via same route as the first time, I get an incrementally different qty added to the table row/cell.

I have also included the code that populates the Round Details depending on Round Drop selected from table, for reference, but Im fairly certain the problem lies in the below code. The navigation is as follows...

To get to the below screen... Round Drop panel table of round drops) >> click on table row and taken to associated round details panel >> pressing the Till button takes user to screen with code below...

Test results:

First pass through below code using navigation above gives results as expected

Second pass gives an initial value of 2 (instead of one), and duplicate row increases qty by 2 instead of one

Third pass gives an initial value of 3 (instead of one), and duplicate row increases qty by 3 instead of one

Fourth pass gives an initial value of 4 (instead of one), and duplicate row increases qty by 4 instead of one

...and so on.

Any help, guidance on solution or a better design would be hugely appreciated.

Thanks

/*************Code sample ********************************/ public void tillOperations(String sourceCall) {

    final DefaultTableModel model = (DefaultTableModel)main.tillPanel.tblTillSale.getModel();
    if (ma开发者_JAVA技巧in.tillPanel.cmbTillProdSelect.getItemCount() < 1) {
        for (int d = 0; d < roundStockObj.length ; d++) {
            main.tillPanel.cmbTillProdSelect.addItem(roundStockObj[d].getDescription());
        }}
    main.tillPanel.tblTillSale.removeRowSelectionInterval(0, model.getRowCount() - 1);

    main.tillPanel.cmbTillProdSelect.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent f)
        {
            int qty = 1;
            for (int index = 0; index < 4; index++) {
                addSelectedItem[index] = "";
            }
            int row;
            selectedItem = null;
            main.tillPanel.tblTillSale.removeRowSelectionInterval(0, model.getRowCount() - 1);
            selectedItem = main.tillPanel.cmbTillProdSelect.getSelectedItem();

            for (int d = 0; d < roundStockObj.length; d++) {

                if (selectedItem.equals(roundStockObj[d].getDescription())) {    
                    addSelectedItem[0] = roundStockObj[d].getDescription();
                    addSelectedItem[1] = Integer.toString(qty);
                    addSelectedItem[2] = Double.toString(roundStockObj[d].getPrice()).trim();
                    addSelectedItem[3] = Double.toString(roundStockObj[d].getPrice()).trim();
                    //break;
                }
            }

            if(model.getRowCount() == 0) { //check if model is empty
                model.addRow(new String[]{addSelectedItem[0], addSelectedItem[1], addSelectedItem[2], addSelectedItem[3]});
            }
            else { //check if there is a duplicate row
                int duplicateRow = -1;
                for (row = 0 ; row < model.getRowCount(); row++) {
                    if(addSelectedItem[0].equals(main.tillPanel.tblTillSale.getModel().getValueAt(row,0))) {
                        duplicateRow = row;
                        break;
                    }
                }

                if(duplicateRow == -1) { //if there is no duplicate row, append
                    model.addRow(new String[]{addSelectedItem[0], addSelectedItem[1], addSelectedItem[2], addSelectedItem[3]});
                }
                else { //if there is a duplicate row, update
                    main.tillPanel.jLabel1.setText(addSelectedItem[1]);
                    DecimalFormat fmtObj = new DecimalFormat("####0.00");
                    int currentValue = Integer.parseInt(main.tillPanel.tblTillSale.getValueAt(row, 1).toString().trim());
                    int newValue = currentValue + 1;
                    Integer newValueInt = new Integer(newValue);
                    model.setValueAt(newValueInt, row, 1);

                    double unitPrice = Double.parseDouble(main.tillPanel.tblTillSale.getValueAt(row, 2).toString().trim());
                    double newPrice = newValue * unitPrice;
                    Double newPriceDbl = new Double(newPrice);
                    main.tillPanel.tblTillSale.setValueAt(fmtObj.format(newPriceDbl), row, 3);
                }
            }

            main.tillPanel.tblTillSale.removeRowSelectionInterval(0, model.getRowCount() - 1);
            for (int index = 0; index < 4; index++) {
                addSelectedItem[index] = "";
            }
        }
    });

//This code loads the specific Round Details, based on the selection form the round drops table

public void displayRoundDropDetails() {
    DefaultTableModel model = (DefaultTableModel)main.selectRoundDropPanel.tblSelectRoundDrop.getModel();

    if (!loaded) {
    for (int d = 0; d < roundDropsData.length; d++) {
        if (roundDropsData[d][0].equals(defaultRoundID)) {
            model.addRow(new Object[]{roundDropsData[d][3], roundDropsData[d][2],
                    roundDropsData[d][4], roundDropsData[d][5]});
        }
    }
    loaded = true;
    }
    main.selectRoundDropPanel.tblSelectRoundDrop.addMouseListener(new MouseAdapter()
    {
        public void mouseClicked(MouseEvent evt)
        {
            int row = 0;
            row = main.selectRoundDropPanel.tblSelectRoundDrop.getSelectedRow();
            for (int index = 0; index < roundDropsData.length; index++) {
                if (roundDropsData[index][3].equals(
                        main.selectRoundDropPanel.tblSelectRoundDrop.getModel().getValueAt(row, 0))) {

                    main.roundDetailsPanel.txtRoundDetailsAddress.setText(roundDropsData[index][6] + "\n"
                            + roundDropsData[index][7] + ", " + roundDropsData[index][8] + "\n" +
                            roundDropsData[index][9]);

                    main.roundDetailsPanel.lblRoundDetailsName.setText(roundDropsData[index][2]);
                    main.roundDetailsPanel.txtRoundDetailsInstuct.setText(roundDropsData[index][10]);
                    main.roundDetailsPanel.txtDropDetailsIn.setText(roundDropsData[index][4]);
                    main.roundDetailsPanel.txtDropDetailsOut.setText(roundDropsData[index][5]);
                    main.roundDetailsPanel.txtRoundDetailsInstruct.setText(roundDropsData[index][12]);
                    break;
                }
            }
        Globals.CURRENT_COMPONENT = "selectRoundDropPanel";
        showRoundDetailsPanel();
        }
    });
}

Try changing the listener for JComboBox. try using stateChangeListener.