Cfrgtkky

I am working on a project for tracking items, for example a basket for a shopping app.
I have decided to use a table as this is the best method I've found for being able to both add items and remove them using only a touch screen. However, I'm currently having issues with accruing the quantity of an item.
I've used the following code to update the cell which matches a specific items quantity but it seems to stop working when it hits 2 items, without producing an error message.
As a test I tried increasing the initial quantity of an item from 1 to 10 and changing the code so that instead of accruing by 1 each click, it subtracted. This however didn't work as expected instead the quantity goes straight from 10 to 0. Please someone help. I've copied in all the code other than the from code below.

 public void checkmaster(String button){



int MatchFound = 0;    

String itemnumber="";

//use button to find item no

try{

BufferedReader in2 = new BufferedReader(new FileReader("C:\Users\kyleg\Desktop\LiveOrderTestFiles\Buttons\"+button+".txt"));

String line2;

System.out.println("reading file");

while((line2 = in2.readLine()) != null){



  itemnumber=line2;



}

in2.close();} catch (IOException ex) { 

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);



}



//check master

 int MasterTableRowCount = jTable2.getRowCount();





 for(int i=0; i<MasterTableRowCount; i++){

     System.out.println(i);

   int row = i ; 



     String value = jTable2.getModel().getValueAt(row, 0).toString();



     if(value.equals(itemnumber)){

         int Quantity = Integer.parseInt(jTable2.getModel().getValueAt(row, 2).toString()); 

         updateMasterTable(row,Quantity);  

         MatchFound=1;

     }



 }



 if(MatchFound==0){addToMasterTable(itemnumber);}



}



public void updateMasterTable(int row,int Quantity){



int NewQuantity = Quantity-1; 

jTable2.setValueAt(NewQuantity, row, 1);



}



public void addToMasterTable(String itemnumber){



DefaultTableModel model = (DefaultTableModel) jTable2.getModel();

int rownumber = jTable1.getRowCount();

Vector row = new Vector();

row.add(itemnumber);

row.add("10");

row.add(rownumber+1);



model.addRow(row); 



}

The checkmaster class is called when a button is clicked on my frame. It carries a number which is used to check a storage location to see which item is connected to that button and then uses that items number to fill out the table.