public boolean act(MainForm mainForm) {

    EditForm editDialog = (EditForm) mainForm.getEditDialog();
    editDialog.setModal(true); // STOP EVERYTHING UNTIL USER SELECTS OK or CANCEL
    editDialog.setVisible(true);

    // WAIT until user does something
    if (editDialog.wasCanceled()) return false;

    return operate(mainForm, editDialog);
  }
 public boolean operate(MainForm mainForm, EditForm editDialog) {
   DefaultListModel list1 = (DefaultListModel) mainForm.getDataList().getModel();
   list1.set(0, "2343223432");
   int[] row = mainForm.getDataList().getSelectedIndices();
   if (row.length == 0) return false;
   // only edit the first one;
   int index = row[0];
   DefaultListModel list = (DefaultListModel) mainForm.getDataList().getModel();
   editDialog = (EditForm) mainForm.getEditDialog();
   try {
     double x = Double.parseDouble(editDialog.getNewX().getText());
     double y = Double.parseDouble(editDialog.getNewY().getText());
     String dataPointToAdd = x + " , " + y;
     list.set(index, dataPointToAdd);
     data.editDataPoint(index, x, y);
     return true;
   } catch (NumberFormatException | NullPointerException e) {
     e.printStackTrace();
     return false;
   }
 }