스윙 테이블의 데이터 추가 질문입니다...^^;

import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JPanel;
import javax.swing.table.TableColumn;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import java.util.Vector;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;

public class Testing extends JFrame implements ActionListener{

    private DefaultTableModel tmodel;
    private JTable table;
    private JTextField itext1;
    private JTextField itext2;
    private JButton submit;
    private String colName = "필드";
    private int colCount = 0;

    public Testing(){
        Vector rowVec1 = new Vector();
        rowVec1.addElement("1-1");
        rowVec1.addElement("1-2");

        Vector rowVec2 = new Vector();
        rowVec2.addElement("2-1");
        rowVec2.addElement("2-2");

        Vector v_field = new Vector();
        colCount++;
        v_field.addElement(colName+ colCount);
        colCount++;
        v_field.addElement(colName+ colCount);

        Vector v_test = new Vector();
        v_test.addElement(rowVec1);
        v_test.addElement(rowVec2);

        this.tmodel = new DefaultTableModel(v_test, v_field);

        table = new JTable(tmodel);

        itext1 = new JTextField(10);
        itext2 = new JTextField(10);
        submit = new JButton("SUBMIT");
        submit.addActionListener(this);

        JPanel form = new JPanel();
        form.add(itext1);
        form.add(itext2);
        form.add(submit);

        this.getContentPane().setLayout(new BorderLayout());
        this.getContentPane().add(table, BorderLayout.CENTER);
        this.getContentPane().add(form, BorderLayout.SOUTH);

        this.addWindowListener(
                new WindowAdapter(){
                    public void windowClosing(WindowEvent e){
                        System.exit(0);
                    }
                }
        );

        this.setVisible(true);
        this.pack();
    }

    public void actionPerformed(ActionEvent e){
        Vector values = new Vector();
        values.addElement(this.itext1.getText());
        values.addElement(this.itext2.getText());
        colCount++;
        this.tmodel.addColumn(colName+ colCount, values);
    }

    public static void main(String[] args){
        JFrame testing = new Testing();
    }
}