Java Swing :- Window Application ( Model Phase 1 TableModel Program)

package model;

import java.util.ArrayList;
import javax.swing.event.TableModelListener;
import javax.swing.table.TableModel;

/**
 *
 * @author Amol
 */
public class MyTableModel implements TableModel {

    private String columnName[] = {"roll", "total", "obtain"};
    private Class[] classname = {String.class, String.class, String.class};
    ArrayList<Person> personList = new ArrayList<Person>();

    public MyTableModel(ArrayList<Person> personList) {
        this.personList = personList;
    }

    public int getRowCount() {
        int size = personList.size();
        return size;
    }

    public int getColumnCount() {
        return columnName.length;

    }

    public String getColumnName(int columnIndex) {
        return columnName[columnIndex];
    }

    public Class<?> getColumnClass(int columnIndex) {
        return classname[columnIndex];

    }

    public boolean isCellEditable(int rowIndex, int columnIndex) {
        return true;

    }

    public Object getValueAt(int rowIndex, int columnIndex) {
        Person person = personList.get(rowIndex);
        switch (columnIndex) {
            case 0:
                return person.getRoll();
            case 1:
                return person.getTotal();
            case 2:

                return person.getObtain();
        }
        return null;
    }

    public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
        Person person = personList.get(rowIndex);
        switch (columnIndex) {
            case 0:
                person.setRoll((String) aValue);
                break;
            case 1:
                person.setTotal((String) aValue);
                break;
            case 2:
                person.setObtain((String) aValue);
                break;
        }

    }

    public void addTableModelListener(TableModelListener l) {
    }

    public void removeTableModelListener(TableModelListener l) {
    }
}