[java] JTable How to refresh table model after insert delete or update the data.

This is my jTable

private JTable getJTable() {
    String[] colName = { "Name", "Email", "Contact No. 1", "Contact No. 2",
            "Group", "" };
    if (jTable == null) {
        jTable = new JTable() {
            public boolean isCellEditable(int nRow, int nCol) {
                return false;
            }
        };
    }
    DefaultTableModel contactTableModel = (DefaultTableModel) jTable
            .getModel();
    contactTableModel.setColumnIdentifiers(colName);
    jTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    return jTable;
}

I will call this method to retrieve the data from database and put it into table model

public void setUpTableData() {
    DefaultTableModel tableModel = (DefaultTableModel) jTable.getModel();
    ArrayList<Contact> list = new ArrayList<Contact>();
    if (!con.equals(""))
        list = sql.getContactListsByGroup(con);
    else
        list = sql.getContactLists();
    for (int i = 0; i < list.size(); i++) {
        String[] data = new String[7];

            data[0] = list.get(i).getName();
            data[1] = list.get(i).getEmail();
            data[2] = list.get(i).getPhone1();
            data[3] = list.get(i).getPhone2();
            data[4] = list.get(i).getGroup();
            data[5] = list.get(i).getId();

        tableModel.addRow(data);
    }
    jTable.setModel(tableModel);
}

Currently I was using this method to refresh the table after updating the table data. I will first clear the table

DefaultTableModel tableModel = (DefaultTableModel) jTable.getModel();
tableModel.setRowCount(0);

and then restructure the table model again so it will refresh the jTable. But I was thinking is there any best practices or better way to do that?

The faster way for your case is:

    jTable.repaint(); // Repaint all the component (all Cells).

The optimized way when one or few cell change:

    ((AbstractTableModel) jTable.getModel()).fireTableCellUpdated(x, 0); // Repaint one cell.

DefaultTableModel dm = (DefaultTableModel)table.getModel();
dm.fireTableDataChanged(); // notifies the JTable that the model has changed

try this

public void setUpTableData() {
    DefaultTableModel tableModel = (DefaultTableModel) jTable.getModel();

    /**
    * additional code.
    **/
    tableModel.setRowCount(0);
    /**/
    ArrayList<Contact> list = new ArrayList<Contact>();
    if (!con.equals(""))
        list = sql.getContactListsByGroup(con);
    else
        list = sql.getContactLists();
    for (int i = 0; i < list.size(); i++) {
        String[] data = new String[7];

        data[0] = list.get(i).getName();
        data[1] = list.get(i).getEmail();
        data[2] = list.get(i).getPhone1();
        data[3] = list.get(i).getPhone2();
        data[4] = list.get(i).getGroup();
        data[5] = list.get(i).getId();

        tableModel.addRow(data);
    }
    jTable.setModel(tableModel);
    /**
    * additional code.
    **/
    tableModel.fireTableDataChanged();
    /**/
}

Would it not be better to use java.util.Observable and java.util.Observer that will cause the table to update?

I did it like this in my Jtable its autorefreshing after 300 ms;

DefaultTableModel tableModel = new DefaultTableModel(){
public boolean isCellEditable(int nRow, int nCol) {
                return false;
            }
};
JTable table = new JTable();

Timer t = new Timer(300, new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                addColumns();
                remakeData(set);
                table.setModel(model);
            }
        });
        t.start();

private void addColumns() {
        model.setColumnCount(0);
        model.addColumn("NAME");
            model.addColumn("EMAIL");} 

 private void remakeData(CollectionType< Objects > name) {
    model.setRowCount(0);
    for (CollectionType Objects : name){
    String n = Object.getName();
    String e = Object.getEmail();
    model.insertRow(model.getRowCount(),new Object[] { n,e });
    }}

I doubt it will do good with large number of objects like over 500, only other way is to implement TableModelListener in your class, but i did not understand how to use it well. look at http://download.oracle.com/javase/tutorial/uiswing/components/table.html#modelchange