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

Question

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?

Blocked

very old question without enough details to pin-point the exact reason of the problem (DefaultTableModel fires the notifications as needed, so the error is its usage, most probably) - still confusing current readers ;) – Apprehensive

Answer 1

If you want to notify your JTable about changes of your data, use
tableModel.fireTableDataChanged()

From the documentation:

Notifies all listeners that all cell values in the table's rows may have changed. The number of rows may also have changed and the JTable should redraw the table from scratch. The structure of the table (as in the order of the columns) is assumed to be the same.

Singleaction

do you mean i call this tableModel.fireTableDataChanged() everytime when i doing updating ? – Blocked

@newbie123: If you only insert new lines, you can use fireTableRowsInserted instead. On the other hand, the implementation of DefaultTableModel.addRow should already handle that... Isn't your table refreshed by addRow? – Singleaction

Use setValueAt, DefaultTableModel fires the event. – Singleaction

One should notice though that the call must be made on casted javax.swing.table.AbstractTableModel, since interface TableModel does not have the method mentioned above – Dacoity

technically correct - but a) not needed with DefaultTableModel (its modification methods will fire the appropriate notifications), b) conceptionally wrong to let client code fire the notifications - that's the inherent responsibility of the model. So there's someting wrong with the usage of the model, unfortunately not shown in the question – Apprehensive

Answer 2

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.

Interchange

I actually found that jTable.invalidate() was the method that actually forced a redraw. – Cristinecristiona

Right, but the validate method is part of the layout process, and impacts the parents of the container too. So if you need the redo the layout, use it. docs.oracle.com/javase/7/docs/api/java/awt/… – Streetlight

Answer 3

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();
    /**/
}

Rixdollar

You don't need the jTable.setModel(tableModel) at the end as you already got the Table's model at the start. – Rorke

Answer 4

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

Delight

not, sure not, don't do that, why simulated JTable's built-in option and out from EDT – Francis

Answer 5

To inform the Jtable about data change do this - 

DefaultTableModel tableModel = new DefaultTableModel(yourData, yourColumns);
//Set data and columns in tableModel to JTable
JTable yourTable= new JTable(model);

//After data Changed fire change detector
tableModel.fireTableDataChanged();

Devastation

Answer 6

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

Landsman