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Refresh JFrame contents DefaultTableModel

I'm trying to figure out how to make a table window update once the model has changed using an example from another site. Everything works but I can't figure how to refresh the window once the table model has changed.
EDIT: I used the suggestion from Bell and re-arranged some things so that the constructor calls my getmodel3 method to populate the table. I thought I could use the setmodel method to change the model and update the table but it isn't working as I thought. Here's what I thought would, but doesn't happen:
The main method creates a new instance of the table using the model passed from the getmodel3 method.
After the table is constructed I call the setmodel method to load different data into a new model using the returned model from getmodel4.
The instance from step 1 is updated with new model data and the new data is shown in the table.
What actually happens is, a new instance is created and uses the model returned from getmodel3, then the setmodel method runs and updates the model variable from a different set of data, but the table doesn't show the change.
public class myTable extends JFrame
{
public volatile DefaultTableModel model = (DefaultTableModel) myTable.getmodel3();
public void setmodel(DefaultTableModel newModel)
{
this.model = newModel;
}
public myTable()
{
JTable table = new JTable( model );
JScrollPane scrollPane = new JScrollPane( table );
getContentPane().add( scrollPane );
JPanel buttonPanel = new JPanel();
getContentPane().add( buttonPanel, BorderLayout.SOUTH );
}
public static void main(String[] args)
{
myTable frame = new myTable();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);
frame.setmodel(getmodel4());
}
Here is getmodel3 which is identical to getmodel4 except they point to different database files for different data.
public static DefaultTableModel getmodel3(){
Vector<Object> columnNames = new Vector<Object>();
Vector<Object> data = new Vector<Object>();
try
{
// Connect to an Access Database
String url = "jdbc:sqlite:c:\\sqlite3\\test.db";
Connection conn = DriverManager.getConnection(url);
// Read data from a table
String sql = "Select * from Tasks";
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.addElement( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement( rs.getObject(i) );
}
data.addElement( row );
}
rs.close();
stmt.close();
conn.close();
}
catch(Exception e)
{
System.out.println( e );
}
// Create table with database data
DefaultTableModel model = new DefaultTableModel(data, columnNames)
{
#Override
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
System.out.println("got model");
return model;
}

You can use existing model by using table.getModel() and set new/existing model using table.setModel(yourModel)
DefaultTableModel model = (DefaultTableModel) table.getModel();
// do modification here
table.setModel(model);

Well, with some of your help I finally figured it out. setModel wasn't working because 1, it wasn't accessible from the scope of the method where I tried to use it, and 2 I tried to make my own setter setmodel but I had no idea what I was doing :).
In the end, I initialized in an easier to reach place so I didn't mess with objects in other methods. Here is the working result that loads a table when main is called and later I can call the update method to reload it. Thanks for the help folks.
public class able extends JFrame
{
//initialize here for easy access. getmodel3() is the model getter method and
//returns the defaultTableModel object
private static able frame = new able();
private static JTable table = new JTable( getmodel3() );
//Start all main stuff here using the previously initialized objects.
public static void main(String[] args)
{
JScrollPane scrollPane = new JScrollPane( table );
frame.getContentPane().add( scrollPane );
JPanel buttonPanel = new JPanel();
frame.getContentPane().add( buttonPanel, BorderLayout.SOUTH );
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);
}
public static void update()
{
table.setModel(getmodel3());
}
//This method makes the table model from sql result set and returns it.
//(found online somewhere thanks to whoever wrote it)
public static DefaultTableModel getmodel3(){
Vector<Object> columnNames = new Vector<Object>();
Vector<Object> data = new Vector<Object>();
try
{
// Connect to an Access Database
String url = "jdbc:sqlite:c:\\sqlite3\\test.db";
Connection conn = DriverManager.getConnection(url);
// Read data from a table
String sql = "Select * from Tasks";
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.addElement( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement( rs.getObject(i) );
}
data.addElement( row );
}
rs.close();
stmt.close();
conn.close();
}
catch(Exception e)
{
System.out.println( e );
}
// Create table with database data
DefaultTableModel model3 = new DefaultTableModel(data, columnNames)
{
#Override
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
System.out.println("got model");
return model3;
}
public static DefaultTableModel getmodel4(){
Vector<Object> columnNames = new Vector<Object>();
Vector<Object> data = new Vector<Object>();
try
{
// Connect to an Access Database
String url = "jdbc:sqlite:c:\\sqlite3\\test2.db";
Connection conn = DriverManager.getConnection(url);
// Read data from a table
String sql = "Select * from Tasks";
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.addElement( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement( rs.getObject(i) );
}
data.addElement( row );
}
rs.close();
stmt.close();
conn.close();
}
catch(Exception e)
{
System.out.println( e );
}
// Create table with database data
DefaultTableModel model3 = new DefaultTableModel(data, columnNames)
{
#Override
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
System.out.println("got model");
return model3;
}
}

How to change names of the columns in JTable

I need to change the column's names in the JTable. Now names are automatically taken from the database. I want to change names of columns like "country" and "sum" for example to "Name of the country" and "Sum of the netamount". I use Vector to create my JTable, so it's a problem to change the names.
My code:
public class App extends JFrame{
public App() {
Vector<Object> columnNames = new Vector<Object>();
Vector<Object> data = new Vector<Object>();
...
stmt = c.createStatement();
query = "select * from country";
rs = stmt.executeQuery(query);
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
for (int i = 1; i <= columns; i++)
{
columnNames.addElement(md.getColumnName(i));
}
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement(rs.getObject(i) );
}
data.addElement(row);
}
rs.close();
stmt.close();
c.close();
}
catch(Exception e)
{
System.out.println(e);
}
DefaultTableModel model = new DefaultTableModel(data, columnNames)
{
#Override
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
JTable table = new JTable( model );
JScrollPane scrollPane = new JScrollPane( table );
getContentPane().add( scrollPane );
JPanel buttonPanel = new JPanel();
getContentPane().add( buttonPanel, BorderLayout.SOUTH );
}
public static void main(String[] args)
{
App frame = new App();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);
}
}

If you want to manually control the column names you can do something like:
String[] columnNames = {"Column1", "Column2", "Column3", "Column4"};
DefaultTableModel model = new DefaultTableModel(columnNames, 0)
You will no longer need the meta data for the column names.
Then when you loop through the ResultSet you just do:
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement(rs.getObject(i) );
}
model.addRow( row )
}
JTable table = new JTable( model );

How to fix JProgressBar using SwingWorker?

I wrote the following code that I thought would work, I wanted to open a new JFrame on a button click that shows a progress bar that gets updated:
b3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int numOfRows = getRows();//function that returns number of rows
int numOfColumns = getColumns();//function that returns number of columns
String myquery = "select * from foo_table";
rs = null;
try {
rs = st.executeQuery(myquery);
// extract column information
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
columnData = new ArrayList<String>(columnCount);
for (int i = 1; i <= columnCount; i++) {
columnData.add(rsmd.getColumnName(i));
}
// sql result data
table_ResQues.setModel(new ListTableModel(Collections.<List<Object>>emptyList(), Collections.<String>emptyList()));
rowData = new ArrayList<List<Object>>();
final JFrame progFrame = new JFrame("Processing...");
JPanel mainPPanel = new JPanel(new BorderLayout());
JProgressBar progBar = new JProgressBar(0,100);
progFrame.setBounds(850,300,400,100);
progFrame.setVisible(true);
progBar = new JProgressBar(0,100);
mainPPanel.add(progBar, BorderLayout.NORTH);
progFrame.add(mainPPanel);
progFrame.setVisible(true);
int countRows = 0;
int area = numOfRows*numOfColumns;
int totalTime = area % 200000;
int xPerSec = totalTime/100;
while (rs.next()) {
row = new ArrayList<Object>(columnCount);
for (int i = 0; i < columnCount; i++) {
row.add(rs.getObject(i + 1));
}
rowData.add(row);
countRows++;
if(countRows*numOfColumns == 200000){
progBar.setValue(xPerSec++);
countRows = 0;
}
}
table_ResQues.setModel(new ListTableModel(rowData, columnData));
}catch (SQLException e1) {
JOptionPane.showMessageDialog(frame, e1.getMessage(), "SQL Exception", JOptionPane.ERROR_MESSAGE);
e1.printStackTrace();
}
});
But when googling my problem I realized it is a threading issue, and I never had any experience with threading or SwingWorker, can anyone help me implement what I want using SwingWorker? Should my while-loop be the one that's running in the background? should it be a class by itself? Sorry, i'm really confused.

I have solved it by creating a new class that extends SwingWorker and overriding it's methods. Thanks for the help in the comments.

Column header do not show up even after wrapping the table with JScrollPane

This is a followup question to Display database table with swing
I wrapped my table to a JScrollPane but the columns' headers are still not showing up!
Can anyone tell me what is wrong?
try {
con = (Connection) DriverManager.getConnection(DATABASE_URL , USERNAME, PASSWORD);
stmt = (Statement) con.createStatement();
ResultSet rs = stmt.executeQuery(QUERY_FIND_ITEMS);
{
ResultSetMetaData md = (ResultSetMetaData) rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.add( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
ArrayList row = new ArrayList(columns);
for (int i = 1; i <= columns; i++)
{
row.add( rs.getObject(i) );
}
data.add( row );
}
}
}
catch (SQLException e)
{
System.out.println( e.getMessage() );
}
Vector<String> columnNamesVector = new Vector();
Vector dataVector = new Vector();
for (int i = 0; i < data.size(); i++)
{
ArrayList subArray = (ArrayList)data.get(i);
Vector subVector = new Vector();
for (int j = 0; j < subArray.size(); j++)
{
subVector.add(subArray.get(j));
}
dataVector.add(subVector);
}
for (int i = 0; i < columnNames.size(); i++ ) {
columnNamesVector.add(columnNames.get(i));
}
// Create table with database data
JTable table = new JTable(dataVector, columnNamesVector)
{
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
JScrollPane scrollPane =new JScrollPane(table);
getContentPane().add( scrollPane, BorderLayout.WEST );
JPanel buttonPanel = new JPanel();
getContentPane().add( buttonPanel, BorderLayout.SOUTH );
table.setForeground(Color.BLUE);

catch (SQLException e)
{
System.out.println( e.getMessage() );
}
The code after the end of the catch block will not work correctly if the DB query fails. Best to include that code within the try block.
And a tip: change
System.out.println( e.getMessage() );
to
e.printStackTrace();
Both shorter & more informative.

jTable in GUI (java) does not show all data from database! error in TableModel?

This is a last resort. I'm studying development of Information Systems and even my teachers can't solve this... this is a nut for you to crack!!
This is the problem: My jTable in GUI gives me this:
This is what Microsoft Management Studio shows me:
As you can tell the jTable (GUI) has got 2 main problems:
The columnname "Name" does not contain any information. And it should? Why isn't it showing?
Since as you can tell, the table contains several columns, too many to even show. I therefore want to "add a restriction" that changes so that the jTable only shows the first 6 columns.
This is the code for the "creation of the table", in the DataAccessLayer:
private TableModel getResultSetAsDefaultTableModel(ResultSet rs) {
try {
String[] columnHeadings = new String[0];
Object[][] dataArray = new Object[0][0];
ResultSetMetaData md = rs.getMetaData();
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
String columnName = md.getColumnName(i);
columnHeadings = Arrays.copyOf(columnHeadings, columnHeadings.length + 1);
columnHeadings[i - 1] = columnName;
}
int r = 0;
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; i++) {
row[i - 1] = rs.getObject(i);
}
dataArray = Arrays.copyOf(dataArray, dataArray.length + 1);
dataArray[r] = row;
r++;
}
DefaultTableModel dtm = new DefaultTableModel(dataArray, columnHeadings) {
public boolean isCellEditable(int row, int column) {
return false;
}
};
return dtm;
} catch (SQLException ex) {
Logger.getLogger(Dataaccesslayer.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
If you want me to show you the path of the code (frame, controller) just say so and I'll post it.
I would be so thankful if anyone can solve this...
Regards,
Christian

I think it is because in your for loop it should say i = 0; and not i = 1; since the first information (the name) is at index 0 right ?
In your case it could be enough to just leave the for-loop as it is and change this line to:row[i - 1] = rs.getObject(i-1);
To hide or show columns you could call setMin setMax and setPreferredWidth on your TableColumn.

Change your method like next, I think it helps you:
private TableModel getResultSetAsDefaultTableModel(ResultSet rs) {
try {
List<String> columnHeadings = new ArrayList<String>();
Object[][] dataArray = new Object[0][0];
ResultSetMetaData md = rs.getMetaData();
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
columnHeadings.add(md.getColumnName(i));
}
int r = 0;
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; i++) {
row[i-1] = rs.getObject(i);
}
dataArray = Arrays.copyOf(dataArray, dataArray.length + 1);
dataArray[r] = row;
r++;
}
DefaultTableModel dtm = new DefaultTableModel(dataArray,columnHeadings.toArray(new Object[columnHeadings.size()])) {
public boolean isCellEditable(int row, int column) {
return false;
}
};
return dtm;
} catch (SQLException ex) {
Logger.getLogger(Dataaccesslayer.class.getName()).log(Level.SEVERE,null, ex);
}
return null;
}
For showing not all columns use dtm.setColumnCount(2);. Here 2 is column count to show.