import java.beans.*;

import javax.swing.*;

import javax.swing.event.*;

import javax.swing.table.*;

/*

* Prevent the specified number of columns from scrolling horizontally in

* the scroll pane. The table must already exist in the scroll pane.

*

* The functionality is accomplished by creating a second JTable (fixed)

* that will share the TableModel and SelectionModel of the main table.

* This table will be used as the row header of the scroll pane.

*

* The fixed table created can be accessed by using the getFixedTable()

* method. will be returned from this method. It will allow you to:

*

* You can change the model of the main table and the change will be

* reflected in the fixed model. However, you cannot change the structure

* of the model.

*/

public class FixedColumnTable implements ChangeListener, PropertyChangeListener

{

private JTable main;

private JTable fixed;

private JScrollPane scrollPane;

/*

* Specify the number of columns to be fixed and the scroll pane

* containing the table.

*/

public FixedColumnTable(int fixedColumns, JScrollPane scrollPane)

{

this.scrollPane = scrollPane;

main = ((JTable)scrollPane.getViewport().getView());

main.setAutoCreateColumnsFromModel( false );

main.addPropertyChangeListener( this );

// Use the existing table to create a new table sharing

// the DataModel and ListSelectionModel

int totalColumns = main.getColumnCount();

fixed = new JTable();

fixed.setAutoCreateColumnsFromModel( false );

fixed.setModel( main.getModel() );

fixed.setSelectionModel( main.getSelectionModel() );

fixed.setFocusable( false );

// Remove the fixed columns from the main table

// and add them to the fixed table

for (int i = 0; i < fixedColumns; i++)

{

TableColumnModel columnModel = main.getColumnModel();

TableColumn column = columnModel.getColumn( 0 );

columnModel.removeColumn( column );

fixed.getColumnModel().addColumn( column );

}

// Add the fixed table to the scroll pane

fixed.setPreferredScrollableViewportSize(fixed.getPreferredSize());

scrollPane.setRowHeaderView( fixed );

scrollPane.setCorner(JScrollPane.UPPER_LEFT_CORNER, fixed.getTableHeader());

// Synchronize scrolling of the row header with the main table

scrollPane.getRowHeader().addChangeListener( this );

}

/*

* Return the table being used in the row header

*/

public JTable getFixedTable()

{

return fixed;

}

//

// Implement the ChangeListener

//

public void stateChanged(ChangeEvent e)

{

// Sync the scroll pane scrollbar with the row header

JViewport viewport = (JViewport) e.getSource();

scrollPane.getVerticalScrollBar().setValue(viewport.getViewPosition().y);

}

//

// Implement the PropertyChangeListener

//

public void propertyChange(PropertyChangeEvent e)

{

// Keep the fixed table in sync with the main table

if ("selectionModel".equals(e.getPropertyName()))

{

fixed.setSelectionModel( main.getSelectionModel() );

}

if ("model".equals(e.getPropertyName()))

{

fixed.setModel( main.getModel() );

}

}

}