define your own headerRender
// Create a multiline renderer, and set it for each column in
// the table.
MultiLineHeaderRenderer headerRenderer = new MultiLineHeaderRenderer();
TableColumnModel columnModel = table.getColumnModel();
for( Enumeration e = columnModel.getColumns(); e.hasMoreElements(); ) {
TableColumn column = ( TableColumn )e.nextElement();
column.setHeaderRenderer( headerRenderer );
}
/**
* An example of a multiline table header.
* To be used effectively, known header value types
* would need to be specified in an interface that
* could be tested for here. This would allow useful
* data to be queried for the additional rows in the header.
* This could be done by a specialized table model that
* returns column headers with breaks in the returned
* String from the getColumnName method that could be
* interpreted here.
**/
class MultiLineHeaderRenderer extends JTextArea
implements TableCellRenderer, Serializable {
/**
* MultiLineHeaderRenderer, default Constructor.
* Set the number of rows to two. For a production
* header renderer, the number of rows would probably
* be determined dynamically depending on the header value.
**/
public MultiLineHeaderRenderer() {
super( 2, 20 );
setOpaque( true );
}
/**
* Configure in the standard table header colors and border.
* The multiline string is a bit contrived here. Would need
* to get a real multiline header from the table model, or
* values of known types, i.e. interfaces.
**/
public Component getTableCellRendererComponent(JTable table,
Object value, boolean isSelected,
boolean hasFocus, int row, int column) {
if (table != null) {
JTableHeader header = table.getTableHeader();
if (header != null) {
setForeground(header.getForeground());
setBackground(header.getBackground());
setFont(header.getFont());
}
}
setText( (value == null) ? "Column " + column : "Column " + column + "/ n" + value.toString() );
setBorder( UIManager.getBorder("TableHeader.cellBorder") );
return this;
}
}
