JTable - dynamic update exception

Question

Hi,
My application displays a JTable based on an extended TableModel.
The TableModel observes an external source for changes, and updates the internal table data representation accordingly after which it calls
SwingUtilities.invokeLater( new Runnable()
   public void run()
      fireTableDataChanged()
})JTable then makes successive calls of TableModel.getValueAt() to repaint the table.
The problem is that the external source can add/delete rows from the table which JTable is making these calls. Eventually of course I get an exception because getValueAt() runs out of rows in the internal representation.
Making each TableModel method synchronized doesn't solve the problem because JTable will only lock the TableModel for the duration of the getValueAt() call, allowing the external source to update it in between times.
I suppose what really needs to happen is a lock on the table model which JTable is updating its view.
What approaches are other people using to solve this issue?
Thank you for reading, Dave

Answer 1

Hi Gweedo,
Thanks for your response. I agree that as small a change event as possible should be sent.
Here's a sketch of what I have:
class MyTableModel extends AbstractTableModel
   usual TableModel methods
   public synchronized Object getValueAt( int row, int col )
   public synchronized void notifyCreate( Record[] records )
      updateInternalModel();
   public synchronized void notifyUpdate( Record[] records )
      updateInternalModel();
   public synchronized void notifyDelete( int[] recordIds )
      updateInternalModel();
}The create/update/delete methods are called by a short-lived thread. The Record data originates from a CORBA server object, and my GUI application caches it based on the create/update/delete messages. When the server data changes my cache gets CORBA messages like the above, and the cache forwards these to interested objects within the GUI app, one of which is my table. The table does indeed suck the data out of the cache, based on the identity information in the record lists.
Given this, no matter how small I make the fire...Event grain, I don't really see any way to completely overcome my problem, given that notifyUpdate messages may occur in rapid succession. Unless I can know when the JTable has finished updating itself as a result of a fireTableDataChanged() event there doesn't seem to be any way to avoid the overlap between model and view updates.
Would you agree? If not would it be possible to post some code to show what you did??