JTable cell being edited after model changed.

Question

I have a fairly simple JTable, with a implementation of AbstractTableModel supplying the data. The cells are edited by using a JComboBox. I wrap these into a DefaultCellEditor. I have a KeyListener attached to the JTable listening for VK_DELETE, and when it finds one, instructs the model to delete the row represented by the selected row in the table.
Everything works fine until I want to delete a row from the table. My scenario is:
- I click in a cell, and the editor opens.
- I select an entry in the list. The editor closes, the result is rendered, and the wee yellow box around the cell is shown
- I hit the delete key.
- My key listener picks up the event, and informs the model to delete the row. I remove the row from the model and invoke fireTableDataChanged().
The result is that the row is deleted, but the table ends up with the cell editor deployed on the cell of the row below (which is now at the same row as the one I just deleted).
My tracing shows that the isCellEditable is called on the model after the delete. I don't know why.
Can anyone explain how to prevent this or what might be causing the table to think that the cell needs editing?
Thanks, Andrew

Answer 1

It will do whatever is the default. I wrap the JComboBox in a DefaultCellEditor. I can't see how the editor is involved at this point, or why the editor becomes involved after the row has been deleted.
Remember, at the time that I hit the delete key, there is no editor rendered or visible. I have the JTable displayed, a row selected, and the yellow box around one of the (editable but not currently being edited) cells. This has been achieved by editing a cell (displaying the cell editor - a combo box) and selecting an entry. The editor is removed, and the cell displayed with the (default) cell renderer for the table.
The delete action is caught by the listener on the table, the model is instructed to delete a row from its underlying data, which fires a fireTableDataChanged event.
That is all I do. After that it is all swing. The table model starts getting asked about cells being editable after I have finished deleting the row. I'll post the relevant code below if that helps.
The datamodel is of class ConstraintTableModel (see below) and the column model is of class DefaultTableColumnModel
JTable table = new JTable( dataModel, columnModel );The column model is defined liike so:
columnModel = new DefaultTableColumnModel();
TableColumn labelColumn = new TableColumn(ConstraintTableModel.LABEL_COLUMN);
labelColumn.setHeaderValue( dataModel.getColumnName(ConstraintTableModel.LABEL_COLUMN));
labelColumn.setPreferredWidth( 5 );
labelColumn.setMaxWidth( 5 );
labelColumn.setResizable( false );
TableColumn taskColumn = new TableColumn(ConstraintTableModel.TASK_COLUMN);
taskColumn.setHeaderValue( dataModel.getColumnName(ConstraintTableModel.TASK_COLUMN));
TableColumn typeColumn = new TableColumn(ConstraintTableModel.TYPE_COLUMN);
typeColumn.setHeaderValue( dataModel.getColumnName(ConstraintTableModel.TYPE_COLUMN));
columnModel.addColumn( labelColumn );
columnModel.addColumn( taskColumn );
columnModel.addColumn( typeColumn );I add the key listener like so:
table.addKeyListener( new KeyAdapter()
    public void keyPressed( KeyEvent e )
      if( e.getKeyCode() == KeyEvent.VK_DELETE )
        log.debug("Delete pressed in listener attached to table ");
        JTable t = (JTable) e.getSource();
        int selectedRow = t.getSelectedRow();
        if( selectedRow >= 0 )
          log.debug("  Removing row " + selectedRow);
          ((ConstraintTableModel)t.getModel()).removeRow(selectedRow);
        log.debug("Finished with key press");
  } );The cell editor is created like this:
JComboBox taskEditorComponent = new JComboBox( tasksModel );
taskEditorComponent.setFont( GanttChart.tableFont );
taskEditorComponent.setBackground( Color.WHITE );
DefaultCellEditor taskEditor = new DefaultCellEditor(taskEditorComponent);
taskEditor.setClickCountToStart( 1 );
table.setDefaultEditor( GanttTask.class, taskEditor );The model is coded like so:
class ConstraintTableModel extends AbstractTableModel
    // Constants
    public static final int LABEL_COLUMN = 0;
    public static final int TASK_COLUMN = 1;
    public static final int TYPE_COLUMN = 2;
    private Vector          columnNames;
    private ArrayList       dataRows;
    public ConstraintTableModel()
        super();
        this.buildDataVector();
        this.addPrimerRow();
     * Every row in the table is a GanttConstraint. Therefore when deciding what to
     * display in any particular column of the table, we need to determine what the
     * column is, and then use the informatino in the GanttConstraint to go out to the
     * lookup and get the relevant object, and value to display.
    public Object getValueAt( int row, int col )
        Object          returnObject = "";
        GanttConstraint aConstraint = (GanttConstraint) this.getDataRows().get( row );
        // We're rendering the task column. If there's no task id (partially filled in row)
        // return blank otherwise return the master task
        else if( col == ConstraintTableModel.TASK_COLUMN )
            if( aConstraint.getMasterId() != null )
                GanttTask masterTask = (GanttTask) real.getLookup().get( aConstraint.getMasterId() );
                returnObject = masterTask;
        // We're rendering the type column. If there's no type (partially filled in row)
        // return blank otherwise return the constraint type
        else if( col == ConstraintTableModel.TYPE_COLUMN )
            if( aConstraint.getType() != null )
                GanttConstraintType constraintType = (GanttConstraintType) GanttConstraintType.getConstraintTypes()
                                                                                                 .get( aConstraint.getType()
                                                                                                                  .intValue() );
                returnObject = constraintType;
        return returnObject;
     * When we receive this message, we are handed an object of the type specified in
     * getColumnClass. We need to take this object and place the relevant information into
     * the GanttConstraint row in the table model.
     * Depending on whether the row being modified is an existing row or a new row, set
     * the state of the constraint appropriately.
     * @see javax.swing.table.TableModel#setValueAt(java.lang.Object, int, int)
    public void setValueAt( Object value, int row, int col )
        log.debug( "+setValueAt (row/col) " + row + "/" + col );
        if ( value == null )
            log.debug( "  handed a null value. Returning" );
            return;
        GanttConstraint aConstraint = (GanttConstraint) this.getDataRows().get( row );
        // If we are modifying the primer row, add another primer row.
        if( row == ( this.getRowCount() - 1 ) ) // Last row is always the primer
            log.debug( "  adding a primer row" );
            this.addPrimerRow();
        // We're modifying the Task data. Get the GanttTask handed to us and place it
        // into the master slot in the constraint.
        if( col == ConstraintTableModel.TASK_COLUMN ) // Task
            log.debug( "  updating the master task" );
            GanttTask selectedTask = (GanttTask) value;
            aConstraint.setMaster( selectedTask );
        // We're modifying the Type data. Get the GanttConstraintType handed to us and place it
        // into the type slot in the constraint.
        if( col == ConstraintTableModel.TYPE_COLUMN ) // Constraint type
            log.debug( "  updating the constraint type" );
            GanttConstraintType selectedConstraintType = (GanttConstraintType) value;
            aConstraint.setType( selectedConstraintType.getType() );
        log.debug( "-setValueAt" );
    public Class getColumnClass( int col )
        Class columnClass = super.getColumnClass( col );
        if( col == ConstraintTableModel.LABEL_COLUMN )
            columnClass = String.class;
        if( col == ConstraintTableModel.TASK_COLUMN )
            columnClass = GanttTask.class;
        if( col == ConstraintTableModel.TYPE_COLUMN )
            columnClass = GanttConstraintType.class;
        return columnClass;
    // We are handing the data storage
    public void setDataRows( ArrayList dataRows )
        this.dataRows = dataRows;
    public boolean isCellEditable( int row, int col )
        log.debug( "+isCellEditable (row/col) " + row + "/" + col );
        if( !real.canEdit() )
            return false;
        if( ( col == ConstraintTableModel.TASK_COLUMN ) ||
                ( col == ConstraintTableModel.TYPE_COLUMN ) )
            return true;
        else
            return false;
    // We are handing the data storage
    public ArrayList getDataRows()
        return this.dataRows;
    public String getColumnName( int column )
        return (String) this.getColumnNames().get( column );
     * Clean up rows that do not have both the master task and type set. Not interested in them
    public void removeDirtyRows()
        log.debug( "+removeDirtyRows" );
        Iterator dataIterator = this.getDataRows().iterator();
        while( dataIterator.hasNext() )
            GanttConstraint element = (GanttConstraint) dataIterator.next();
            if( ( element.getMasterId() == null ) || ( element.getType() == null ) )
                element.setTransient();
                dataIterator.remove();
        fireTableDataChanged();
        log.debug( "-removeDirtyRows" );
    public void removeRow( int row )
        log.debug( "+removeRow(" + row + ")" );
        if( row < this.getDataRows().size() )
            GanttConstraint aConstraint = (GanttConstraint) this.getDataRows().get( row );
            this.getDataRows().remove( row );
            if( aConstraint.isClone() )
                aConstraint.setDeleted();
            else
                aConstraint.setTransient();
                getClone().removeConstraint( aConstraint );
            fireTableDataChanged();
        if( this.getRowCount() == 0 )
            this.addPrimerRow();
        log.debug( "-removeRow" );
    public void clearRow( int row )
        log.debug( "+clearRow(" + row + ")" );
        if( row < this.getDataRows().size() )
            GanttConstraint aConstraint = (GanttConstraint) this.getDataRows().get( row );
            aConstraint.setMasterId( null );
            aConstraint.setType( null );
            fireTableRowsUpdated( row, row );
        log.debug( "-clearRow" );
    public int getColumnCount()
        return getColumnNames().size();
    public int getRowCount()
        return dataRows.size();
     * The table will be filled with constraints relevant to 'clone'.
    private void buildDataVector()
        ArrayList  data = new ArrayList( 1 );
        Collection allConstraints = getClone().getStartConstraints();
        allConstraints.addAll( getClone().getEndConstraints() );
        Iterator constraintIter = allConstraints.iterator();
        while( constraintIter.hasNext() )
            GanttConstraint element = (GanttConstraint) constraintIter.next();
            if( element.getType().equals( GanttConstraint.START_SPECIFIED ) ||
                    element.getType().equals( GanttConstraint.FINISH_FROM_DURATION ) )
                continue;
            else
                data.add( element );
        this.setDataRows( data );
    private Vector getColumnNames()
        if( columnNames == null )
            columnNames = new Vector( 3 );
            columnNames.add( " " ); // Needs space otherwise all the headers disappear
            columnNames.add( "Task" );
            columnNames.add( "Constraint" );
        return columnNames;
    private void addPrimerRow()
        log.debug( "+addPrimerRow" );
        // Create a constraint for the 'clone' task. Set it as transient until validation
        // where we will deal with it if necessary.
        GanttConstraint primer = new GanttConstraint( real.getLookup() );
        primer.setObjectId( chart.getNextUniqueId() );
        primer.setTransient();
        primer.setSlave( getClone() );
        primer.setProject( getClone().getProject() );
        getClone().addConstraint( primer );
        this.getDataRows().add( primer );
        int lastRow = this.getRowCount() - 1;
        fireTableRowsInserted( lastRow, lastRow );
        log.debug( "-addPrimerRow" );