return tableModel.getColumnClass(column);
    }

    public boolean isCellEditable(int row, int column) {
        return tableModel.isCellEditable(modelIndex(row), column);
    }

    public Object getValueAt(int row, int column) {
        return tableModel.getValueAt(modelIndex(row), column);
    }

    public void setValueAt(Object aValue, int row, int column) {
        tableModel.setValueAt(aValue, modelIndex(row), column);
    }

    // Helper classes
    
    private class Row implements Comparable {
        private int modelIndex;

        public Row(int index) {
            this.modelIndex = index;
        }

        public int compareTo(Object o) {
            int row1 = modelIndex;
            int row2 = ((Row) o).modelIndex;

            for (Iterator it = sortingColumns.iterator(); it.hasNext();) {
                Directive directive = (Directive) it.next();
                int column = directive.column;
                Object o1 = tableModel.getValueAt(row1, column);
                Object o2 = tableModel.getValueAt(row2, column);

                int comparison = 0;
                // Define null less than everything, except null.
                if (o1 == null && o2 == null) {
                    comparison = 0;
                } else if (o1 == null) {
                    comparison = -1;
                } else if (o2 == null) {
                    comparison = 1;
                } else {
                    comparison = getComparator(column).compare(o1, o2);
                }
                if (comparison != 0) {
                    return directive.direction == DESCENDING ? -comparison : comparison;
                }
            }
            return 0;
        }
    }

    private class TableModelHandler implements TableModelListener {
        public void tableChanged(TableModelEvent e) {
            // If we're not sorting by anything, just pass the event along.             
            if (!isSorting()) {
                clearSortingState();
                fireTableChanged(e);
                return;
            }
                
            // If the table structure has changed, cancel the sorting; the             
            // sorting columns may have been either moved or deleted from             
            // the model. 
            if (e.getFirstRow() == TableModelEvent.HEADER_ROW) {
                cancelSorting();
                fireTableChanged(e);
                return;
            }

            // We can map a cell event through to the view without widening             
            // when the following conditions apply: 
            // 
            // a) all the changes are on one row (e.getFirstRow() == e.getLastRow()) and, 
            // b) all the changes are in one column (column != TableModelEvent.ALL_COLUMNS) and,
            // c) we are not sorting on that column (getSortingStatus(column) == NOT_SORTED) and, 
            // d) a reverse lookup will not trigger a sort (modelToView != null)
            //
            // Note: INSERT and DELETE events fail this test as they have column == ALL_COLUMNS.
            // 
            // The last check, for (modelToView != null) is to see if modelToView 
            // is already allocated. If we don't do this check; sorting can become 
            // a performance bottleneck for applications where cells  
            // change rapidly in different parts of the table. If cells 
            // change alternately in the sorting column and then outside of             
            // it this class can end up re-sorting on alternate cell updates - 
            // which can be a performance problem for large tables. The last 
            // clause avoids this problem. 
            int column = e.getColumn();
            if (e.getFirstRow() == e.getLastRow()
                    && column != TableModelEvent.ALL_COLUMNS
                    && getSortingStatus(column) == NOT_SORTED
                    && modelToView != null) {
                int viewIndex = getModelToView()[e.getFirstRow()];
                fireTableChanged(new TableModelEvent(TableSorter.this, 
                                                     viewIndex, viewIndex, 
                                                     column, e.getType()));
                return;
            }

            // Something has happened to the data that may have invalidated the row order. 
            clearSortingState();
            fireTableDataChanged();
            return;
        }
    }

    private class MouseHandler extends MouseAdapter {
        public void mouseClicked(MouseEvent e) {
            JTableHeader h = (JTableHeader) e.getSource();
            TableColumnModel columnModel = h.getColumnModel();
            int viewColumn = columnModel.getColumnIndexAtX(e.getX());
            int column = columnModel.getColumn(viewColumn).getModelIndex();
            if (column != -1) {
                int status = getSortingStatus(column);
                if (!e.isControlDown()) {
                    cancelSorting();
                }
                // Cycle the sorting states through {NOT_SORTED, ASCENDING, DESCENDING} or 
                // {NOT_SORTED, DESCENDING, ASCENDING} depending on whether shift is pressed. 
                status = status + (e.isShiftDown() ? -1 : 1);
                status = (status + 4) % 3 - 1; // signed mod, returning {-1, 0, 1}
                setSortingStatus(column, status);
            }
        }
    }

    private static class Arrow implements Icon {
        private boolean descending;
        private int size;
///        private int priority;

        public Arrow(boolean descending, int size, int priority) {
            this.descending = descending;
            this.size = size;
///            this.priority = priority;
        }

        public void paintIcon(Component c, Graphics g, int x, int y) {
	     	Color color = c.getForeground();
	     	if (color == null)
	     		color = Color.gray.darker();
            
            g.setColor(color);
            g.translate(x, y);
            
            int	dx = size / 8;
            int	dy = (c.getHeight() - size) / 2 - size / 8;

            if (!descending) {
				g.drawLine(dx, dy + 5, dx, dy + 5);
				g.drawLine(dx + 1, dy + 5, dx + 1, dy + 3);
				g.drawLine(dx + 2, dy + 3, dx + 2, dy + 1);
				g.drawLine(dx + 3, dy + 1, dx + 3, dy);
				g.setColor(c.getBackground().brighter());
				g.drawLine(dx, dy + 6, dx + 7, dy + 6);
				g.drawLine(dx + 4, dy, dx + 4, dy + 1);
				g.drawLine(dx + 5, dy + 1, dx + 5, dy + 3);
				g.drawLine(dx + 6, dy + 3, dx + 6, dy + 5);
				g.drawLine(dx + 7, dy + 5, dx + 7, dy + 6);
				g.setColor(c.getBackground());
				g.drawLine(dx + 3, dy + 2, dx + 4, dy + 2);
				g.drawLine(dx + 3, dy + 3, dx + 4, dy + 3);
				g.drawLine(dx + 2, dy + 4, dx + 5, dy + 4);
				g.drawLine(dx + 2, dy + 5, dx + 5, dy + 5);
            } else {
        		g.drawLine(dx, dy, dx + 8 - 1, dy);
        		g.drawLine(dx, dy + 1, dx, dy + 1);
        		g.drawLine(dx + 1, dy + 1, dx + 1, dy + 3);
        		g.drawLine(dx + 2, dy + 3, dx + 2, dy + 5);
        		g.drawLine(dx + 3, dy + 5, dx + 3, dy + 6);
        		g.setColor(c.getBackground().brighter());
				g.drawLine(dx + 4, dy + 5, dx + 4, dy + 6);
				g.drawLine(dx + 5, dy + 3, dx + 5, dy + 5);
				g.drawLine(dx + 6, dy + 1, dx + 6, dy + 3);
				g.drawLine(dx + 7, dy + 1, dx + 7, dy + 1);
				g.setColor(c.getBackground());
				g.drawLine(dx + 2, dy + 1, dx + 5, dy + 1);
				g.drawLine(dx + 2, dy + 2, dx + 5, dy + 2);
				g.drawLine(dx + 3, dy + 3, dx + 4, dy + 3);
				g.drawLine(dx + 3, dy + 4, dx + 4, dy + 4);	
            }
            
            g.translate(-x, -y);
        }

        public int getIconWidth() {
            return size;
        }

        public int getIconHeight() {
            return size;
        }
    }

    private class SortableHeaderRenderer implements TableCellRenderer {
        private TableCellRenderer tableCellRenderer;

        public SortableHeaderRenderer(TableCellRenderer tableCellRenderer) {
            this.tableCellRenderer = tableCellRenderer;
        }

        public Component getTableCellRendererComponent(JTable table, 
                                                       Object value,
                                                       boolean isSelected, 
                                                       boolean hasFocus,
                                                       int row, 
                                                       int column) {
            Component c = tableCellRenderer.getTableCellRendererComponent(table, 
                    value, isSelected, hasFocus, row, column);
            if (c instanceof JLabel) {
                JLabel l = (JLabel) c;
                l.setHorizontalTextPosition(JLabel.LEFT);
                int modelColumn = table.convertColumnIndexToModel(column);
                l.setIcon(getHeaderRendererIcon(modelColumn, l.getFont().getSize()));
            }
            return c;
        }
    }

    private static class Directive {
        private int column;
        private int direction;

        public Directive(int column, int direction) {
            this.column = column;
            this.direction = direction;
        }
    }
}