Swing: table cell rendering doesn't work right for JXTable?

Question

I'm trying to override the highlight color of a JXTable based on the value of certain row items. Here's an example where the highlight is green if the row item value has getNumber() % 2 == 0.

It works fine for JTable, but for JXTable, it looks like the table cell renderer doesn't work unless the rows in question are selected. Why does it behave this way, and how do I fix it?

import java.awt.Color;
import java.awt.Component;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumnModel;
import org.jdesktop.swingx.JXTable;
import ca.odell.glazedlists.BasicEventList;
import ca.odell.glazedlists.EventList;
import ca.odell.glazedlists.SortedList;
import ca.odell.glazedlists.gui.TableFormat;
import ca.odell.glazedlists.swing.EventTableModel;

public class TableRendererExample {
    static public enum ItemKey {
        NAME("name") {
            @Override public String getStringFromItem(Item item) {
                return item.getName();
            }
        }, 
        NUMBER("#") {
            @Override public String getStringFromItem(Item item) {
                return Integer.toString(item.getNumber());
            }
        }, 
        PARENT("parent") {
            @Override public String getStringFromItem(Item item) {
                Item p = item.getParent();
                return (p == null) ? null : p.getName();
            }           
        };

        final private String name;
        ItemKey(String name) { this.name = name; }
        public String getName() { return this.name; }
        abstract public String getStringFromItem(Item item);

        static private ItemKey[] columns = { NAME, NUMBER, PARENT }; 
        static public ItemKey[] getColumns() { return columns; }
    }
    static public class ItemTableFormat implements TableFormat<Item> {
        @Override public int getColumnCount() { 
            return ItemKey.getColumns().length; 
        }
        @Override public String getColumnName(int col) { 
            return ItemKey.getColumns()[col].getName(); 
        }
        @Override public Object getColumnValue(Item item, int col) {
            return ItemKey.getColumns()[col].getStringFromItem(item); 
        }       
    }

    static class Item {
        final private String name;
        final private int number;
        final private Item parent;

        private Item(String name, int number, Item parent) { 
            this.name=name; this.number=number; this.parent=parent;
        }
        static public Item create(String name, int number, Item parent) { 
            return new Item(name, number, parent); 
        }

        public String getName() { return this.name; }
        public int getNumber() { return this.number; }
        public Item getParent() { return this.parent; }
    }

    static public void main(String[] args)
    {

        EventList<Item> items = new BasicEventList<Item>();
        Item x1,x2,x3,x4;
        x1 = Item.create("foo", 1, null);
        items.add(x1);
        x2 = Item.create("bar", 2, x1);
        items.add(x2);
        x3 = Item.create("baz", 1, x1);
        items.add(x3);
        x4 = Item.create("quux", 4, x2);
        items.add(x4);
        items.add(Item.create("wham", 3, x3));
        items.add(Item.create("blam", 11, x3));
        items.add(Item.create("shazaam", 20, x3));
        items.add(Item.create("August", 8, x4));
        items.add(Item.create("September", 9, x4));
        items.add(Item.create("October", 10, x4));
        items.add(Item.create("November", 11, x4));
        items.add(Item.create("December", 12, x4));

        EventList<Item> sortedItems = new SortedList<Item>(items, null);
        final EventList<Item> displayList = sortedItems;
        doit(new JTable(), "JTable cell renderer", displayList);
        doit(new JXTable(), "JXTable cell renderer", displayList);
    }

    static public void doit(JTable table, String title, 
       final EventList<Item> displayList)
    {
        TableFormat<Item> tf = new ItemTableFormat();
        EventTableModel<Item> etm = 
            new EventTableModel<Item>(displayList, tf);

        table.setModel(etm);    
        if (table instanceof JXTable)
        {
            ((JXTable)table).setColumnControlVisible(true);
        }
        TableColumnModel tcm = table.getColumnModel();
        final Color selectedGreen = new Color(128, 255, 128); 
        final Color unselectedGreen =   new Color(224, 255, 224); 
        TableCellRenderer tcr = new DefaultTableCellRenderer() {
            @Override public Component getTableCellRendererComponent(
                    JTable table, Object value, 
                    boolean isSelected, boolean hasFocus, 
                    int row, int column)
            {
                Component c = super.getTableCellRendererComponent(
                        table, value, isSelected, hasFocus, row, column);
                Item item = displayList.get(row);
                Color color = null;
                if (item != null && ((item.getNumber() % 2) == 0))
                {
                    color = isSelected ? selectedGreen : unselectedGreen;
                }
                if (color == null)
                {
                    color = isSelected 
                         ? table.getSelectionBackground() 
                         : table.getBackground();
                }
                c.setBackground(color);                                     
                return c;
            }
        };
        for (int i = 0; i < tcm.getColumnCount(); ++i)
        {
            tcm.getColumn(i).setCellRenderer(tcr);
        }

        JPanel panel = new JPanel();
        panel.add(new JScrollPane(table));

        JFrame frame = new JFrame(title);
        frame.getContentPane().add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.pack();
    }
}

Answer 1

I got a response from one of the SwingX folks who said that I needed to use a Highlighter (rather than a TableCellRenderer) for the renderers to behave properly.

There was a hacky workaround but he didn't recommend it.