High CPU issue due to table.setForeground() in JTable renderer

Question

Hi,
I have a JTable with a renderer to set the text color for the row if certain conditions exist.
The code below "works" although I have two issues:-
1. The command "table.setForeground(Color.BLUE);" in the code below causes 50% CPU utilisation (Win XP, service pack 3). Very strange and consistent - tested on two different PCs.
2. At times, the first column below the intended column changes color. The rest of the intended column has color set correctly.
I'm using beans binding with the table concerned so can't post the table model - I believe the binding effectively has it's own model.
Be greatful for any insight as it seems v. strange.....
Thanks,
</code>
        masterTable.setDefaultRenderer(String.class, textColour);
    TableCellRenderer textColour = new TableCellRenderer() {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            MailingList mL = (MailingList) queryList.get((table.convertRowIndexToModel(row)));
            table.setForeground(Color.BLACK);
            if (mL.getApplicationAppId() != null) {
                if (mL.getApplicationAppId().getSembookingsCollection() != null) {
                    Collection sB = mL.getApplicationAppId().getSembookingsCollection();
                    if (!sB.isEmpty()) {
//                        table.setForeground(Color.BLUE);  //this line causes 50% CPU utilisation ???
            TableCellRenderer delegate = table.getDefaultRenderer(Object.class);
            return delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
{code}                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

Here's my latest attempt, but still some questions and issues.
I create a textColour class and this time attempt to set the colour on the component rather than the whole table in a similar fashion to the prepareRenderer(&hellip;) method.
This appears to work and the CPU is no longer 50% utilisation.
However, I still have the following questions/issues/observations:-
1. I now need to set a renderer for each type of data. Perhaps this is the way it "should" be done. For example, I need to add " masterTable.setDefaultRenderer(Date.class, new textColour());" and then reformat the dates otherwise they don't change color. Would have been nice to set the colour for the whole row BUT can't see how as I can't use the preparedRenderer method?
2. Perhaps related to the above, as I now return "comp", I don't call the default tableRenderer : i.e. " return delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);" {code} Is there a cleaner/"better" way to do this? If I do return the above, I don't see any colour change as my changed "comp" is replaced by returning the component from the default call above.
3. Persumably I'm no longer in a loop as CPU is "normal" and no where near 50% (more like 0%). I still set the row to be BLACK first otherwise all rows change colour (BLUE) but looks like the row isn't rendered until the component is returned.
4. I no longer have the second issue of colour being incorrect for the first column of one row. So that's good!
Here's the latest ver of the code.......
Thanks,
{code:java}
        masterTable.setDefaultRenderer(String.class, new textColour());
        masterTable.setDefaultRenderer(Date.class, new textColour());
      public class textColour extends DefaultTableCellRenderer {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            MailingList mL = (MailingList) queryList.get((table.convertRowIndexToModel(row)));
            Component comp = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            if (value instanceof java.util.Date) {
                this.setText(shortDf.format((Date) value));
            comp.setForeground(Color.BLACK);
            if (mL.getApplicationAppId() != null) {
                if (mL.getApplicationAppId().getSembookingsCollection() != null) {
                    Collection sB = mL.getApplicationAppId().getSembookingsCollection();
                    if (!sB.isEmpty()) {
                        comp.setForeground(Color.BLUE);
//            TableCellRenderer delegate = table.getDefaultRenderer(Object.class);
//            return delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            return comp;
{code}