The argument isSelected in the getTableCellRendererComponent indicates if the component is selected or not. In your code you are just re-assigning a value to it. What you need to do is change your renderer selection based on the value which you get.
In pseudo code
*Visual indication is usually achieved by tweaking the background/foreground colors, or calling a setSelected(boolean) on the renderer component
Can you provide me a demo code?
Did you check the link I had provided earlier?