Filter and display relevant content in Jcombobox

I am trying to create smart combobox in my swing application. It follows the keystrokes as the user types and displays only the related contents from its list. This should update if the user hits backspace and also allow the user to scroll down and select an item in the list with/without using the mouse.
A great example is the behaviour of google toolbar.  
Help me here out guys....
thanks a bunch