Capture paste action with middle mouse button

I'm working on a Linux machine, and unlike Windows, there are two clipboards, the STRG-C and STRG-V clipboards and the clipboard for highlighted text and middle-click paste.

Now I'm trying to capture the paste action because I want to validate the clipboard and prevent illegal input to the text field.

I successfully captured the standard slurry of STRG-V by:

Action action = textField.getActionMap().get("paste-from-clipboard");
textField.getActionMap().put("paste-from-clipboard", new ProxyAction(action, "paste-from-clipboard"));

and the implementation of the ProxyAction class:

    public class ProxyAction extends TextAction
    {
        private Action action;

        public ProxyAction1(Action action, String actionName)
        {
            super(actionName);
            this.action = action;
       }

       @Override
       public void actionPerformed(ActionEvent e)
       {
           action.actionPerformed(e);
       }
   }

My question is, how do I capture the linux specific middle mouse button paste? The code above doesn't get it, and the action "paste" in the jTextfield doesn't solve the problem either.