interacting with source from an event

Newbie & Debugging Questions
#1

I have a question about swing events. In the actionPerformed() or itemStateChanged() methods, is it possible to get the source or the event, and interact with it? What I’m trying to do here is just limit how many boxes can be checked. If the user selects more than six boxes, I want that 7th box to automatically uncheck, however, I’m not sure how to refer back to it, like I’m trying to do with “source.setSelected(false);”. Obviously that doesn’t work, but I imagine there is a way to do it. Any help?

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JLottery2 extends JFrame implements ItemListener{
	JCheckBox[] numBox = new JCheckBox[30];
	int numChecked = 0;
	public JLottery2(){
		super("Lottery");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setLayout(new FlowLayout());
		for(int i = 0; i < 30; i++){
			numBox[i] = new JCheckBox(Integer.toString(i+1), false);
			add(numBox[i]);
			numBox[i].addItemListener(this);
		}
	}
	public void itemStateChanged(ItemEvent e){
		Object source = e.getItem();
		int select = e.getStateChange();
		if(select == ItemEvent.SELECTED){
			if(numChecked < 6){
				numChecked++;
			}
			else{
				source.setSelected(false);
			}
		}
		else{
			numChecked--;
		}
	}
	public static void main(String arg[]){
		JLottery2 frame = new JLottery2();
		frame.setSize(300, 400);
		frame.setVisible(true);
	}
}