import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;

public class TimerSkeleton
{
	public static void main(String[] args)
	{
		JFrame f=new JFrame();
		f.setSize(800,800);
    	f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	    TimerPanel panel = new TimerPanel();
      	f.add(panel);
      	f.setVisible(true);
	}
	
	public static class TimerPanel extends JPanel implements ActionListener
	{
		private Timer t;
		// private int variables to represent the object(s)
		private int[] x, y, dx, dy;
		private int num;
		private Random gen;
		
		public TimerPanel()
		{
			t=new Timer(10,this);
			gen=new Random();
			// set up object(s) to move here
			x=new int[25];
			y=new int[25];
			dx=new int[25];
			dy=new int[25];
			num=25;
			for(int i=0;i<num;i++)
			{
				x[i]=gen.nextInt(780)+20;
				y[i]=gen.nextInt(730)+20;
				dx[i]=gen.nextInt(5)-2;
				dy[i]=gen.nextInt(5)-2;
			}
			t.start();
		}
		
		public void actionPerformed(ActionEvent e)
		{
			// move object(s) here
			for(int i=0;i<num;i++)
			{
				x[i]=x[i]+dx[i];
				y[i]=y[i]+dy[i];
				if(y[i]<20) y[i]=730;
				else if(y[i]>730) y[i]=20;
				if(x[i]<20) x[i]=780;
				else if(x[i]>780) x[i]=20;
				for(int j=0;j<num&&i!=j;j++)
					if(Math.abs(x[i]-x[j])<20&&Math.abs(y[i]-y[j])<20)
					{
						dx[i]=gen.nextInt(5)-2;
						dy[i]=gen.nextInt(5)-2;
						dx[j]=gen.nextInt(5)-2;
						dy[j]=gen.nextInt(5)-2;
					}
			}
			repaint();
		}
		
		public void paintComponent(Graphics g)
		{
			// draw object(s) here
			super.paintComponent(g);
			for(int i=0;i<num;i++)
			{
				g.setColor(Color.blue);
				g.fillOval(x[i],y[i],20,20);
			}
		}
	}
}