import javax.swing.JFrame;
/**
   Test driver for Spiral class.
*/
public class SpiralViewer
{
   public static void main(String[] args)
   {
      JFrame frame = new JFrame();
      final int FRAME_WIDTH = 400;
      final int FRAME_HEIGHT = 400;

      frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
      frame.setTitle("SpiralViewer");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      SpiralComponent component = new SpiralComponent();
      frame.add(component);
      frame.setVisible(true);
   }
}

import javax.swing.JComponent;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Point2D;
import java.awt.geom.Line2D;

public class SpiralComponent extends JComponent
{
   public void paintComponent(Graphics g)
   {
      Graphics2D g2 = (Graphics2D) g;
      final int INITIAL_SIZE = 10;

      int size = Math.min(getWidth(), getHeight());
      SpiralGenerator gen = new SpiralGenerator(
         INITIAL_SIZE,
         new Point2D.Double(size / 2, size / 2));

      while (true)
      {
         Line2D.Double segment = gen.nextSegment();
         if (!segment.intersects(getBounds()))
            return;
         g2.draw(segment);
      }
   }
}

import java.awt.geom.Point2D;
import java.awt.geom.Line2D;

public class SpiralGenerator
{
   /**
      Creates a spiral generator.
      @param initialSize the size of the first (shortest) segment
      of the spiral, in pixels
      @param start the starting point of the spiral
   */
   public SpiralGenerator(double initialSize, Point2D.Double start)
   {
	   init = start;
	   size = initialSize;
   }

   /**
      Returns the next segment of the spiral.
      @return the next segment
   */
   public Line2D.Double nextSegment()
   {
	   Line2D.Double test = new Line2D.Double(0.0,0.0,0.0,0.0);

	   return test;
   }

   // private implementation
   private double size;
   private Point2D.Double init;

}

import java.awt.geom.Point2D;
import java.awt.geom.Line2D;

public class SpiralTester
{
   public static void main(String[] args)
   {
      SpiralGenerator gen = new SpiralGenerator(10, new Point2D.Double(100, 100));
      Line2D line = gen.nextSegment();
      System.out.println(line.getX1()); 
      System.out.println("Expected: 100");
      System.out.println(line.getY1()); 
      System.out.println("Expected: 100");
      System.out.println(line.getX2()); 
      System.out.println("Expected: 110");
      System.out.println(line.getY2()); 
      System.out.println("Expected: 100");
      line = gen.nextSegment();
      System.out.println(line.getX1()); 
      System.out.println("Expected: 110");
      System.out.println(line.getY1());
      System.out.println("Expected: 100");
      System.out.println(line.getX2());
      System.out.println("Expected: 110");
      System.out.println(line.getY2());
      System.out.println("Expected: 90");
   }
}