//********************************************************************
//  DrawPolylinePanel.java       Programming with Alice and Java
//
//  Solution to Programming Project 8.9
//********************************************************************

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

public class DrawPolylinePanel extends JPanel
{
   int[] xPoints, yPoints;
   int numPoints;

   //-----------------------------------------------------------------
   //  Sets up the panel. Assumes there is no more than 100
   //  line segements in the polyline.
   //-----------------------------------------------------------------
   public DrawPolylinePanel ()
   {

      setBackground (Color.black);
      xPoints = new int [100];
      yPoints = new int [100];
      numPoints = 0;
      addMouseListener (new MouseClickListener());

      Button clearButton = new Button("Clear");
      clearButton.addActionListener(new ButtonListener());
      add(clearButton);
   }

   //-----------------------------------------------------------------
   //  Draws the polyline
   //-----------------------------------------------------------------
   public void paintComponent (Graphics page)
   {
      super.paintComponent(page);
      page.setColor (Color.green);
      page.drawPolyline (xPoints, yPoints, numPoints);
   }

   //*****************************************************************
   //  Represents the listener for the mouse clicks
   //*****************************************************************
   private class MouseClickListener extends MouseAdapter
   {
      //-----------------------------------------------------------------
      //  Captures the end of the new line to add to the polygon.
      //-----------------------------------------------------------------
      public void mouseClicked (MouseEvent event)
      {
         xPoints [numPoints] = event.getX ();
         yPoints [numPoints] = event.getY ();
         numPoints++;
         repaint ();
      }
   }

   //*****************************************************************
   //  Represents the listener for the clear button
   //*****************************************************************
  class ButtonListener implements ActionListener
   {
      public void actionPerformed (ActionEvent event)
      {
         numPoints = 0;
         repaint();
      }
   }
}