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


public class F7_exempel3 extends JFrame implements ActionListener {
  private JButton startKnapp;
  private JPanel nordPanel, centerPanel;

  public F7_exempel3() {
   skapaGränssnitt();
   setVisible(true);
  }


  private void skapaGränssnitt() {
    setSize(200,200);
    Container korg = getContentPane();
    korg.setLayout(new BorderLayout());

    startKnapp = new JButton("Starta utskriftstrådarna");
    startKnapp.addActionListener(this);
    
    nordPanel = new JPanel();
    nordPanel.setSize(200, 50);
    nordPanel.add(startKnapp);

    centerPanel = new JPanel();
    centerPanel.setBackground(Color.white);
       

    korg.add(nordPanel, BorderLayout.NORTH);
    korg.add(centerPanel, BorderLayout.CENTER);
  
    setDefaultCloseOperation(EXIT_ON_CLOSE);
  }

  
 
  public void actionPerformed(ActionEvent ae) {
    if(ae.getSource() == startKnapp) {
        Trad t1 = new Trad("#1", 3000, centerPanel, 20);
        Trad t2 = new Trad("#2", 1500, centerPanel, 30);
        t1.start();
        t2.start();      
      }  
  }

  

  public static void main(String[] args) {
    new F7_exempel3();
  }

}//F7_exempel3



class Trad extends Thread {
  private String trådNamn;
  private int x, y, sovTid;
  private JPanel centerPanel ;
  
  public Trad(String trådNamn, int sovTid, JPanel centerPanel, int yKoordinat) {
    this.trådNamn = trådNamn;
    this.sovTid = sovTid; 
    this.centerPanel = centerPanel;
    x = 20;
    y = yKoordinat; 
  }

  public void run() {
   skriv();

   try {
      sleep(sovTid);
    }
    catch (InterruptedException ie) {
      System.err.println("TRASSEL i " + trådNamn);
      System.err.println(ie.getMessage());
   }
   y += 40;
   skriv();  

  }

  public void skriv() {
    Graphics penna = centerPanel.getGraphics();
    penna.drawString("Hej, skriver: " + trådNamn, x, y);
    penna.dispose();
  }

}//Trad