/*
     ScrollStatus.java
       Optional parameters: message, width
       Default values:
         message = "Isn't scrolling text in the status line annoying? "
         width = 36
      Example usage:
       <applet code="ScrollStatus.class"
           width=0 height=0>
       <param name="message" value="Hello World!">
       <param name="width" value="24">
       </applet>
*/
import java.util.*;
import java.applet.Applet;

public class ScrollStatus extends Applet implements Runnable {
    Thread thread;
    String message;
    StringBuffer buffer;
    int at;
    int width;

    public void init(){
       message = getParameter("message");
       if(message == null)
         message = " Isn't scrolling text in the status line annoying? ";

       String ws = getParameter("width");
       if(ws == null) {
           width = 36;
       }
       else{
           width = Integer.valueOf(ws).intValue();
       }
       if(width < 5 || width > 180) {
         width = 36;
       }

       buffer = new StringBuffer(width);
       buffer.setLength(width);
       at = 0;

       if(message.length() < width) {
         char buf[] = new char[width];
         for(int i = 0; i < width; ++i) {
            buf[i] = ' ';
         }
         message.getChars
            (0, message.length(), buf, (width - message.length()) / 2);
         message = new String(buf);
       }
    }

    public void start(){
       thread = new Thread(this);
       thread.start();
    }

    public void stop(){
       thread.stop();
    }

    public void scroll(){
       int ml = message.length();
       int k = at;
       for(int i = 0; i < width; ++i, ++k){
          if(k >= ml) {
            k = 0;
          }
          buffer.setCharAt(i, message.charAt(k));
       }
       getAppletContext().showStatus(buffer.toString());
       at++;
       if(at >= ml) {
           at = 0;
       }
    }

    public void run(){
      while(true){
          scroll();
           try{
              Thread.sleep(25); // wait 25 ms
           }
           catch(InterruptedException e){
               break;
           }
      }
    }
 }