java实现打字机效果的程序

import java.applet.*;
import java.awt.*;
import java.io.*;
import java.net.URL;
import java.util.*;
public class Typewriter4 extends Applet implements Runnable
{
    AudioClip hit, cr, ding ;
    boolean alreadyRun = false,
            soundOn = false,
            loop = false;
    Color bgColor = Color.lightGray,
          textColor = Color.black ;
    Font font ;
    Image offScreen, background ;
    int width, height,
        currentline = 0,
        currentword = 0,
        currentletter = 0,
        depth = 0,
        margin = 0,
        cycles = 0,
        step = 0,
        pause = 0,
        speed = 0,
        update = 0,
        linecount = 0 ;
    long lastread = 0;
    MediaTracker mt ;
    String soundactivation, text, textfile, target ;
    Thread woohoo = null;
    URL hotlink = null;
    Vector lines = null;
    public Typewriter4()
    {
        alreadyRun = false;
        soundOn = false;
        loop = true;
        soundactivation = "enter";
    }
    public void buildLines()
    {
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