Serial

package quickgen;



import java.io.PrintStream;

public class QuickGen
{
  private static int shortHash(CharSequence s, int start, int end)
  {
    int check = 0;

    for (int ii = start; ii < end; ii++) {
      check = check * 149 + s.charAt(ii);
    }
    return check & 0xFFFF;
  }

  public static String generate(String prefix) {
    long ts = System.currentTimeMillis();
    StringBuilder sb = new StringBuilder();

    for (int ii = 0; ii < prefix.length(); ii++)
      sb.append(String.format("%X", new Object[] { Short.valueOf((short)prefix.charAt(ii)) }));
    sb.append('-');
    sb.append(String.format("%X", new Object[] { Long.valueOf(ts) }));

    int hash = shortHash(sb, 0, sb.length());

    sb.append('-');

    String lastKeyPart = String.format("%X", new Object[] { Integer.valueOf(hash) });

    while (lastKeyPart.length() < 4) {
      lastKeyPart = new StringBuilder().append("0").append(lastKeyPart).toString();
    }

    if (lastKeyPart.length() > 4)
      lastKeyPart.substring(0, 4);
    sb.append(lastKeyPart);

    return sb.toString();
  }

  public static boolean isValid(String serial) {
    int pos = serial.lastIndexOf('-');

    if (pos < 1) {
      return false;
    }
    int checkHash;
    try
    {
      checkHash = Integer.parseInt(serial.substring(pos + 1), 16);
    } catch (Throwable x) {
      return false;
    }

    return checkHash == shortHash(serial, 0, pos);
  }

  public static void main(String[] args) {
    String s = generate("GF");
    System.out.println(s);

    s = generate("AB");
    System.out.println(s);
    s = generate("TG");
    System.out.println(s);

      s = generate("YH");
    System.out.println(s);
      s = generate("AG");
    System.out.println(s);
      s = generate("UI");
    System.out.println(s);
      s = generate("AO");
    System.out.println(s);
      s = generate("OP");
    System.out.println(s);

      s = generate("DP");
    System.out.println(s);
      s = generate("XY");
    System.out.println(s);
      s = generate("OZ");
    System.out.println(s);




  }

  public static void PrintMessage(String message)
{
    System.out.println(message);
}
}