A random shuffle

Question

If I want to create a continuous loop to keep on shuffling until it gets the same sequence of numbers as the original String. How do I do that?
public class MyClass
     private Object[] myArray = null;
     public static void main(String[] args)
          MyClass shuffler =     new MyClass(new String[] {"1", "2", "3", "4","5","6","7","8"});
          System.out.println(shuffler);
          shuffler.shuffle();
          System.out.println(shuffler);
          shuffler.shuffle();
          System.out.println(shuffler);
     public MyClass(Object[] anArray)
               myArray = anArray;
     private void shuffle()
               java.util.Random rnd = new java.util.Random();
               for (int n = 0; n < myArray.length; n++)
                    int j = rnd.nextInt(myArray.length);
                    Object o = myArray[j];
                    myArray[j] = myArray[n];
                    myArray[n] = o;
          public String toString()
               String s = myArray[0].toString();
               for (int j = 1; j < myArray.length; j++)
                    s += ", " + myArray[j];
          return s;
}

Answer 1

Here's a java way of handling the shuffling back to the original using cloning, the .equals method inherited from Object (and then overridden), a single instance of Random regardless of the number of decks and a little polymorphism...
Simply pass a set of parameters to represent the deck. IE
java MyClass A B C D
and it'll shuffle them until a shuffle results in the original list again. Note it's non-deterministic since the shuffle is randomised...
import java.util.Random;
public class MyClass {
  private static final Random generator = new Random();
  private Object[] contents;
  public MyClass(Object[] contents) {
    this.contents = (Object[]) contents.clone();
  public void shuffle() {
    for(int j = 0, k = contents.length; j < k; j++) {
      int r = generator.nextInt(k);
      Object o = contents[j];
      contents[j] = contents[r];
      contents[r] = o;
  public int getSize() {
    return contents.length;
  public Object get(int index) {
    return contents[index];
  public boolean equals(Object object) {
    boolean result;
    if(object instanceof MyClass) {
      result = equals((MyClass) object);
    else if(object instanceof Object[]) {
      result = equals((Object[]) object);
    else result = false;
    return result;
  private boolean equals(MyClass object) {
    boolean result;
    if(getSize() == object.getSize()) {
      result = true;
      for(int j = 0, k = getSize(); j < k; j++) {
        Object o1 = get(j);
        Object o2 = object.get(j);
        if(o1 != o2 && (o1 == null || !o1.equals(o2))) {
          result = false;
          break;
    else result = false;
    return result;
  private boolean equals(Object[] object) {
    boolean result;
    if(getSize() == object.length) {
      result = true;
      for(int j = 0, k = getSize(); j < k; j++) {
        Object o1 = get(j);
        Object o2 = object[j];
        if(o1 != o2 && (o1 == null || !o1.equals(o2))) {
          result = false;
          break;
    else result = false;
    return result;
  public String toString() {
    String result;
    if(contents.length == 0) result = "";
    else {
      StringBuffer sb = new StringBuffer();
      sb.append(contents[0]);
      for(int j = 1; j < contents.length; j++) {
        sb.append(", ").append(contents[j]);
      result = sb.toString();
    return result;
  public static void main(String[] args) {
    MyClass shuffler = new MyClass(args);
    System.out.println(shuffler);
    int j = 0;
    do {
      shuffler.shuffle();
      j++;
    } while(!shuffler.equals(args));
    System.out.print(++j);
    System.out.println(" shuffles before returning to original.");
}Hope this helps
PS: Don't forget the dukes in this and the other thread - you can't get 'em back so you might as well reward people...
Talden