Class used to iterate N items as if they were shuffled.

Shuffle.java

public class Shuffle
{

    public int n;
    public int[] index;
    public long seed;

    public Shuffle( int size )
    {
        this( System.currentTimeMillis(), size );
    }

    public Shuffle( long seed, int size )
    {
        this.seed = seed;
        this.index = new int[size];
        this.n = size;
        for ( int i = 0; i < size; i++ )
        {
            this.index[i] = i;
        }
    }

    public void reset()
    {
        n = index.length;
    }

    public int next()
    {
        seed ^= (seed << 21);
        seed ^= (seed >>> 35);
        seed ^= (seed << 4);

        int relativeIndex = (int)(Math.abs( seed ) % n);
        int actualIndex = index[relativeIndex];

        index[relativeIndex] = index[--n];
        index[n] = actualIndex;

        return actualIndex;
    }

}

ShuffleTest.java

public class ShuffleTest
{
  
  public static void main(String[] args) 
  {
    Shuffle shuffle = new Shuffle( 10 );
    
    // prints out 0 through 9
    for (int i = 0; i < 10; i++) {
      System.out.print( shuffle.next() );
      System.out.print( " " );
    }
    System.out.println();
    
    shuffle.reset();
    
    for (int i = 0; i < 10; i++) {
      System.out.print( shuffle.next() );
      System.out.print( " " );
    }
    System.out.println();
    
    shuffle.reset();
    
    for (int i = 0; i < 10; i++) {
      System.out.print( shuffle.next() );
      System.out.print( " " );
    }
    System.out.println();
  }
}