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Код

import java.util.Arrays;
import java.util.Iterator;
import java.util.Random;

public class Lot<T> implements Iterable<T>
{
  private Random rnd = new Random();
  private T[] variants;

  public Lot(T... variants)
  {
    setVariants(variants);
  }

  public void setVariants(T... variants)
  {
    if(variants == null || variants.length < 2)
      throw new IllegalArgumentException("You must provide at least 2 variant");

    this.variants = variants;
  }

  public T[] getVariants()
  {
    if(variants == null)
      return null;

    T[] variantsCopy = Arrays.copyOf(variants, variants.length);
    shuffle(variantsCopy);
    return variantsCopy;
  }

  public Iterator<T> iterator()
  {
    if(variants == null)
      throw new IllegalStateException("Lot has been already thrown");

    shuffle(this.variants);
    Iterator<T> iter = new LotIterator<T>(variants);
    variants = null;
    return iter;
  }

  public void shuffle(T[] arr)
  {
    for(int i = arr.length; i > 1; i--)
      swap(arr, i - 1, rnd.nextInt(i));
  }

  private static <T> void swap(T[] arr, int i, int j)
  {
    T tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
  }

  public static void main(String[] args)
  {
    Lot<Integer> integerLot = new Lot<Integer>(1, 2, 3, 4, 5);

    System.out.println("First attempt");
    for(Integer i : integerLot)
      System.out.println(i);

    System.out.println("Second attempt");
    for(Integer i : integerLot)
      System.out.println(i);
  }

  private static class LotIterator<T> implements Iterator<T>
  {
    private T[] variants;
    private int cursor = 0;

    private LotIterator(T[] variants)
    {
      this.variants = variants;
    }

    public boolean hasNext()
    {
      return cursor < variants.length;
    }

    public T next()
    {
      T t = variants[cursor];
      cursor++;
      return t;
    }

    public void remove()
    {
      throw new UnsupportedOperationException();
    }
  }
}