code: public int getRandomInt() {
      	
          Integer newInt = null;
          do {
          	newInt = randomGenerator.nextInt();
          } while(this.previousRandomInts.contains(newInt));
          this.previousRandomInts.add(newInt);
          return newInt.intValue();
      }
docs: Generates a random integer that is unique with respect to the document.
  Will not return a number between -1 and -5 because some values in that range are invalid.
  @return A random int