I\'ve got a class that implements Iterator with a ResultSet as a data member. Essentially the class looks like this:
public class A implements Iterator{
It sounds like you are stuck between either providing an inefficient implementation of hasNext or throwing an exception stating that you do not support the operation.
Unfortunately there are times when you implement an interface and you don't need all of the members. In that case I would suggest that you throw an exception in that member that you will not or cannot support and document that member on your type as an unsupported operation.