public class PagedDataSourceConsumer {
  private PagedDataSource pagedDataSource;
  public void consume() {
    List<Entity> entities;
    Paging nextPage = Paging.firstPage();
    for(entities = pagedDataSource.getEntities(nextPage); !entities.isEmpty(); entities = pagedDataSource.getEntities(nextPage)) {
      for(Entity entity: entities) {
        //doStuff
      }
      nextPage = nextPage.next();
    }
  }
}