public List<ProductHierarchy> createHierarchy(List<Product> allProducts, Product p) {
    List<ProductHierarchy> SubHierarchy = new ArrayList<ProductHierarchy>();
    for (Product prod : allProducts) {
      if (prod.getParentID() == this.product.getID()) {
        SubHierarchy.add(new ProductHierarchy(allProducts, prod));
      }
    }

    return SubHierarchy;
  }