public IEnumerable <Product> Filter(IEnumerable <Product> products, IProductSpecification specification)
{
foreach (var item in products)
{
if (specification.isSatisfied(item))
{
yield return(item);
}
}
}
public bool isSatisfied(Product p)
{
return(spec1.isSatisfied(p) && spec2.isSatisfied(p));
}