/**
* Creates a Filter from a given expression.
* @param model the Model to create the (blank node) Filter in
* @param expression the expression node (not null)
* @return a new Filter
*/
public static IFilter createFilter(SpinProcessor model, INode expression)
{
IFilter filter = (IFilter)model.CreateResource(SP.ClassFilter).As(typeof(FilterImpl));
filter.AddProperty(SP.PropertyExpression, expression);
return(filter);
}