Options for Working with Nulls

The Search API supports using the presence of a null as search criteria.

myQuery.addCriteria(cache.getAttribute("middle_name").isNull());

It also supports using the absence of a null as search criteria:

myQuery.addCriteria(cache.getAttribute("middle_name").notNull());

Which is equivalent to:

myQuery.addCriteria(cache.getAttribute("middle_name").isNull().not());

BigMemory SQL also supports using the presence or absence of null as search criteria:

select * from searchable where birthDate is null
select * from searchable where birthDate is not null

Alternatively, you can call constructors to set up equivalent logic:

Criteria isNull = new IsNull("middle_name");
Criteria notNull = new NotNull("middle_name");