JDOQL - isEmpty() on variable field not working?

Question

I have a class X that has a Set of Filters. Each Filter has a Set of
elements. For this example, I'll use CommodityFilter that has a Set of
Commodities. Here is some example code of the example:
public class X {
// type: Filter
private Set filters = new HashSet();
public class CommodityFilter extends Filter {
// type: Commodity
private Set commodities = new HashSet();
public class Commodity {
private String name;
Here is my query in English:
Give me all X where the "filters" set does NOT contain a CommodityFilter
OR it contains a CommodityFilter and that CF's commodities set is empty
OR it contains a CommodityFilter and that CF's commodities set contains
comm
In JDOQL:
!filters.contains(commFilter)
|| (filters.contains(commFilter) && commFilter.commodities.isEmpty())
|| (filters.contains(commFilter) && commFilter.commodities.contains(comm))
Variable: CommodityFilter commFilter
Parameter: Commodity comm
Value: comm set to Commodity instance
When I run this query, it returns all instances of X. I did some testing
and
found that the clause "(filters.contains(commFilter) &&
commFilter.commodities.isEmpty())" always returns true, even if the
commodities Set does have entries.
This is on PostgreSQL 7.4.2 with Kodo 3.1.0.
Am I constructing this query incorrectly or structuring it improperly
somehow? Or does someone have a better idea for how it should be written?
thanks for your help,
dave

Answer 1

!filters.contains(commFilter)
|| (filters.contains(commFilter) && commFilter.commodities.isEmpty())
|| (filters.contains(commFilter) && commFilter.commodities.contains(comm))The problems might stem from the fact that you're re-constraining the
commFilter variable 3 times by using it in a contains() statement.
The first use -- "!filters.contains(commFilter)" -- is rather
meaningless, since commFilter doesn't have any criteria on it and so can
be any element of the collection. Do you mean filters.isEmpty()?
For the second and third uses, I recommend using different variables and
seeing if that makes any difference.