Query for collection equality in MultiValueAttribute

[Marcin Kruglik]

Hi,

When I have a collection of Cars where one attribute is a multi value attribute, let say Features.

So I added Cars with bellow Features to my collection:
Car1 { "Alloy wheels", "AC", "leather seats"}

Car2 { "Alloy wheels"}

Car3 {"Alloy wheels", "DAB radio"}

I need to write a query which will return only Car1. Something like Query.equals(featuresAttribute, Collection.of("Alloy wheels", "AC", "leather seat") but only query I can find, which works with MultiValueAttributes is in() or eq() which in my case would return all cars (includes at least one element).

I think this is a common use case, but can't find anything about it. Any leads would be appreciated.

Cheers

Marcin

[Marcin Kruglik]

Just to add,

My query shouldnt also match Car4 { "Alloy wheels", "AC", "leather seats", "sport  exhaust"}.

Marcin

[Niall]

Sorry for the delay.
This is a good question.

The best way to solve this is probably to define another attribute NUM_FEATURES which returns the number of features, and to combine that with an in() query.

For example:
Collection<String> exactFeaturesRequired = Arrays.asList("a", "b", "c");

Query<Car> query = and(in(Car.FEATURES, exactFeaturesRequired), equal(Car.NUM_FEATURES, exactFeaturesRequired.size()));

Hope that helps,
Niall