Bitwise operator in Hibernatesearch

Hibernate Search
1

Hi everyone,

is there a way to use bitwise operator in hibernate search. For example I would like to get all the entities where value & 2 = 0.

Thank you in advance!

2

Hi,

No, I don’t think that’s possible (at least not with decent performance), even with native predicates that are not exposed in Hibernate Search.

However, if that makes sense, you can use a custom bridge to index bit values. That may be a bit wasteful, but it would work.

For example index each bit in its own field:

@GenericField
@GenericField(name = "value_bit0", valueBinder = @ValueBinderRef(type = IntegerMaskBinder.class, params = @Param("mask", "1"))
@GenericField(name = "value_bit1", valueBinder = @ValueBinderRef(type = IntegerMaskBinder.class, params = @Param("mask", "2"))
@GenericField(name = "value_bit2", valueBinder = @ValueBinderRef(type = IntegerMaskBinder.class, params = @Param("mask", "4"))
public Integer value;

public class IntegerMaskBinder implements ValueBinder { 
    @Override
    public void bind(ValueBindingContext<?> context) {
        int mask = Integer.parseInt((String) context.param("mask"));
        context.bridge( 
                Integer.class, 
                (value, context) -> value == null ? null : value % mask
        );
    }
}

Then:

List<MyEntity> hits = Search.session(entityManager).search(MyEntity.class)
        .where(f -> f.match().field("value_bit1").matching(0))
        .fetchHits(20);

There are ways to improve on this, but it all depends on the requirements.

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