Consider converters for OptionalInt, OptionalLong, and OptionalDouble

[mp911de]

Since primitive null values are not emitted as query result (see #469), we should consider adding support for optional primitive projections such as OptionalInt. These types allow reasoning about the target type and their value may be absent while still emitting a result object. This may be required when the result order matters.

interface MyRepository extends ReactiveCrudRepository<MyEntity, Integer> {

    @Query("SELECT age FROM my_table ORDER BY first_name")
    Flux<OptionalInt> findMaxAge();
}

[vasantteja]

Can you please assign this issue to me?

[mp911de]

For the time being, this ticket should be probably handled in Spring Data Commons to enable other store modules to consume results as OptionalInt etc.