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Create a ProjectionOperation with Difference with spring mongodb

 3 years ago
source link: https://stackoverflow.com/questions/46786577/create-a-projectionoperation-with-difference-with-spring-mongodb
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Create a ProjectionOperation with Difference with spring mongodb

I have an projection, whitch i have to translate to java and i get not the correct result, like in the mongo db executer with javascript. 

{
        $project: {"userId": 1, "followingAndNotFollowingBack": {
            $setDifference: ["$following", "$follower"]}}
}

until now i have in Java the following:

private static final ProjectionOperation PROJECTION_OPERATION = Aggregation.project(UserRelationships.FIELD_USER_ID)
            .and(SetOperators.SetDifference.arrayAsSet(UserRelationships.FIELD_FOLLOWING_USER_IDS)
                    .differenceTo(UserRelationships.FIELD_FOLLOWER_USER_IDS))
            .as(FOLLOWING_AND_NOT_FOLLOWED_BACK);

but i get everytime an null
did anybody see the problem?

thanks a lot


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