CODEWITHSUNDEEP
javamongodb
Andrelan
Andrelan

Reputation: 65

How can I code this Aggregate MongoDB query in Java?

I have this MongoDB query:

db.collection.aggregate([
  {
    $set: {
      AllSeasons: {
        $concatArrays: [
          "$Seasons",
          [ "$Last season" ],
          [ "$Last season 2" ]
        ]
      }
    }
  },
  { $set: { average: { $avg:  "$AllSeasons.goals"  } } }
])

I want to code this query in Java. I have made several attempts but I don't get an error with $concatArrays and can't resolve it.

This is what I tried:

AggregateIterable<Document> doc = coll.aggregate(Arrays.asList(
                new Document("$set", new Document("AllSeasons", new Document("$concatArrays", "[$Seasons, ['$Last season'] , ['$Last season 2']] "))),
                new Document("$set", new Document("Average", new Document("$avg", "$AllSeasons.goals")))));

So how do I code this query in Java?

Thank you so much!

Upvotes: 1

Views: 741

Answers (1)

varman
varman

Reputation: 8894

Hope the mongo query is working. And you can go with mongoTemplate

public List<Object> test(){

    Aggregation aggregation = Aggregation.newAggregation(
        a-> new Document("$set",
                new Document("AllSeasons",
                    new Document("$concatArrays",
                        Arrays.asList("$Seasons",Arrays.asList("$Last_season_1"),Arrays.asList("$Last_season_2"))
                    )
                )
        ),
        b-> new Document("$set",
                new Document("average",
                    new Document("$avg","$AllSeasons.goals")
                )
        )
    ).withOptions(AggregationOptions.builder().allowDiskUse(Boolean.TRUE).build());

    return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(YOUR_COLLECTION.class), Object.class).getMappedResults();
}

Upvotes: 2

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