Does Spring Data MongoDb support $filter array aggregations operator?

Question

I\'m trying to implement in Spring Data using MongoTemplate the following working mongoDb query:

db.answers.aggregate([
        { \"$match\" : { \"object_id\         


        

Answer 1

You can workaround this issue by providing your own AggregationExpression.

ProjectionOperation agg = Aggregation.project() //

      .and(new AggregationExpression() {

        @Override
        public DBObject toDbObject(AggregationOperationContext context) {

          DBObject filterExpression = new BasicDBObject();
          filterExpression.put("input", "$answer_list");
          filterExpression.put("as", "answer");
          filterExpression.put("cond", new BasicDBObject("$eq2", Arrays.<Object> asList("$$answer.question", 2)));

          return new BasicDBObject("$filter", filterExpression);
        }
      }).as("profile");

Answer 2

There is one more alternative using Aggregation

Aggregation aggregation = newAggregation(
                           project()
                           .and(filter("answer_list")
                           .as("answer")
                       .by(valueOf("answer.question").equalToValue(2)))
                           .as("profile"));
AggregationResults<OutputType> profile = mongoTemplate.aggregate(aggregation, InputType.class, OutputType.class);

I may not be able to answer your question correctly but I just wanted to give another approach for aggregation as there are lesser number of examples using Aggregation.

In project() you can specify keys you want in your response, as its a varargs method