MongoDB $aggregate $push multiple fields in Java Spring Data

Question

I have a mongo aggregate group query:

db.wizard.aggregate(
{
$group: {
    _id: \"$title\",
    versions: { $push: {version:\"$version\", author:\"$author\",         


        

Answer 1

In the new version spring-data-mongodb:2.x.x the AggregationOperation need to return Document instead of DBObject, so the updated class will be:

import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;
import org.bson.Document;
import org.springframework.data.mongodb.core.aggregation.AggregationOperation;
import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;

public class GenericAggregationOperation implements AggregationOperation {

    private String operator;
    private DBObject query;

    public GenericAggregationOperation(String operator, DBObject query) {
        this.operator = operator;
        this.query = query;
    }

    public GenericAggregationOperation(String operator, String query) {
        this(operator, BasicDBObject.parse(query));
    }

    @Override
    public Document toDocument(AggregationOperationContext context) {
        return new Document(operator, query);
    }
}

Plus to make it easier to be used I'll add utility interface (java 8+, for java 7 or lower you can convert this to class utils instead):

import com.mongodb.DBObject;
import org.springframework.data.mongodb.core.aggregation.AggregationOperation;

public interface GenericAggregationUtils {

    static AggregationOperation aggregate(String operation, String query) {
        return new GenericAggregationOperation(operation, query);
    }

    static AggregationOperation aggregate(String operation, DBObject query) {
        return new GenericAggregationOperation(operation, query);
    }

}

And then we can static import the interface into our class:

import static com.example.mongodb.aggregation.GenericAggregationUtils.*;

And use it in the aggregation pipeline together with other spring data AggregationOperation like this:

Aggregation aggregation = newAggregation(YourDocCollection.class,
    aggregate("$group", "{ \"_id\": \"$title\", \"versions\": { \"$push\": { \"version\":\"$version\", \"author\":\"$author\", \"dateAdded\":\"$dateAdded\"}} }"),
    sort(Sort.Direction.ASC, "title"),
    ...
);