How to use DateOperators in Spring Mongo Data aggregation - mongodb

Question

We have an aggregation pipeline setup in Spring Data Mongo like so:
MatchOperation matchStage = ...
Fields groupingFields = Fields.fields();
groupingFields.and(name1, target1);
groupingFields.and(name2, target2);
...
GroupOperation groupStage = Aggregation.group(groupingFields);
List<AggregationOperation> aggStages = new ArrayList<>();
aggStages.add(matchStage);
aggStages.add(groupStage);
Aggregation aggregation = Aggregation.newAggregation(aggStages);
Now, we want to be able to use aggregation over dates using Date operators in mongodb. This is fairly straightforward in mongodb, example below:
db.getCollection('Collection').aggregate([
{"$match": {"state": "XY"}},
{"$group": {
"_id": {
"city": "$city",
"dayOfYear": {"$dayOfYear": "$date"}
},
"totalProfit": {"$sum": "$profit"}
}}
])
My question is, how can I use the $dayOfYear operator in the Spring pipeline we have. Spring has support for DateOperators like DateOperators.DayOfWeek etc. but I am unable to incorporate it into the pipeline as we have it. How do I modify the groupStage so I can group by various date related parts as required?

Answer 1

For some operation I used to follow Bson document styles
#Autowired
private MongoTemplate mongoTemplate;
public List<Object> test() {
Aggregation aggregation = Aggregation.newAggregation(
match(Criteria.where("state").is("XY"))
p-> new Document("$group",
new Document("_id",
new Document("city","$city")
.append("dayOfYear",
new Document("$dayOfYear", "$date")
)
).append("totalProfit",
new Document("$sum","$$profit")
)
)
).withOptions(AggregationOptions.builder().allowDiskUse(Boolean.TRUE).build());
return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(YOUR_COLLECTION.class), Object.class).getMappedResults();
}
This should work, if the above aggregation you posted is working. You can refer Trick to convert.
I haven't tried DateOperator yet. But I'm curious how does it work. I will update if I get to know about it. Until then you have no blockers