Spring mongoDB aggregation group on date minute subset - spring

Question

I'm running Spring 2.2.7 with spring-data-mongodb.
I've an entity called BaseSample stored in a samples MongoDb collection and I want to group records by minute from the created date and getting the average value collected. I don't know how to use the DateOperators.Minute in the group aggregation operation.
detailed explanation
#Data
#Document(collection = "samples")
#EqualsAndHashCode
public class BaseSample extends Message {
private float value;
private UdcUnitEnum unit;
private float accuracy;
public LocalDateTime recorded;
}
that extends a Message class
#Data
#EqualsAndHashCode
public class Message {
#Indexed
private String sensorUuId;
#Indexed
private String fieldUuId;
#Indexed
private String baseStationUuId;
#Indexed
private Date created;
}
on which I want to apply this query
db.samples.aggregate ([
{
$match: {
$and : [ {fieldUuId:"BS1F1"}, {unit: "DGC"}, {created : {$gte : ISODate("2020-05-30T17:00:00.0Z")}}, {created : {$lt : ISODate("2020-05-30T17:15:00.0Z")}}]
}
},
{
$group: {
_id : { $minute : "$created"},
date : {$first : {$dateToString:{date: "$created", format:"%Y-%m-%d"}}},
time : {$first : {$dateToString:{date: "$created", format:"%H:%M"}}},
unit : {$first : "$unit"},
data : { $avg : "$value"}
}
},
{
$sort: {date:1, time:1}
}
])
on the samples collection (exerpt)
{
"_id" : ObjectId("5ed296150af58a1c60c4f154"),
"value" : 90.85242462158203,
"unit" : "HPA",
"accuracy" : 0.6498473286628723,
"recorded" : ISODate("2020-05-30T17:21:25.850Z"),
"sensorUuId" : "458f0ffd-13f9-466d-81a1-8d2e1c808da9",
"fieldUuId" : "BS1F2",
"baseStationUuId" : "BS1",
"created" : ISODate("2020-05-30T17:21:25.777Z"),
"_class" : "org.open_si.udc_common.models.BaseSample"
}
{
"_id" : ObjectId("5ed296150af58a1c60c4f155"),
"value" : 40.84038162231445,
"unit" : "HPA",
"accuracy" : 0.030185099691152573,
"recorded" : ISODate("2020-05-30T17:21:25.950Z"),
"sensorUuId" : "b396264f-fcd5-4653-8ac8-358ca3a4cb87",
"fieldUuId" : "BS2F3",
"baseStationUuId" : "BS2",
"created" : ISODate("2020-05-30T17:21:25.868Z"),
"_class" : "org.open_si.udc_common.models.BaseSample"
}
I coded the following method to get the average value of samples grouped per minute for a selected unit type (degree, ...) in a selected field (sensors logical group)
public List aggregateFromField(String fieldUuId, UdcUnitEnum unit, LocalDateTime from, LocalDateTime to, Optional pageNumber, Optional pageSize){
Pageable paging = new PagingHelper(pageNumber, pageSize).getPaging();
MatchOperation fieldMatch = Aggregation.match(Criteria.where("fieldUuId").is(fieldUuId));
MatchOperation unitMatch = Aggregation.match(Criteria.where("unit").is(unit.name()));
MatchOperation fromDateMatch = Aggregation.match(Criteria.where("created").gte(from));
MatchOperation toDateMatch = Aggregation.match(Criteria.where("created").lt(to));
DateOperators.Minute minute = DateOperators.Minute.minuteOf("created");
GroupOperation group = Aggregation.group("created")
.first("created").as("date")
.first("created").as("time")
.first("unit").as("unit")
.avg("value").as("avg")
;
SortOperation sort = Aggregation.sort(Sort.by(Sort.Direction.ASC, "$date")).and(Sort.by(Sort.Direction.ASC, "$time"));
SkipOperation skip = Aggregation.skip(paging.getOffset());
LimitOperation limit = Aggregation.limit(paging.getPageSize());
Aggregation agg = Aggregation.newAggregation(
fieldMatch,
unitMatch,
fromDateMatch,
toDateMatch,
group,
sort,
skip,
limit
);
AggregationResults<SampleAggregationResult> results = mongoTemplate.aggregate(agg, mongoTemplate.getCollectionName(BaseSample.class), SampleAggregationResult.class);
return results.getMappedResults();
}
this result class is :
#Data
public class SampleAggregationResult {
private String date;
private String time;
private String unit;
private float data;
}
Any idea on using the DateOperators.Minute type in the agrregation group operation ?
thnaks in advance.