MongoDB aggregate query to SpringDataMongoDB - mongodb

Question

I have below MongoDB aggregate query and would like to have it's equivalent SpringData Mongodb query.
MongoDB Aggregate Query :
db.response.aggregate(
// Pipeline
[
// Stage 1 : Group by Emotion & Month
{
$group: {
_id: {
emotion: "$emotion",
category: "$category"
},
count: {
$sum: 1
},
point: {
$first: '$point'
}
}
},
// Stage 2 : Total Points
{
$addFields: {
"totalPoint": {
$multiply: ["$point", "$count"]
}
}
},
// Stage3 : Group By Category - Overall Response Total & totalFeedbacks
{
$group: {
_id: '$_id.category',
totalFeedbacks: {
$sum: "$count"
},
overallResponseTotal: {
$sum: "$totalPoint"
}
}
},
// Stage4 - Overall Response Total & totalFeedbacks
{
$project: {
_id: 1,
overallResponseTotal: '$overallResponseTotal',
maxTotalFrom: {
"$multiply": ["$totalFeedbacks", 3.0]
},
percent: {
"$multiply": [{
"$divide": ["$overallResponseTotal", "$maxTotalFrom"]
}, 100.0]
}
}
},
// Stage4 - Percentage Monthwise
{
$project: {
_id: 1,
overallResponseTotal: 1,
maxTotalFrom: 1,
percent: {
"$multiply": [{
"$divide": ["$overallResponseTotal", "$maxTotalFrom"]
}, 100.0]
}
}
}
]
);
I have tried it's equivalent in Spring Data but got stuck at Stage 2 on how to convert "$addFields" to java code. Though I search about it on multiple sites but couldn't find anything useful. Please see my equivalent java code for Stage 1.
//Stage 1 -Group By Emotion and Category and return it's count
GroupOperation groupEmotionAndCategory = Aggregation.group("emotion","category").count().as("count").first("point")
.as("point");
Aggregation aggregation = Aggregation.newAggregation(groupEmotionAndCategory);
AggregationResults<CategoryWiseEmotion> output = mongoTemplate.aggregate(aggregation, Response.class, CategoryWiseEmotion.class);
Any helps will be highly appreciated.

Answer 1

$addFields is not yet supported by Spring Data Mongodb.
One workaround is to pass the raw aggregation pipeline to Spring.
But since you have a limited number of fields after stage 1, you could also downgrade stage 2 to a projection:
{
$project: {
// _id is included by default
"count" : 1, // include count
"point" : 1, // include point
"totalPoint": {
$multiply: ["$point", "$count"] // compute totalPoint
}
}
}
I haven't tested it myself, but this projection should translate to something like:
ProjectionOperation p = project("count", "point").and("point").multiply(Fields.field("count")).as("totalPoint");
Then you can translate stage 3, 4 and 5 similarly and pass the whole pipeline to Aggregation.aggregate().