Mongo DB to filter a Document if the field of an array has same value across all elements using mongo java driver

Question

I need to fetch the document from the db, data is as below

{
   "systemName": "ABC",
    "systemUsageAttrs" : [
                          {
                           "cpuUsage": 30,
                           "memUsage": 40,
                           "isActive": false
                           },
                           {
                           "cpuUsage": 88.2,
                           "memUsage": 33.5,
                           "isActive": false
                           }
                         ]
},
{
   "systemName": "DEF",
    "systemUsageAttrs" : [
                          {
                           "cpuUsage": 30,
                           "memUsage": 40,
                           "isActive": false
                           },
                           {
                           "cpuUsage": 88.2,
                           "memUsage": 33.5,
                           "isActive": true
                           }
                         ]
},
{
   "systemName": "GHI",
    "systemUsageAttrs" : [
                          {
                           "cpuUsage": 30,
                           "memUsage": 40,
                           "isActive": true
                           },
                           {
                           "cpuUsage": 88.2,
                           "memUsage": 33.5,
                           "isActive": true
                           }
                         ]
}

I have used below piece of code, but it returns 2 documents instead of one.

List<Document> systemDetailsAL = sysUsageDetailsColl.aggregate(
                asList(
                        unwind("$systemUsageAttrs"),
                        match(eq("systemUsageAttrs.isActive",false)),
                        group("$_id", Accumulators.first("systemName","$systemName"),
                                Accumulators.push("systemUsageAttrs", "$systemUsageAttrs")),
                        project(Projections.fields(Projections.excludeId()))
                        
                        )
                ).into(new ArrayList<Document>());

Above code also provides the document which has isActive:false for one of the elements in the array.

Expected output is Document with systemName: ABC, since it has isActive:false in all the elements of array.

Any help/pointers appreciated.

Answer 1

Play

db.collection.find({
  "systemUsageAttrs": {
    "$not": {
      "$elemMatch": {
        "isActive": {
          $nin: [
            false
          ]
        }
      }
    }
  }
})

$not excludes documents which are identified by $elemMatch where value is not false.

1. $elemMatch identifies documents where isActive not in false
2. $not excludes that documents.

You can convert this query to java compatible.

Problem with the code i.e query used:

1. You are doing unwind
2. Then finding all docs - it returns the first sub doc of second document
3. You are grouping again
4. It will have the second document as well because it is part of the previous pipeline.