MongoDB aggregate query to java code

Question

I am trying to convert mongoDB query to Javacode, but it is returning proper values in mongo, but when running in java code it is not returning proper values for count (it is returning proper machineID, errorID but count as null, instead count should return number of records).

Mongo driver name

mongo-java-driver-3.3.0.jar

MongoDB query

 db.getCollection('collectionName').aggregate([
    {"$match" : {"machineID": {"$in": ["1","10"]} , "errorID" : "error5"}},
    {"$group" : {_id : {machineID : "$machineID", errorID : "$errorID"}, count : {$sum  : 1} } },
    {$project : {machineID : "$_id.machineID", errorID : "$_id.errorID", count : "$count", _id : 0}}
])

Javacode:

AggregateIterable<Document> resultset =dbCollection.aggregate(Arrays.asList(
                new Document("$group", new Document("_id", new BasicDBObject("machineID", "$machineID").append("errorID","$errorID").append("count", new BasicDBObject("$sum",1)))),
                new Document("$project", new Document("machineID", "$_id.machineID").append("errorID", "$_id.errorID").append("count", "$count").append("_id", 0))));

Returning values

machine ID -> 100
errorID  -> error3
count  -> null

Neil Lunn · Accepted Answer · 2017-06-13 07:31:11Z

3

It helps if you try to keep the same sort of structure to see in JSON format examples:

AggregateIterable<Document> resultset =dbCollection.aggregate(Arrays.asList(
  new Document("$match",
    new Document("machineID", new Document("$in", Arrays.asList("1","10")))
      .append("errorID", "error5")
  ),

  new Document("$group", 
    new Document("_id", 
      new Document("machineID", "$machineID").append("errorID","$errorID")
    ).append("count", new Document("$sum",1))
  ),

  new Document("$project", 
    new Document("machineID", "$_id.machineID")
      .append("errorID", "$_id.errorID")
      .append("count", "$count")
      .append("_id", 0)
  )
));

answered Jun 13, 2017 at 7:31

Neil Lunn

151k36 gold badges356 silver badges327 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

MongoDB aggregate query to java code

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related