How to Represent Objects with Multiple Fields in the MongoDB Java Driver

Question

I'm creating an aggregation pipeline in Java using MongoDB and, of course, the MongoDB Java driver.

I've figured out how to do what I want in the Mongo Shell, but I'm not sure how to translate this into Java, particularly the whole concept of an object with commas in it, as shown below.

{$project: {sleep: {"date": 1, "hours": 1}}}

Any thoughts on the best way to do this?

Answer 1

Turns out one great way to do this is the following:

BasicDBObject project = new BasicDBObject("$project", new BasicDBObject("sleep", new BasicDBObject().append("date", 1).append("hours", 1)));

Then you can call your aggregation command as follows:

AggregationOutput output = collection.aggregate(commandOne, commandTwo, Project, CommandThree);

Hope this helps :)