Aggregation query to get size of list

[Vaishnavi Manjunath]

Hi, 

    I am trying to count the number of elements in a list of each document in a collection, similar to below example. (https://docs.mongodb.com/manual/reference/operator/aggregation/size/#exp._S_size)

I am unable to arrive at an equivalent morphia query to achieve the same.

Any help in this regard would be greatly appreciated.

Thanks,

db.inventory.aggregate(
   [
      {
         $project: {
            item: 1,
            numberOfColors: { $size: "$colors" }
         }
      }
   ]
)