Question

I have a use case where I need to get list of Objects from mongo based off a query. But, to improve performance I am adding Pagination.
So, for first call I get list of say 10 Objects, in next I need 10 more. But I cannot use offset and pageSize directly because the first 10 objects displayed on the page may have been modified [ deleted ].

Solution is to find Object Id of last object passed and retrieve next 10 objects after that ObjectId.

Please help how to efficiently do it using Morphia mongo.

Answer 1

Using morphia you can do this by the following command.

datastore.find(YourClass.class).field(id).smallerThan(lastId).limit(10).order("-ts");

Since you are querying for retrieving the items after the last retrieved id, you won’t be bothered to deal with deleted items.