Fluent MongoDB queries from Java

MongoDB is doing great, firmly holding a prestigious #5 on the db-engines ranking site. It means that we, developers, are using it a lot.

When looking on the official driver API, we can see an effort to make an API as fluent as possible:

collection.find(and(gte("stars", 2), lt("stars", 5), eq("categories", "Bakery")));

Yet, there are many issues:

• All fields are Strings without auto completion.
• No type safety on operators (Is stars a number?! Is categories a collection (?!) of Strings or …?!).
• Do we really like using gte for >= ?! I mean, is it easy to read and understand this expression?
• And finally, when the schema changes, we are back to 80' with find-replace…

There is a simple and effective solution to those issues — FluentMongo, which adds the missing ingredient to the API — type safety and Java integration. It lets you use normal Java to write filters, projections, updates, sorts and indexes. For example:

collection.find(builder.filter(r -> r.getStars() >= 2 && r.getStars() < 5 &&
                                    r.getCategories().contains("Bakery")));

You can be both productive with MongoDB and write a maintainable code now!