Querying

Usage

It is recommended that you use the driver’s query builders. The JacksonMongoCollection will try and serialize the fields of your query correctly using the mapper.

Queries will always return a FindIterable of the type backing the collection, and you map call any methods on that iterable freely.

Examples

Simple equality:

coll.find(Filters.eq("username", "jsmith"));

Multiple operators can be chained together:

coll.find(Filters.gte("age", 21).exists("parent"));

You can pass a filter to the returned iterable:

List<BlogPost> posts = coll.find().filter(
    Filters
        .in("tags", "mongodb", "java", "jackson")
        .is("published", true)
)
    .limt(10)
    .into(new ArrayList<>());

Sorting

MongoJack works as with standard MongoCollection iterables:

FindIterable<BlogPost> posts = coll.find().sort(Sorts.orderBy(Sorts.descending("field1"), Sorts.ascending("field2")));

Projections

If you don’t want to load the entire object, you can use projections to either include or exclude fields. Use them just as you would with FindIterable:

List<BlogPost> posts = coll.find(Filters.eq("published", true))
    .projection(Projections.include("title", "author"))
    .into(new ArrayList<>());

Serialization

MongoJack will attempt to serialise values according to the serialisation configuration of the bean. This is, however, only done on a best effort basis. In some cases it may not be possible to serialise all values, for example, when using polymorphic types or ungenercised collections.