What’s New

This release includes full support for the upcoming MongoDB 3.4 server release. Key new features include:

Support for Decimal128 Format

import org.bson.types.Decimal128;

The Decimal128 format supports numbers with up to 34 decimal digits (i.e. significant digits) and an exponent range of −6143 to +6144.

To create a Decimal128 number, you can use

• Decimal128.parse() with a string:

    Decimal128.parse("9.9900");
  

• new Decimal128() with a long:

    new Decimal128(10L);
  

• new Decimal128() with a java.math.BigDecimal:

    new Decimal128(new BigDecimal("4.350000"));
  

Support for Collation

import com.mongodb.client.model.Collation;

Collation allows users to specify language-specific rules for string comparison. Use the Collation.builder() to create the Collation object. For example, the following example creates a Collation object with Primary level of comparison and locale fr.

Collation.builder().collationStrength(CollationStrength.PRIMARY).locale("fr").build()));

You can specify collation at the collection level, at an index level, or at a collation-supported operation level:

Collection Level

To specify collation at the collection level, pass a Collation object as an option to the createCollection() method. To specify options to the createCollection method, use the CreateCollectionOptions class.

database.createCollection("myColl", new CreateCollectionOptions().collation(
                              Collation.builder()
                                    .collationStrength(CollationStrength.PRIMARY)
                                    .locale("fr").build()));

Index Level

To specify collation for an index, pass a Collation object as an option to the createIndex() method. To specify index options, use the IndexOptions class.

IndexOptions collationIndexOptions = new IndexOptions().name("collation-fr")
                                       .collation(Collation.builder()
                                       .collationStrength(CollationStrength.SECONDARY)
                                       .locale("fr").build());

collection.createIndex(
        Indexes.ascending("name"), collationIndexOptions);

Operation Level

The following operations support collation by specifying the Collation object to their respective Iterable object.

• MongoCollection.aggregate()

• MongoCollection.distinct()

• MongoCollection.find()

• MongoCollection.mapReduce()

For example:

Collation collation = Collation.builder()
                                 .collationStrength(CollationStrength.SECONDARY)
                                 .locale("fr").build();

collection.find(Filters.eq("category", "cafe")).collation(collation);

collection.aggregate(Arrays.asList(
                         Aggregates.group("$category", Accumulators.sum("count", 1))))
          .collation(collation);

The following operations support collation by specifying the Collation object as an option using the corresponding option class for the method:

• MongoCollection.count()
• MongoCollection.deleteOne()
• MongoCollection.deleteMany()
• MongoCollection.findOneAndDelete()
• MongoCollection.findOneAndReplace()
• MongoCollection.findOneAndUpdate()
• MongoCollection.updateOne()
• MongoCollection.updateMany()

• MongoCollection.bulkWrite() for:

  • DeleteManyModel and DeleteOneModel using DeleteOptions to specify the collation
  • ReplaceOneModel, UpdateManyModel, and UpdateOneModel using UpdateOptions to specify the collation.

For example:

Collation collation = Collation.builder()
                                 .collationStrength(CollationStrength.SECONDARY)
                                 .locale("fr").build();

collection.count(Filters.eq("category", "cafe"), new CountOptions().collation(collation));

collection.updateOne(Filters.eq("category", "cafe"), set("stars", 1), 
                     new UpdateOptions().collation(collation));

collection.bulkWrite(Arrays.asList(
                new UpdateOneModel<>(new Document("category", "cafe"),
                                     new Document("$set", new Document("x", 0)), 
                                     new UpdateOptions().collation(collation)),
                new DeleteOneModel<>(new Document("category", "cafe"), 
                                     new DeleteOptions().collation(collation))));

For more information on collation, including the supported locales, refer to the manual.

Other MongoDB 3.4 features

• Support for specification of maximum staleness for secondary reads
• Support for the MongoDB handshake protocol.
• Builders for eight new aggregation pipeline stages
• Helpers for creating read-only views
• Support for the linearizable read concern

Support for JNDI

The synchronous driver now includes a JNDI ObjectFactory implementation.

Upgrading

See the upgrading guide on how to upgrade to 3.4.