Spring Data 2023.0 (Ullman) Release Notes

General Themes

AOT reflection Hints for Querydsl Q classes
Add support for Kotlin Inline classes
Add keyset-based scrolling for MongoDB and JPA modules

Participating Modules

Details

Spring Data Build - 3.1
Spring Data Commons - 3.1
Spring Data JPA - 3.1
Spring Data Relational - 3.1
Spring Data MongoDB - 4.1
Spring Data Neo4j - 7.1
Spring Data Elasticsearch - 5.1
Spring Data Couchbase - 5.1
Spring Data for Apache Cassandra - 4.1
[geode]
Spring Data Redis - 3.1
Spring Data REST - 4.1
Spring Data KeyValue - 3.1
Spring Data LDAP - 3.1

New and Noteworthy

Spring Data Commons - 3.1

Scroll API

Scrolling is a more fine-grained approach to iterate through larger results set chunks. Scrolling consists of a stable sort, a scroll type (Offset- or Keyset-based scrolling) and result limiting. You can define simple sorting expressions using property names and define static result limiting using the Top or First keyword through query derivation. You can concatenate expressions to collect multiple criteria into one expression.

Window<User> users = repository.findFirst10ByLastnameOrderByFirstname("Doe", OffsetScrollPosition.initial());
do {

  for (User u : users) {
    // consume the user
  }

  // obtain the next Scroll
  users = repository.findFirst10ByLastnameOrderByFirstname("Doe", users.positionAt(users.size() - 1));
} while (!users.isEmpty() && users.hasNext());

An easier variant uses WindowIterator:

WindowIterator<User> users = WindowIterator.of(position -> repository.findFirst10ByLastnameOrderByFirstname("Doe", position))
  .startingAt(OffsetScrollPosition.initial());

while (users.hasNext()) {
  User u = users.next();
  // consume the user
}

Scrolling can be used through query methods, Querydsl, and Query by Example executors through the Fluent Query API:

interface PersonRepository extends Repository<Person, Long>, QueryByExampleExecutor<Person> {	
}

repository.findBy(Example.of(…), q -> q.sortBy(…).scroll(OffsetScrollPosition.initial()));

Scrolling supports two flavors:

Offset-based scrolling applying limit/offset in queries.
Keyset-based scrolling leveraging index support and sorting to retrieve sorted query sub-results

Spring Data JPA - 3.1

Spring Data JPA introduces HQL and JPQL parser!

One of Spring Data JPA’s handy features is letting users plugin in custom JPA queries through its @Query annotation. This isn’t too rigid because developers can still apply Sort parameters, giving end-users the ability to plugin various sort criteria. Moreover, Spring Data JPA supports paging, which requires the ability to count result sets.

interface SampleRepository extends CrudRepository<Employee, Long> {

    @Query("select e from Employee e where e.firstName = ?1")
    List<Employee> findCustomEmployees(String firstName, Sort sort);
}

Thus, we have allowed supported users by taking their @Query-provided queries and applied additional order by clauses and count() operations to support these modes of operations. Unfortunately, that support has been tricky the more complex custom queries become since for a long time, we only had a regular expression utility to support that.

The query above with a Sort.by("lastName") would turn into:

  select e
    from Employee e
   where e.firstName = ?1
order by e.lastName

With spring-data-jpa#2814, we have introduced a parser both for HQL (Hibernate Query Language) and spec-defined JPQL (JPA Query Language). Now, anytime you write a query, it is run through a proper parser, and it becomes much easier to curate the "final" query users need, whether that involves adding additional sort criteria to a query that already has an order by clause, or adding a new one should none exist.

We can also proper put the count() found in the right place to support Pageable queries that have a custom query.

What’s especially nice is that you don’t have to do anything. Spring Data JPA can detect whether Hibernate is on the classpath and switch between HQL or plain old JPQL.

Support for Keyset-based scrolling

As outlined in Spring Data Commons, Spring Data JPA provides support for the newly introduced Scroll API for derived query methods, Querydsl, and Query-by-Example usage. Stored procedures and String-based queries cannot be used for keyset-scrolling.

Spring Data Relational - 3.1

Spring Data MongoDB - 4.1

Explicit Client-Side Field Level Encryption (CSFLE)

Explicit CSFLE uses the MongoDB driver’s optional encryption library (org.mongodb:mongodb-crypt) to perform encryption and decryption tasks during the mapping process of queries, updates and aggregations ($match stage). Other than automatic encryption, there is no need to provide a Schema with encryption information upfront.

The newly introduced @ExplicitEncrypted annotation makes sure to cypher values of annotated properties with a chosen encryption algorithm and Data Encryption Key (DEK) before sending them to the MongoDB server.

@EncryptedField(
  algorithm = "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic",
  altKeyName = "secret-key"
)
String ssn;

Improved `ReadPreference` & `ReadConcern` handling

The new API now allows defining both, the ReadPreference, how the client routes an operation to members of a replica set and the ReadConcern, that controls read consistency and isolation level, for queries, aggregations and geo-near operations.

Support for `let` and `pipeline` in `$lookup` aggregation stage

The newly introduced options allow making use of MongoDB’s ability to perform correlated-subqueries which also removes the need for an equality match on the foreign fields.

Aggregation.lookup().from("restaurants")
  .localField("restaurant_name")
  .foreignField("name")
  .let(newVariable("orders_drink").forField("drink"))
  .pipeline(match(ctx -> new Document("$expr", new Document("$in", List.of("$$orders_drink", "$beverages")))))
  .as("matches");

Support for Keyset-based scrolling

As outlined in Spring Data Commons, Spring Data MongoDB provides support for the newly introduced Scroll API.

Spring Data Neo4j - 7.1

Spring Data Elasticsearch - 5.1

Spring Data Couchbase - 5.1

Spring Data for Apache Cassandra - 4.1

Spring Data Redis - 3.1

Spring Data KeyValue - 3.1

Spring Data REST - 4.1

Support for returning response bodies when deleting item resources — #2225

RepositoryRestConfiguration now exposes a ….setReturnResponseBodyOnDelete(…) to forcibly enable or disable a response body written when deleting item resources. The default (the option set to null) now considers the Accept header, similar to what we already do for POST and PUT requests. If present, a body will be returned alongside a status code of 200. If not, it will stay a 204.

Support for `Slice` as return type for methods backing query method resources — #2235

Repository methods returning a Slice are now properly turned into a Spring HATEOAS SlicedModel to then render the corresponding SliceMetadata and hypermedia elements to traverse the previous and next slice.

Support to receive aggregate references as request parameters — #2239

To translate URIs submitted as request parameters into Spring Data aggregate references, we now provide a (Association)AggregateReference type to be used as a handler method parameter. It allows the resolution of aggregate identifiers, the aggregate itself or a jMolecules Association.