Add support for fluent QueryResultConverter

[mp911de]

We now support configuring a QueryResultConverter that has access to the raw result Document and the mapped result object that has been materialized from MongoConverter:

List<Optional<Jedi>> result = template.query(Person.class)
                        .as(Jedi.class)
                        .matching(query(where("firstname").is("luke")))
                        .map((document, reader) -> Optional.of(reader.get()))
                        .all();

This is useful to either wrap, post-process results contextually or apply further transformations based on the result Document. Changes apply for imperative and reactive find, geoNear and aggregations.

TODO:

• QueryResultConverter.entity() (returning the converted object) is a good naming fit for queries, but with projections or aggregations we might to name it differently

[Copilot]

Copilot reviewed 21 out of 24 changed files in this pull request and generated no comments.

Files not reviewed (3)

• pom.xml: Language not supported
• spring-data-mongodb-distribution/pom.xml: Language not supported
• spring-data-mongodb/pom.xml: Language not supported

Comments suppressed due to low confidence (2)

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java:3010

• [nitpick] The unchecked cast used when comparing 'resultConverter' to QueryResultConverter.entity() could potentially lead to runtime issues. Consider refactoring this comparison to improve type safety, for example by using a more explicit identity check or redesigning the converter composition.

return resultConverter == QueryResultConverter.entity() ? (DocumentCallback<R>) readCallback : new QueryResultConverterCallback<T, R>(resultConverter, readCallback);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFindOperationSupport.java:101

• [nitpick] Resetting the result converter to QueryResultConverter.entity() in the 'as()' method may inadvertently discard any existing custom converter chain. Consider preserving or composing with the current converter to ensure intended behavior when mapping to a new return type.

return new ReactiveFindSupport<>(template, domainType, returnType, QueryResultConverter.entity(), collection, query);

[mp911de]

See also spring-projects/spring-data-cassandra#1568