Nested entities that contain a reference to an aggregate root get a link to that attached to their representation. Previously, the creation of those links assumed that the reference is a materialized instance of the remote aggregate. That's now altered to be able to deal with associations, use identifiers directly or materialize to an intermediate aggregate instance to potentially use a custom lookup.
We're now registering an HttpMessageConverter to render requests for HAL FORMS using the HalFormsConfiguration present in the application.
We're currently not adding any affordances yet. The change solely enables user code to add affordances explicitly, e.g. via RepresentationModelProcessor implementations.
Fixes: #1991.
The fix for DATAREST-1535 has changed the default allowed methods for CORS requests to a smaller set than we originally returned. This commit reinstantiates the default to be set to all HTTP methods, Spring Data repositories support by default.
Related tickets: DATAREST-1535.
Finally remove the dependency to Spring WebMVC from Spring Data REST's core module. Removed previously deprecated methods and update test configuration applying customizations.
Related tickets: DATAREST-1543.
Slightly tweaked the configuration model to rather handle the CorsRegistry via RepositoryRestConfigurer.configureRepositoryRestConfiguration(…) rather than RepositoryRestConfiguration itself. That allows moving of Spring WebMVC as a dependency in the core module.
The original methods exposing access to the CorsRegistry are now still available in deprecated form to not break existing clients.
Follow-up ticket: DATAREST-1542.
Moved off Spring Framework deprecations for HttpMessageNotReadableException. This required some rearrangements of method signatures for types (hopefully) exclusively used by internal abstractions (some public, but not very friendly for user extension in the first place).
Switched to consistent use of Pageable.unpaged() instead of null. Switched to the use of new factory methods in Spring HATEOAS. Some Java 8 based improvements in request handling to simplify the implementation code. Deprecation of code that got obsolete due to the use of the factory methods.
Moved off some deprecations in Jackson APIs.
Removed a couple of unused imports. General avoidance of common warnings. Suppression where needed. Removed dead code in configuration.
