RepositoryRestMvcConfiguration can no longer be subclassed

[alienisty]

Despite the class documentation states that "To customize how the exporter works, subclass this and override...", that that is no longer possible.
The restHandlerMapping() method returns a DelegatingHandlerMapping which has been made package private in commit d7f36b1 related to DATAREST-1540.
When subclassing RepositoryRestMvcConfiguration for customisation, I now get the following exception:

Caused by: java.lang.IllegalAccessError: failed to access class org.springframework.data.rest.webmvc.config.DelegatingHandlerMapping from class au.com.onyxtech.horus.config.RepositoryRestConfig$ExtendedRepositoryRestMvcConfiguration$$EnhancerBySpringCGLIB$$186fd9d8 (org.springframework.data.rest.webmvc.config.DelegatingHandlerMapping and au.com.onyxtech.horus.config.RepositoryRestConfig$ExtendedRepositoryRestMvcConfiguration$$EnhancerBySpringCGLIB$$186fd9d8 are in unnamed module of loader 'app')
	at au.com.onyxtech.horus.config.RepositoryRestConfig$ExtendedRepositoryRestMvcConfiguration$$EnhancerBySpringCGLIB$$186fd9d8.restHandlerMapping(<generated>)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
	... 89 common frames omitted

[odrotbohm]

What exactly do you need to customize? We usually recommend rather declaring a RepositoryRestMvcConfigurer for general purpose tweaks.

[alienisty]

We need to customize:

1. The auditableBeanWrapperFactory
2. The linkCollector because the default link format doesn't work for us
3. The repositoryInvokerFactory because the default one is unaware of entities managed by a polymorphic repository
4. The persistentEntityJackson2Module

I know that the documentation says that we should override any of the configure* methods, but even then, with the current implementation we are not directly able to do that, and I have a to work around it using a bridge class to make DelegatingHandlerMapping accessible, but that is a bit ugly.

I also know that RepositoryRestConfigurer allows us to customise some things, and we use it, but not all can be done through it.

[tfleis]

We need to add QuerydslPredicateArgumentResolver and our own HandlerMethodArgumentResolver. We have overwritten method RepositoryRestMvcConfiguration.defaultMethodArgumentResolvers.

[steinmaerivoet]

I'm also running into this problem wanting to override defaultMethodArgumentResolvers to add my custom HandlerMethodArgumentResolver.
My use case is I want to implement https://github.com/sipios/spring-search in Spring Data Rest so I have access to the persistentEntityResourceAssembler.

[MatthieuComtois]

We need to customize RepositoryInvokerFactory, persistentEntities, persistentEntityJackson2Module, pageableResolver. But implementing RepositoryRestConfigurer doest not allow to override it.

Any solution ?

[MatthieuComtois]

@alienisty Did you find a clean solution ? I don't get your idea using a bridge class, can you share your solution ?

[alienisty]

@MatthieuComtois, I had to resort to mokeypatching the problematic class, in my case DelegatingHandlerMapping, and I changed the access level of the class from package private to public.
Monkey patching involve copying the class source and put it in your project source under the same package, so that it will be found before in the classpath substituting the one coming from the framework's jar.
The solution is not ideal because you'll have to update the source every time you upgrade to a newer release.
I hope this helps.

[MatthieuComtois]

Thanks for the explanation, I will try it, maybe it can help us temporarily

[tgeens]

I managed to workaround this by using a BeanPostProcessor to replace the beans I wanted to override, instead of subclassing RepositoryRestMvcConfiguration