4.x MediaContext requires .build()

[romain-grecourt]

• Helidon Version: 4.0.0-ALPHA6

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The following does NOT include the default media support that is registered by io.helidon.nima.http.media.MediaContextBuilderInterceptor.

 WebServer.builder().mediaContext(MediaContext.builder());

Instead you get a MediaContext that is empty and unable to read or write any entity types.

However if you invoke .build() everything works ok.

WebServer.builder().mediaContext(MediaContext.builder().build());

The issue is that the builder implements the config type, and the config type is consumed by other parts.

// this works because the builder implements MediaContextConfig
// not because the method is overloaded to accept Supplier<MediaContextConfig>
// and the call the .get() is equivalent to .build()
WebServer.builder().mediaContext( MediaContext.builder());

[tomas-langer]

Proposed approach:

• BuildBase no longer implements prototype interface
• we generate getters for all fields, using Optional as return type for:
  • any field that is required (even primitives - as we generate boxed types for such cases, to be able to validate)
  • any field that does not have a default value and is of an object type
  • any field that returns Optional on prototype itself
• refactor all cases where this is used in builder interceptors

[tomas-langer]

Part 1 is done - we no longer accept builder where it should not have been accepted.
Part 2 - add methods that accept Supplier<? extends X> when a type is a Prototype