Evaluate usage of vendor extensions to add annotations to generated code

[ChristophB]

There are supported vendor extensions to extend the generated spring-boot code with additional annotations like "org.springframework.data.neo4j.core.schema.Relationship", "org.springframework.data.neo4j.core.schema.Node", etc.

We could use these extensions to make the top-api models compatible with spring-data-neo4j. This would enable us to store the objects natively in neo4j without complex and computationally intensive mappings.

Some more examples for annotations we might need for our model classes:

• org.springframework.data.annotation.Id
• org.springframework.data.annotation.Version
• org.springframework.data.annotation.CreatedDate
• org.springframework.data.annotation.CreatedBy
• org.springframework.data.annotation.LastModifiedDate
• org.springframework.data.annotation.LastModifiedBy
• org.springframework.data.neo4j.core.schema.Node
• org.springframework.data.annotation.PersistenceConstructor
• org.springframework.data.neo4j.core.schema.GeneratedValue
• org.springframework.data.neo4j.core.schema.DynamicLabels
• org.springframework.data.neo4j.core.schema.Relationship(type = "BELONGS_TO")
• org.springframework.data.neo4j.core.schema.Relationship(type = "CURRENT_VERSION")
• ...

We can add these annotations to the schemas/top-api.yml file with x-field-extra-annotation and x-class-extra-annotation properties.

Problems

Versions are not part of the top-api. Thus, it must be evaluated how they can be incorporated.