Spring-Boot: Dependency Injection depending on the configuration (and using interfaces)

Question

I have the following question regarding the structure of my application architecture. Assume my application consists of the following components

First of all a @ConfigurationProperties , which initializes my needed properties (here only a type to select a provider). In addition, a bean of the type " Provider " is to be registered at this point depending on the specified type. This type is implemented as an interface and has two concrete implementations in this example ( ProviderImplA & ProviderImplB ).

@Configuration
@Profile("provider")
@ConfigurationProperties(prefix = "provider")
@ConditionalOnProperty(prefix = "provider", name = ["type"])
class ProviderConfiguration {
    lateinit var type: String

    @Bean(name = ["provider"])
    fun provider(): Provider {
        return when (type) {
            "providerA" -> ProviderImplA()
            "providerB" -> ProviderImplB()
        }

    }

}

Next, only the two concrete implementation of the interface.

class ProviderImplA: Provider {

    @Autowired
    lateinit var serviceA: ServiceA

}

class ProviderImplB: Provider {

    @Autowired
    lateinit var serviceA: ServiceA
    @Autowired
    lateinit var serviceB: ServiceB
    @Autowired
    lateinit var serviceC: ServiceC

}

And last but not least the interface itself.

interface Provider{
    fun doSomething()
}

Now to the actual problem or better my question:
Because my concrete implementations (ProviderImplA and ProviderImplB) are no valid defined beans (missing annotation eg @Component), but they have to use their own @Service components, it is not possible to use @Autworie at this point. I would like to avoid different profiles/configurations if possible, therefore the initialization by property. How can I still use the individual @Service's within my implementations and still create the provider beans manually, depending on the configuration (only one provider exists at runtime)? Maybe you have other suggestions or improvements?

Answer 1

When instantiating objects directly, spring cannot control its life cycle, so you must create an @Bean for each 'Provider'

@Bean(name = ["providerA"])
@Lazy
fun providerA(): Provider {
  return ProviderImplA()
}

@Bean(name = ["providerB"])
@Lazy
fun providerB(): Provider {
   return ProviderImplB()
}

IdentityProviderConfiguration class

IdentityProviderConfiguration {
  var context: ApplicationContext
  ...

  fun provider(): Provider {
    return when (type) {
     "providerA" -> context.getBean("providerA")
     "providerB" -> context.getBean("providerB")
    }
  }

}