hello channel I am working on a Kotlin + Spring application, and wondering if this is possible or no...

# spring

[Tiago]

hello channel
I am working on a Kotlin + Spring application, and wondering if this is possible or not:

there is a properties configuration:

@ConfigurationProperties("application.custom.properties")
data class SomeProperties(
    val foo: Long,
    val bar: String,
)

application.properties:

application.custom.properties.foo=1
application.custom.properties.bar=Text Here

ok, so I have another class, just a POJO, and need to get the values from that configuration properties bean

data class ObjectBuilder(
    var fooValue: Long = SomeProperties.foo,
    var barValue: String = SomeProperties.bar,
)

is there a way of getting the SomeProperties values on a non spring context?

[ashmelev]

Something like this should work:

@Bean(name = ["objectBean"])
  fun objectBean(): ObjectBuilder =
      ObjectBuilder(
		fooValue = SomeProperties.foo,
		barValue = SomeProperties.bar
        )

[ashmelev]

Then just inject objectBean wherever you need it

[Tiago]

lets try another scenario:

@Entity
data class EntityA(
  var entityB: EntityB
)

@Entity
data class EntityB(
  var foo: Long = SomeProperties.foo
)

I want to use the SomeProperties.foo as the default value for EntityA.entityB.foo

[ashmelev]

Well, @Entity does not create a Bean (AFAIK), so you'd have to add @Component to the @Entity and then inject objectBean. Try something like:

@Entity
@Component
data class EntityB(
  @Transient private val objectBean: ObjectBuilder,
  var foo: Long = objectBean.fooValue
)

Obviously I have not tested this so I am not sure it will actually inject properly

[kqr]

I would use simple factories

[Tiago]

like how? 🤔

[Tiago]

I am using @PostConstruct to store the instance from the bean on a static context:

@PostConstruct
fun initialize() {
    instance = this
}

And then I can access this instance from a non-spring context
but I am not completely happy with this approach 😆

[kqr]

@Component
class EntityBFactory(val config: SomeProperties) {
   fun create(): EntityB = ...
}

[ashmelev]

@Tiago’s approach will work well too. I just have a personal preference against doing the necessary initialization in @PostConstruct. Not that it is wrong or would fail - it will work. Just seems untidy to my eyes 🙂

[Tiago]

yeah, I don’t like it either 😕