KPojo Dynamic Instantiate

This chapter shows how Kronos creates KPojo instances from complete KType metadata without reflective construction.

Create a KPojo from KType

Use Kronos.createKPojo(type) when generic code has a complete KType and needs a fresh KPojo instance. The runtime uses compiler-generated or explicitly registered non-reflective factories.

import com.kotlinorm.interfaces.KPojo
import com.kotlinorm.Kronos
import kotlin.reflect.typeOf

data class User(
    var id: Int? = null,
    var name: String = ""
) : KPojo

val instance = Kronos.createKPojo(typeOf<User>())
// User(id = null, name = "")

Generic helper functions can use the same API.

inline fun <reified T : KPojo> newKPojo(): T {
    return Kronos.createKPojo(typeOf<T>()) as T
}

val user = newKPojo<User>()
// User(id = null, name = "")

Result shape:

The returned value has the requested KPojo type.
Constructor parameters use the same defaults as a normal User() call.

Register Explicit Constructors

Use Kronos.registerKPojoFactory when a model type is provided from another module, a third-party package, or a factory boundary. The registration key is the exact complete KType; generic KPojo types are not supported in this release.

import com.kotlinorm.Kronos
import com.kotlinorm.utils.KPojoFactory
import kotlin.reflect.typeOf

val userRegistration = Kronos.registerKPojoFactory(typeOf<User>(), KPojoFactory { _ -> User() })
val permissionsRegistration = Kronos.registerKPojoFactory(
    typeOf<Permissions>(),
    KPojoFactory { _ -> Permissions() }
)

Each registration covers one exact type. Later registrations for the same type have higher priority; call close() to remove only that override and reveal the previous user or generated factory.

val user = Kronos.createKPojo(typeOf<User>())
userRegistration.close()
permissionsRegistration.close()

Handle Missing Factories

When no generated or registered factory matches the KType, createKPojo fails with a clear message. Enable the Kronos compiler plugin for the module that declares the KPojo, or register an explicit constructor.

data class ExternalUser(
    val id: Int
) : KPojo

Kronos.createKPojo(typeOf<ExternalUser>())

KType ... instantiation failed.
No generated or registered KPojo factory matched this class.

Register the constructor when the class cannot use generated factories.

val registration = Kronos.registerKPojoFactory(
    typeOf<ExternalUser>(),
    KPojoFactory { _ -> ExternalUser(id = 0) }
)

val external = Kronos.createKPojo(typeOf<ExternalUser>())
// ExternalUser(id = 0)

For map conversion APIs that use the same instantiation path, see 📚Map/KPojo Conversion.