Property Deleagtion

DefaultPropertyDelegation.kt

class Database(private context: Context) {
        val helper: SQLiteOpenHelper by lazy { SQLiteOpenHelper(context,...-) }
        val observableProperty: Int by Delegates.observable { thisRef , newValue , oldValue -> doSomething()}
        val vetoableProperty: Int by Delegates.vetoable { _ , newValue , oldValue -> return if (oldValue < newValue) true else false  }
}

ReferenceDelegate.kt

class WeakReferenceProperty<Param>(referencedParam: Param?) : ReadOnlyProperty<Any, Param?> {

    val weakReference: WeakReference<Param?> by lazy { WeakReference(referencedParam) }

    override fun getValue(thisRef: Any, property: KProperty<*>): Param? {
        return weakReference.get()
    }
}

class SoftReferenceProperty<Param>(referencedParam: Param?) : ReadOnlyProperty<Any, Param?> {

    val softReference: SoftReference<Param?> by lazy { SoftReference(referencedParam) }

    override fun getValue(thisRef: Any, property: KProperty<*>): Param? {
        return weakReference.get()
    }
}

//funciones para obtener las propiedades delegadas
 fun <Param> weak(param: Param) = WeakReferenceProperty(param)
 fun <Param> soft(param: Param) = SoftReferenceProperty(param)

//uso
class ItemAdapter(private context: Context): RecyclerView.Adapter() {
 val weakContext: Context? by weak(context)
 val softContext: Context? by soft(context)
}