Toothpick question

ToothpickQuestion.kt

package bfreuden

import toothpick.InjectConstructor
import toothpick.ProvidesSingleton
import toothpick.ktp.KTP
import toothpick.ktp.binding.bind
import toothpick.ktp.binding.module
import javax.inject.Named
import javax.inject.Provider
import javax.inject.Scope
import javax.inject.Singleton

/*

    The app has many shard (2 in this example) having the same object structure.
    All objects inside shards are singletons:
     - unique database client for all DAOs
     - unique FooDAO (injected into the PowerDAO)
    ! denotes singletons of the shard1 scope.
    ? denotes singletons of the shard2 scope.

                                 app (scope)
                                   /   \
                        -----------     ------------
                       /                            \
                shard1 (scope)                       shard2 (scope)
                  /      \                             /      \
           !PowerDAO   !FooDAO                   ?PowerDAO   ?FooDAO
            /     \          \                    /     \          \
       !FooDAO    !DBCLient   !DBCLient       ?FooDAO  ?DBCLient   ?DBCLient
          |                                      |
      !DBCLient                              ?DBCLient
 */

@Scope
@Retention(AnnotationRetention.RUNTIME)
annotation class ShardSingleton

@ProvidesSingleton
@InjectConstructor
@ShardSingleton
class DBClientProvider(@Named("appConfig")val appConfig: Map<String, String>): Provider<DBClient> {
    override fun get() = DBClient(appConfig["dpPort"]!!.toInt())
}

class DBClient(val port: Int)

@Singleton // the FooDAO is not a singleton without this annotation
@ShardSingleton
@InjectConstructor
class FooDAO(val dbClient: DBClient)

@Singleton
@ShardSingleton
@InjectConstructor
class PowerDAO(val dbClient: DBClient, val fooDAO: FooDAO)

@Singleton
@ShardSingleton
@InjectConstructor
class Shard(@Named("appConfig")val appConfig: Map<String, String>, val fooDAO: FooDAO, val powerDAO: PowerDAO)

@InjectConstructor
class App(@Named("appConfig")val appConfig: Map<String, String>) {

    var shard1: Shard = KTP.openScopes("app", "shard1")
        .supportScopeAnnotation(ShardSingleton::class.java)
        .installModules(module {
            // does not work without this explicit binding
            bind<DBClient>().toProvider(DBClientProvider::class)
    }).getInstance(Shard::class.java)

    var shard2: Shard = KTP.openScopes("app", "shard2")
        .supportScopeAnnotation(ShardSingleton::class.java)
        .installModules(module {
            // does not work without this explicit binding
            bind<DBClient>().toProvider(DBClientProvider::class)
    }).getInstance(Shard::class.java)

}

fun main() {
    val app = KTP.openScope("app")
        .installModules(
            module {
                bind<Map<String, String>>().withName("appConfig").toInstance(mapOf("dpPort" to "12"))
            }
        )
        .getInstance(App::class.java)

    val shard1 = app.shard1
    println("shard1 $shard1")
    println("shard1.appConfig ${shard1.appConfig}")
    println("shard1.fooDAO ${shard1.fooDAO} (${shard1.fooDAO.dbClient})")
    println("shard1.powerDAO ${shard1.powerDAO} (${shard1.powerDAO.fooDAO})")
    println("shard1.powerDAO.dbClient ${shard1.powerDAO.dbClient}")
    println("shard1.powerDAO.fooDAO ${shard1.powerDAO.fooDAO} (${shard1.powerDAO.fooDAO.dbClient})")

    println()

    val shard2 = app.shard2
    println("shard2 $shard2")
    println("shard2.appConfig ${shard2.appConfig}")
    println("shard2.fooDAO ${shard2.fooDAO} (${shard2.fooDAO.dbClient})")
    println("shard2.powerDAO ${shard2.powerDAO} (${shard2.powerDAO.fooDAO})")
    println("shard2.powerDAO.dbClient ${shard2.powerDAO.dbClient}")
    println("shard2.powerDAO.fooDAO ${shard2.powerDAO.fooDAO} (${shard2.powerDAO.fooDAO.dbClient})")
}
/*

-------------------
Program output:
=> FooDAO and DBClient are shard singletons

shard1 bfreuden.Shard@6b57696f
shard1.appConfig {dpPort=12}
shard1.fooDAO bfreuden.FooDAO@38bc8ab5 (bfreuden.DBClient@687080dc)
shard1.powerDAO bfreuden.PowerDAO@23d2a7e8 (bfreuden.FooDAO@7a9273a8)
shard1.powerDAO.dbClient bfreuden.DBClient@687080dc
shard1.powerDAO.fooDAO bfreuden.FooDAO@7a9273a8 (bfreuden.DBClient@687080dc)

shard2 bfreuden.Shard@26a7b76d
shard2.appConfig {dpPort=12}
shard2.fooDAO bfreuden.FooDAO@4abdb505 (bfreuden.DBClient@7ce6a65d)
shard2.powerDAO bfreuden.PowerDAO@1500955a (bfreuden.FooDAO@e874448)
shard2.powerDAO.dbClient bfreuden.DBClient@7ce6a65d
shard2.powerDAO.fooDAO bfreuden.FooDAO@e874448 (bfreuden.DBClient@7ce6a65d)

-------------------
Program output without @Singleton annotation on FooDAO:
=> DBClient is a shard singleton
=> FooDAO is not a shard singleton (PowerDAO has its own instance)

shard1 bfreuden.Shard@6b57696f
shard1.appConfig {dpPort=12}
shard1.fooDAO bfreuden.FooDAO@38bc8ab5 (bfreuden.DBClient@687080dc)
shard1.powerDAO bfreuden.PowerDAO@23d2a7e8 (bfreuden.FooDAO@7a9273a8)
shard1.powerDAO.dbClient bfreuden.DBClient@687080dc
shard1.powerDAO.fooDAO bfreuden.FooDAO@7a9273a8 (bfreuden.DBClient@687080dc)

shard2 bfreuden.Shard@26a7b76d
shard2.appConfig {dpPort=12}
shard2.fooDAO bfreuden.FooDAO@4abdb505 (bfreuden.DBClient@7ce6a65d)
shard2.powerDAO bfreuden.PowerDAO@1500955a (bfreuden.FooDAO@e874448)
shard2.powerDAO.dbClient bfreuden.DBClient@7ce6a65d
shard2.powerDAO.fooDAO bfreuden.FooDAO@e874448 (bfreuden.DBClient@7ce6a65d)

-------------------
Program output without bind<DBClient>().toProvider(DBClientProvider::class):

Exception in thread "main" toothpick.locators.NoFactoryFoundException: 
No factory could be found for class bfreuden.DBClient. 
Check that the class has either a @Inject annotated constructor or contains @Inject annotated members.


*/