shkschneider

object Coroutines {
   fun io(work: suspend (() -> Unit)): Job =
      CoroutineScope(Dispatchers.IO).launch {
          work()
      }
   fun <T: Any> ioThenMain(work: suspend (() -> T?), callback: ((T?) -> Unit)): Job =
      CoroutineScope(Dispatchers.Main).launch {
          val data = CoroutineScope(Dispatchers.IO).async rt@ {
              return@rt work()
          }.await()

shkschneider

object DataManager {

    @WorkerThread
    fun dummy(context: Context) {
        with(MyDatabase.get(context)) {
            users().insert(User(login = "user.name"))
            projects().insert(Project(name = "project.name"))
            notifications().insert(Notification(msg = "created"))
        }
    }

shkschneider

@UiThread
fun getUsers(context: Context): LiveData<List<User>> {
    if (!::users.isInitialized) {
        users = MutableLiveData()
        Coroutines.ioThenMain({
            DataManager.getUsers(context)
        }) {
            users.value = it
        }
    }

shkschneider

inline fun <reified T: Any> Activity.extra(key: String, default: T? = null) = lazy {
    val value = intent?.extras?.get(key)
    if (value is T) value else default
}
inline fun <reified T: Any> Activity.extraNotNull(key: String, default: T? = null) = lazy {
    val value = intent?.extras?.get(key)
    requireNotNull(if (value is T) value else default) { key }
}

shkschneider

inline fun <reified T: Any> Fragment.extra(key: String, default: T? = null) = lazy {
    val value = arguments?.get(key)
    if (value is T) value else default
}
inline fun <reified T: Any> Fragment.extraNotNull(key: String, default: T? = null) = lazy {
    val value = arguments?.get(key)
    requireNotNull(if (value is T) value else default) { key }
}

shkschneider

const val ID = "id"

class MyActivity : Activity() {

    private val id1 by extra<String>(ID) // String?
    private val id2 by extraNotNull<String>(ID) // String

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        requireNotNull(id1, id2)

shkschneider

fun requireNotNulls(vararg any: Any?) {
    any.forEach {
        requireNotNull(value = it)
    }
}
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    requireNotNulls(id1, id2)
}

shkschneider

class Repository {

    init{
    }

    companion object {
        private val CACHE = TimeUnit.HOURS.toSeconds(4)
    }
    
}

shkschneider

fun alwaysReturnsNull(position: Int): String? {
    if ((position % 10) == 0) {
        when (position) {
            10 -> "one"
            20, 30 -> "two"
            else -> "three"
        }
    }
    return null
}

shkschneider

fun returnsUnit() {
    methodReturningBoolean()
}
    
fun returnsAnImplicitBoolean() = methodReturningBoolean()

private fun methodReturningBoolean() = true