Mayowa Adegeye mayojava

Android Engineer. Backend API Engineer. Lover of algorithms, architecture and clean code

mayojava / user_orders.kt

Last active October 9, 2018 18:47

Shows a function that calls two asynchronous functions to login in a user and fetch list of orders

	fun showUserOrders(username: String, password: String) {
	val user = login(username, password)
	val orders = fetchUserOrders(user.userId)
	showUserOrders(orders)
	}

	fun login(username: String, password: String) { }

	fun fetchUserOrders(userId: Long) { }

mayojava / user_orders_callback.kt

Created October 9, 2018 18:27

callback implementation to fetch user orders

	fun showUserOrders(username: String, password: String) {
	login(username, password) {
	user -> fetchUserOrders(user.userId) {
	orders -> showUserOrders(orders)
	}
	}
	}

	fun login(username: String, password: String, callback: (User) -> Unit)

mayojava / user_orders_rxjava.kt

Created October 9, 2018 18:45

RxJava implementation of show user orders

	fun showUserOrders(username: String, password: String) {
	login(username, password)
	.flatMap { user -> fetchUserOrders(user.userId) }
	.subscribeOn(Schedulers.io())
	.observeOn(AndroidSchedulers.mainThread())
	.subscribe { showOrders(it) }
	}

	fun login(username: String, password: String): Single<User>

mayojava / user_orders_coroutines.kt

Created October 10, 2018 18:57

coroutine implementation of fetch user orders snippet

	fun showUserOrders(username: String, password: String) = GlobalScope.launch(Dispatchers.Main) {
	val user = withContext(Dispatchers.Default) { login(username, password) }
	val orders = withContext(Dispatchers.Default) { fetchUserOrders(user.userId) }
	showUserOrders(orders)
	}

	suspend fun login(username: String, password: String) { }

	suspend fun fetchUserOrders(userId: Long) { }

mayojava / coroutines.kt

Created October 17, 2018 18:53

	fun main(args: Array<String>) = runBlocking {
	repeat(100000) {
	launch {
	delay(100)
	println("coroutine $it")
	}
	}
	}

mayojava / withcontext.kt

Created October 17, 2018 18:56

	public fun withContext(
	context: CoroutineContext,
	block: suspend CorotuineScope.() -> T
	): T

mayojava / withcontext_sample.kt

Created October 17, 2018 18:57

	fun main (args: Array<String>) = runBlocking {
	println("current thread: ${Thread.currentThread().name}")

	//switch to default Dispatcher
	val result = withContext(Dispatchers.Default) {
	delay(500)
	println("Thread: ${Thread.currentThread().name}")
	100
	}

mayojava / async_syntax.kt

Created October 17, 2018 18:58

	fun CoroutineScope.async(
	context: CoroutineContext = EmptyCorotuineContext,
	start: CoroutineStart = CoroutineStart.DEFAULT,
	block: suspend CoroutineScope.() -> Unit
	): Deferred<T>

mayojava / launch_sample.kt

Created October 17, 2018 19:00

	fun main(args: Array<String>) = runBlocking {
	launch {
	delay(1_000)
	println("from launch coroutine body")
	}
	println("from runblocking")
	}
	//print
	from runblocking
	from launch coroutine body

mayojava / async_parallel_sample.kt

Created October 17, 2018 19:01

	fun main(args: Array<String>) = runBlocking {
	val time = measureTimeMillis {
	val first = async { firstNumber() }
	val second = async { secondNumber() }
	val third = async { thirdNumber() }

	val result = first.await() + second.await() + third.await()
	}

	println(time) //prints 7 seconds