idiomatic-kotlin-course/notebooks/Multitasking.ipynb

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 "cells": [
  {
   "cell_type": "code",
   "source": [
    "%use coroutines"
   ],
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   "outputs": [],
   "execution_count": null
  },
  {
   "metadata": {},
   "cell_type": "markdown",
   "source": "# Три оси многозадачности"
  },
  {
   "cell_type": "markdown",
   "source": "### Синхронный х однопоточный х неконкурентный ",
   "attachments": {},
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "repeat(10){\n",
    "    println(\"Line number $it\")\n",
    "}"
   ],
   "metadata": {
    "datalore": {
     "node_id": "XzjwoelmODMg8pmaJRe1KK",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [
    "import java.util.stream.*\n",
    "\n",
    "IntStream.range(0, 100).sum()"
   ],
   "metadata": {
    "datalore": {
     "node_id": "UuTmCNAMCpUAHaAwWVYJPy",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Синхронный х однопоточный х конкурентный",
   "attachments": {},
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     "node_id": "f6DGHwBOIRvKuYjtxVRn0W",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "val list = (0..100).toMutableList()\n",
    "\n",
    "list.forEach{\n",
    "    if(it % 2 == 0) list.remove(it)\n",
    "}"
   ],
   "metadata": {
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     "node_id": "O1DPfMSAedOChaqU5JWXrU",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [],
   "metadata": {
    "datalore": {
     "node_id": "N3QIwvANEngnvMgsCVJatN",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Синхронный х многопоточный х неконкурентный",
   "attachments": {},
   "metadata": {
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   }
  },
  {
   "cell_type": "code",
   "source": [
    "val sum = IntStream.range(0, 100).parallel().sum()\n",
    "\n",
    "println(sum)"
   ],
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   "outputs": [],
   "execution_count": null
  },
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   "cell_type": "code",
   "source": [],
   "metadata": {
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     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Асинхронный х однопоточный х неконкурентный",
   "attachments": {},
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "fun runLongTask(result: Int = 8): Int {\n",
    "  Thread.sleep(100)\n",
    "  println(\"Task complete: $result\")\n",
    "  return result\n",
    "}"
   ],
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     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [
    "import java.util.concurrent.*\n",
    "\n",
    "val executor = Executors.newSingleThreadExecutor()\n",
    "\n",
    "val future = executor.submit<Int> {\n",
    "    val result = runLongTask()\n",
    "    println(result)\n",
    "    result\n",
    "}\n",
    "\n",
    "future.get()"
   ],
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     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Асинхронный х однопоточный х конкурентный ",
   "attachments": {},
   "metadata": {
    "datalore": {
     "node_id": "nyjKPayaltq8gBzq2bIP1c",
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     "hide_output_from_viewers": true
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   }
  },
  {
   "cell_type": "code",
   "source": [
    "interface Observable{\n",
    "    fun onChange(callback: (Int) -> Unit)\n",
    "}\n",
    "\n",
    "val observable: Observable by lazy{ TODO() }"
   ],
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   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [
    "val list: MutableList<Int> = mutableListOf<Int>()\n",
    "\n",
    "observable.onChange { \n",
    "    list.add(it)\n",
    "}"
   ],
   "metadata": {
    "datalore": {
     "node_id": "1in8iE7mL9m895XWUNh0Sl",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Асинхронный х многопоточный х неконкурентный",
   "attachments": {},
   "metadata": {
    "datalore": {
     "node_id": "TczpOZrkCKogcT7x7XWAUT",
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     "hide_output_from_viewers": true
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   "cell_type": "code",
   "source": [],
   "metadata": {
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     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [
    "val executor: ExecutorService = Executors.newFixedThreadPool(4)\n",
    "\n",
    "repeat(8){\n",
    "    executor.submit{\n",
    "        runLongTask(it)\n",
    "    }\n",
    "}"
   ],
   "metadata": {
    "datalore": {
     "node_id": "9NS1h5b5lJ0BEzieUt6xrr",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Синхронный х многопоточный х конкурентный",
   "attachments": {},
   "metadata": {
    "datalore": {
     "node_id": "REBgToVc8iKIrODCWXPdZj",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "import kotlin.io.path.Path\n",
    "import kotlin.io.path.writeText\n",
    "\n",
    "val file = Path(\"someFile.txt\")\n",
    "\n",
    "val data: List<String> = emptyList()\n",
    "\n",
    "data.stream()\n",
    "    .parallel()\n",
    "    .forEach {  \n",
    "        file.writeText(it)\n",
    "    }"
   ],
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     "hide_output_from_viewers": true
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   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": "### Асинхронный х многопоточный х конкурентный",
   "attachments": {},
   "metadata": {
    "datalore": {
     "node_id": "XDCp5EjIq8v6ABeo5q2K6S",
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     "hide_output_from_viewers": true
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  },
  {
   "cell_type": "code",
   "source": [
    "val cache = mutableMapOf<Int, Int>\n",
    "\n",
    "val consumer: (Int) -> Unit = TODO()\n",
    "\n",
    "\n",
    "repeat(8){ i->\n",
    "    executor.submit{\n",
    "        val result = cache.getOrPut(i){\n",
    "            runLongTask(i)\n",
    "        }\n",
    "        consumer(result)\n",
    "    }\n",
    "}"
   ],
   "metadata": {
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   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "## Инструменты"
   ],
   "attachments": {},
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     "type": "MD",
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   }
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### Thread"
   ],
   "attachments": {},
   "metadata": {
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     "node_id": "qjWpglMy3eSM475ozgnDPA",
     "type": "MD",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "import kotlin.concurrent.*\n",
    "\n",
    "val t = thread {\n",
    "    runLongTask()\n",
    "}\n",
    "t.join()"
   ],
   "metadata": {
    "datalore": {
     "node_id": "nEZ6jKJhVHhsjMvptTQ3rU",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "code",
   "source": [],
   "metadata": {
    "datalore": {
     "node_id": "k35GcE4VUIMtrznZ0C3BmC",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### Future"
   ],
   "attachments": {},
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     "node_id": "bX0GaqyAH6q7Max0Tky7DW",
     "type": "MD",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "val future = executor.submit<Int>{\n",
    "    runLongTask()\n",
    "}\n",
    "\n",
    "future.get()\n",
    "future.cancel(true)"
   ],
   "metadata": {
    "datalore": {
     "node_id": "TVhCm0JtWiYFFqWYORxuya",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### CompletableFuture"
   ],
   "attachments": {},
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     "node_id": "a5BY9U8m9OeZSSsS0yGRSZ",
     "type": "MD",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "import java.util.concurrent.*\n",
    "\n",
    "val cf = CompletableFuture.supplyAsync{\n",
    "    runLongTask()\n",
    "}\n",
    "\n",
    "val cf2 = cf.whenComplete{ res, _ ->\n",
    "    runLongTask(res - 1)\n",
    "}\n",
    "\n",
    "val cf3 = cf.whenComplete{ res, _ ->\n",
    "    runLongTask(res + 1)\n",
    "}\n",
    "\n",
    "cf2.join()\n",
    "cf3.join()"
   ],
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     "node_id": "2rchFZt5trGqzOCuU3aPvz",
     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### Lock"
   ],
   "attachments": {},
   "metadata": {
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     "node_id": "izHWuE5ZZo1hphjMmc7BHj",
     "type": "MD",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "import java.util.concurrent.locks.*\n",
    "\n",
    "val list = mutableListOf<Int>()\n",
    "val lock = ReentrantLock()\n",
    "\n",
    "val cf4 = CompletableFuture.supplyAsync{\n",
    "    val res = runLongTask(4)\n",
    "    lock.withLock { \n",
    "        list.add(res)\n",
    "    }\n",
    "}\n",
    "\n",
    "val cf5 = CompletableFuture.supplyAsync{\n",
    "    val res = runLongTask(5)\n",
    "    lock.withLock { \n",
    "        list.add(res)\n",
    "    }\n",
    "}\n",
    "\n",
    "cf4.join()\n",
    "cf5.join()\n",
    "\n",
    "list"
   ],
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     "type": "CODE",
     "hide_input_from_viewers": true,
     "hide_output_from_viewers": true
    }
   },
   "outputs": [],
   "execution_count": null
  },
  {
   "metadata": {},
   "cell_type": "markdown",
   "source": "Reactive streams"
  },
  {
   "metadata": {},
   "cell_type": "code",
   "source": [
    "class A(val value: Int)\n",
    "class B(val value: Int)\n",
    "\n",
    "val aFlow = flowOf<A>()\n",
    "val bFlow = flowOf<B>()\n",
    "\n",
    "val combined = aFlow.zip(bFlow){ a, b->\n",
    "    a.value + b.value\n",
    "}.debounce(2.seconds)"
   ],
   "outputs": [],
   "execution_count": null
  },
  {
   "metadata": {},
   "cell_type": "markdown",
   "source": "Actor"
  },
  {
   "metadata": {},
   "cell_type": "code",
   "source": [
    "sealed class Event {\n",
    "    class Open(val transactionId: Int): Event()\n",
    "    class Close(val tranactionId: Int): Event()\n",
    "}\n",
    "\n",
    "fun interface Actor {\n",
    "    suspend fun receive(event: Event)\n",
    "}\n",
    "\n",
    "val actor = object : Actor {\n",
    "    private var transaction: Int? = null\n",
    "    override suspend fun receive(event: Event) {\n",
    "        when (event) {\n",
    "            is Event.Open -> if (transaction != null) {\n",
    "                error(\"Transaction already open\")\n",
    "            } else {\n",
    "                transaction = event.transactionId\n",
    "            }\n",
    "            is Event.Close ->if (transaction != event.tranactionId) {\n",
    "                error(\"Wrong transaction id: ${event.tranactionId}\")\n",
    "            } else {\n",
    "                transaction = null\n",
    "            }\n",
    "        }\n",
    "    }\n",
    "\n",
    "}"
   ],
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "## Сорта асинхронности"
   ],
   "attachments": {},
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     "hide_output_from_viewers": true
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   }
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### Callback"
   ],
   "attachments": {},
   "metadata": {
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     "node_id": "kb1ccsTMIZX3aacLF6gPrJ",
     "type": "MD",
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     "hide_output_from_viewers": true
    }
   }
  },
  {
   "cell_type": "code",
   "source": [
    "import java.net.*\n",
    "import java.net.http.*\n",
    "import java.net.http.HttpResponse.*\n",
    "\n",
    "val client: HttpClient = HttpClient.newHttpClient()\n",
    "\n",
    "val request :  HttpRequest = HttpRequest.newBuilder()\n",
    "    .uri(URI.create(\"https://sciprog.center\"))\n",
    "    .GET().build()\n",
    "\n",
    "val regex = \"\"\"href=\\\"(.+\\.png)\\\"\"\"\".toRegex()\n",
    "\n",
    "client.sendAsync(request, BodyHandlers.ofString())\n",
    "    .thenApply{ it.body() }\n",
    "    .thenApply{ \n",
    "        val resources = regex.findAll(it).map{it.groupValues[1]}\n",
    "\n",
    "        resources.forEach { resourceName->\n",
    "            val resourceRequest :  HttpRequest = HttpRequest.newBuilder()\n",
    "                .uri(URI.create(\"https://sciprog.center$resourceName\"))\n",
    "                .GET().build()\n",
    "            client.sendAsync(resourceRequest, BodyHandlers.ofByteArray()).thenAccept{ resourceResponse ->\n",
    "                val bodyBytes = resourceResponse.body()\n",
    "                //do something with the body\n",
    "            }\n",
    "        }\n",
    "        resources\n",
    "    }\n",
    "    .thenAccept{ println(it.toList()) }\n",
    "    .join()"
   ],
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   },
   "outputs": [],
   "execution_count": null
  },
  {
   "cell_type": "markdown",
   "source": [
    "#### Реактивные потоки"
   ],
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    }
   },
   "outputs": [],
   "execution_count": null
  }
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