From ddfd17de81d143aef83a421c57867d42ddc7ff9b Mon Sep 17 00:00:00 2001
From: Alexander Nozik <altavir@gmail.com>
Date: Fri, 5 Mar 2021 10:54:18 +0300
Subject: [PATCH] coroutine demo

---
 build.gradle.kts                       | 11 +++++---
 src/main/kotlin/demos/coroutineDemo.kt | 36 ++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 3 deletions(-)
 create mode 100644 src/main/kotlin/demos/coroutineDemo.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index 5931ffb..bb10686 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,3 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     kotlin("jvm") version "1.4.30"
 }
@@ -7,20 +5,27 @@ plugins {
 group = "ru.mipt.npm"
 version = "1.0"
 
+// Where to get dependencies
 repositories {
     mavenCentral()
 }
 
 dependencies {
+    //loading coroutines
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.3")
+
+    //testing libraries
     testImplementation(kotlin("test-junit5"))
     testImplementation("org.junit.jupiter:junit-jupiter-api:5.6.0")
     testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.6.0")
 }
 
+// Load testing platform
 tasks.test {
     useJUnitPlatform()
 }
 
-tasks.withType<KotlinCompile>() {
+// Set a byte-code target for JVM
+tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
     kotlinOptions.jvmTarget = "11"
 }
\ No newline at end of file
diff --git a/src/main/kotlin/demos/coroutineDemo.kt b/src/main/kotlin/demos/coroutineDemo.kt
new file mode 100644
index 0000000..c77375e
--- /dev/null
+++ b/src/main/kotlin/demos/coroutineDemo.kt
@@ -0,0 +1,36 @@
+package demos
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+
+suspend fun doASuspendedThing() {
+    delay(500)
+}
+
+suspend fun doASuspendedThingWithResult(): Int {
+    delay(500)
+    return 4
+}
+
+suspend fun main() {
+    //sequential coroutine
+    GlobalScope.launch {
+        doASuspendedThingWithResult()
+        // do a thing and do next thing when the result is there without blocking
+        doASuspendedThing()
+    }
+
+    //parallel coroutines
+    GlobalScope.launch(Dispatchers.Default) {
+        val job1 = launch {
+            doASuspendedThing()
+        }
+        val job2 = launch {
+            doASuspendedThing()
+        }
+        job1.join()
+        job2.join()
+    }
+}
\ No newline at end of file