fix drill-01 exercise-4

The server executes the factorial asynchronously

build.gradle.kts

@@ -19,6 +19,7 @@ group = "it.norangeb.unisannio"
 
 dependencies {
     implementation(kotlin("stdlib-jdk8"))
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.5")
     testCompile("junit", "junit", "4.12")
     detektPlugins("io.gitlab.arturbosch.detekt:detekt-formatting:1.7.0-beta2")
 }

src/main/kotlin/drills/drill01/exercise4/Client.kt

@@ -20,4 +20,7 @@ val clientHandler = {
     sps.print("The factorial of $n is $fact")
 
     math.getFactOf(n, aps)
+
+    for (i in 0 until 500)
+        println("other work...")
 }

src/main/kotlin/drills/drill01/exercise4/Math.kt

@@ -1,6 +1,8 @@
 package drills.drill01.exercise4
 
 import drills.drill01.exercise2.PrintService
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
 import java.rmi.Remote
 import java.rmi.RemoteException
 import java.rmi.server.UnicastRemoteObject
@@ -17,7 +19,9 @@ class MathImpl : Math, UnicastRemoteObject() {
     override fun getFactOf(n: Int): Long = fact(n)
 
     override fun getFactOf(n: Int, ps: PrintService) {
-        ps.print("The factorial of $n is ${fact(n)}")
+        GlobalScope.launch {
+            ps.print("The factorial of $n is ${fact(n)}")
+        }
     }
 
     private fun fact(n: Int): Long {

src/main/kotlin/drills/drill01/exercise4/Server.kt

@@ -4,8 +4,7 @@ import util.rmi.Server
 
 fun main() {
     Server {
-        val math: Math =
+        val math: Math = MathImpl()
-            MathImpl()
         Server.bind(math, "math")
     }.start()
 }