add drill03 exercise 2 & 3

src/main/kotlin/drills/drill03/exercise2/Agent.kt

@@ -0,0 +1,18 @@
+package drills.drill03.exercise2
+
+import java.io.Serializable
+
+interface Agent : Serializable, Runnable {
+    fun start()
+    fun migrateTo(node: Node)
+}
+
+abstract class AbstractAgent : Agent {
+    override fun start() {
+        Thread(this).start()
+    }
+
+    override fun migrateTo(node: Node) {
+        node.migrate(this)
+    }
+}

src/main/kotlin/drills/drill03/exercise2/AgentContainer.kt

@@ -0,0 +1,16 @@
+package drills.drill03.exercise2
+
+import java.rmi.Remote
+import java.rmi.RemoteException
+import java.rmi.server.UnicastRemoteObject
+
+interface AgentContainer : Remote {
+    @Throws(RemoteException::class)
+    fun migrate(agent: Agent)
+}
+
+class AgentContainerImpl : AgentContainer, UnicastRemoteObject() {
+    override fun migrate(agent: Agent) {
+        agent.start()
+    }
+}

src/main/kotlin/drills/drill03/exercise2/ContainerServer.kt

@@ -0,0 +1,26 @@
+package drills.drill03.exercise2
+
+import java.net.MalformedURLException
+import java.rmi.AccessException
+import java.rmi.AlreadyBoundException
+import java.rmi.Naming
+import java.rmi.RemoteException
+import java.rmi.registry.LocateRegistry
+
+fun main(args: Array<String>) {
+    try {
+        if (args[0] == "0")
+            LocateRegistry.createRegistry(4242)
+
+        val container: AgentContainer = AgentContainerImpl()
+        Naming.rebind("rmi://localhost:4242/container-${args[0]}", container)
+    } catch (e: AccessException) {
+        System.err.println("Bind operation not permitted $e")
+    } catch (e: RemoteException) {
+        System.err.println("Registry could not be contacted $e")
+    } catch (e: MalformedURLException) {
+        System.err.println("Wrong URL for binding $e")
+    } catch (e: AlreadyBoundException) {
+        System.err.println("Object alreay bound to the registry $e")
+    }
+}

src/main/kotlin/drills/drill03/exercise2/Node.kt

@@ -0,0 +1,36 @@
+package drills.drill03.exercise2
+
+import java.io.Serializable
+import java.net.MalformedURLException
+import java.rmi.Naming
+import java.rmi.NotBoundException
+import java.rmi.RemoteException
+
+interface Node : Serializable {
+    fun migrate(agent: Agent)
+}
+
+class NodeImpl(index: Int) : Node {
+    private val container = getContainer(index)
+
+    override fun migrate(agent: Agent) {
+        container?.migrate(agent)
+    }
+
+    private fun getContainer(index: Int): AgentContainer? {
+        try {
+            return Naming
+                .lookup("rmi://localhost:4242/container-$index") as AgentContainer
+        } catch (e: NotBoundException) {
+            System.err.println("Request obect not bound $e")
+        } catch (e: MalformedURLException) {
+            System.err.println("Wrong URL $e")
+        } catch (e: RemoteException) {
+            System.err.println("Network or Server Error $e")
+        } catch (e: Exception) {
+            System.err.println("Generic Error $e")
+        }
+
+        return null
+    }
+}

src/main/kotlin/drills/drill03/exercise2/PrintAgent.kt

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+package drills.drill03.exercise2
+
+class PrintAgent(private val nodes: Array<Node>): AbstractAgent(){
+    private var index = 0
+    private val names = mutableListOf<String>()
+
+    override fun run() {
+        if (index < nodes.size) {
+            println("Insert your name:")
+            val name = readLine() ?: "no name"
+            names.add(name)
+            migrateTo(nodes[index++])
+        } else
+            println(names)
+    }
+}

src/main/kotlin/drills/drill03/exercise2/PrintApp.kt

@@ -0,0 +1,7 @@
+package drills.drill03.exercise2
+
+fun main() {
+    val nodes = Array<Node>(3) { NodeImpl(it) }
+
+    PrintAgent(nodes).start()
+}

src/main/kotlin/drills/drill03/exercise3/AddTask.kt

@@ -0,0 +1,7 @@
+package drills.drill03.exercise3
+
+import java.io.Serializable
+
+class AddTask(private val a: Int, private val b: Int) : Task {
+    override fun execute(): Serializable = a + b
+}

src/main/kotlin/drills/drill03/exercise3/Client.kt

@@ -0,0 +1,26 @@
+package drills.drill03.exercise3
+
+import util.rmi.Client
+
+fun main() {
+    Client(clientHandler).start()
+}
+
+val clientHandler = {
+    val rev = Client.lookup("rev") as Rev
+
+    println("Enter two numbers:")
+    val a = readLine()?.toInt() ?: 0
+    val b = readLine()?.toInt() ?: 0
+
+    val sum = rev.executeTask(AddTask(a, b))
+    println("The sum of $a and $b is $sum")
+
+    println("Enter the number of which you want to calculate the factorial:")
+    val n = readLine()?.toInt() ?: 0
+
+    val fact = rev.executeTask(FactTask(n))
+    println("The factorial of $n is $fact")
+}
+
+fun fact(n: Int): Long = if (n <= 1) 1 else n * fact(n - 1)

src/main/kotlin/drills/drill03/exercise3/FactTask.kt

@@ -0,0 +1,9 @@
+package drills.drill03.exercise3
+
+import java.io.Serializable
+
+class FactTask(private val n: Int) : Task {
+    override fun execute(): Serializable = fact(n)
+
+    private fun fact(n: Int): Long = if (n <= 1) 1 else n * fact(n - 1)
+}

src/main/kotlin/drills/drill03/exercise3/Rev.kt

@@ -0,0 +1,15 @@
+package drills.drill03.exercise3
+
+import java.io.Serializable
+import java.rmi.Remote
+import java.rmi.RemoteException
+import java.rmi.server.UnicastRemoteObject
+
+interface Rev : Remote {
+    @Throws(RemoteException::class)
+    fun executeTask(task: Task): Serializable
+}
+
+class RevImpl : Rev, UnicastRemoteObject() {
+    override fun executeTask(task: Task): Serializable = task.execute()
+}

src/main/kotlin/drills/drill03/exercise3/Server.kt

@@ -0,0 +1,11 @@
+package drills.drill03.exercise3
+
+import util.rmi.Server
+
+fun main() {
+    Server {
+        System.setSecurityManager(SecurityManager())
+        val rev: Rev = RevImpl()
+        Server.bind(rev, "rev")
+    }.start()
+}

src/main/kotlin/drills/drill03/exercise3/Task.kt

@@ -0,0 +1,7 @@
+package drills.drill03.exercise3
+
+import java.io.Serializable
+
+interface Task : Serializable {
+    fun execute(): Serializable
+}