Data commit

Task/Chat-server/Kotlin/chat-server.kotlin

@@ -0,0 +1,153 @@
+import java.io.BufferedReader
+import java.io.IOException
+import java.io.InputStreamReader
+import java.io.OutputStreamWriter
+import java.io.Writer
+import java.net.ServerSocket
+import java.net.Socket
+import java.util.ArrayList
+import java.util.Collections
+
+class ChatServer private constructor(private val port: Int) : Runnable {
+    private val clients = ArrayList<Client>()
+
+    private val onlineListCSV: String
+        @Synchronized get() {
+            val sb = StringBuilder()
+            sb.append(clients.size).append(" user(s) online: ")
+            for (i in clients.indices) {
+                sb.append(if (i > 0) ", " else "").append(clients[i].clientName)
+            }
+            return sb.toString()
+        }
+
+    override fun run() {
+        try {
+            val ss = ServerSocket(port)
+            while (true) {
+                val s = ss.accept()
+                Thread(Client(s)).start()
+            }
+        } catch (e: Exception) {
+            e.printStackTrace()
+        }
+    }
+
+    @Synchronized
+    private fun registerClient(client: Client): Boolean {
+        for (otherClient in clients) {
+            if (otherClient.clientName!!.equals(client.clientName!!, ignoreCase = true)) {
+                return false
+            }
+        }
+        clients.add(client)
+        return true
+    }
+
+    private fun deRegisterClient(client: Client) {
+        var wasRegistered = false
+        synchronized(this) {
+            wasRegistered = clients.remove(client)
+        }
+        if (wasRegistered) {
+            broadcast(client, "--- " + client.clientName + " left ---")
+        }
+    }
+
+    private fun broadcast(fromClient: Client, msg: String) {
+        // Copy client list (don't want to hold lock while doing IO)
+        var clients: List<Client> = Collections.emptyList()
+        synchronized(this) {
+            clients = ArrayList(this.clients)
+        }
+        for (client in clients) {
+            if (client.equals(fromClient)) {
+                continue
+            }
+            try {
+                client.write(msg + "\r\n")
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+
+        }
+    }
+
+    inner class Client internal constructor(private var socket: Socket?) : Runnable {
+        private var output: Writer? = null
+        var clientName: String? = null
+
+        override fun run() {
+            try {
+                socket!!.sendBufferSize = 16384
+                socket!!.tcpNoDelay = true
+                val input = BufferedReader(InputStreamReader(socket!!.getInputStream()))
+                output = OutputStreamWriter(socket!!.getOutputStream())
+                write("Please enter your name: ")
+                var line: String
+                while (true) {
+                    line = input.readLine()
+                    if (null == line) {
+                        break
+                    }
+                    if (clientName == null) {
+                        line = line.trim { it <= ' ' }
+                        if (line.isEmpty()) {
+                            write("A name is required. Please enter your name: ")
+                            continue
+                        }
+                        clientName = line
+                        if (!registerClient(this)) {
+                            clientName = null
+                            write("Name already registered. Please enter your name: ")
+                            continue
+                        }
+                        write(onlineListCSV + "\r\n")
+                        broadcast(this, "+++ $clientName arrived +++")
+                        continue
+                    }
+                    if (line.equals("/quit", ignoreCase = true)) {
+                        return
+                    }
+                    broadcast(this, "$clientName> $line")
+                }
+            } catch (e: Exception) {
+                e.printStackTrace()
+            } finally {
+                deRegisterClient(this)
+                output = null
+                try {
+                    socket!!.close()
+                } catch (e: Exception) {
+                    e.printStackTrace()
+                }
+
+                socket = null
+            }
+        }
+
+        @Throws(IOException::class)
+        internal fun write(msg: String) {
+            output!!.write(msg)
+            output!!.flush()
+        }
+
+        internal fun equals(client: Client?): Boolean {
+            return (client != null
+                && clientName != null
+                && client.clientName != null
+                && clientName == client.clientName)
+        }
+    }
+
+    companion object {
+        @JvmStatic
+        fun main(args: Array<String>) {
+            var port = 4004
+            if (args.isNotEmpty()) {
+                port = Integer.parseInt(args[0])
+            }
+            ChatServer(port).run()
+        }
+    }
+}