Added garbage collection for disconnected players

- Heartbeat messages are sent out from their own thread to each player
- If a heartbeat message can't be sent to a player, they are removed from the list of players
- Added equals method for players
Tags: #story[1047]

src/main/java/seng302/gameServer/ClientConnectionDelegate.java

@@ -3,5 +3,15 @@ package seng302.gameServer;
 import seng302.models.Player;
 
 public interface ClientConnectionDelegate {
+    /**
+     * A player has connected to the server
+     * @param player The player that has connected
+     */
     void clientConnected(Player player);
+
+    /**
+     * A player has disconnected from the server
+     * @param player The player that has disconnected
+     */
+    void clientDisconnected(Player player);
 }

src/main/java/seng302/gameServer/GameServerThread.java

@@ -26,7 +26,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
     private long startTime;
     private short seqNum;
     
-    private final int HEARTBEAT_PERIOD = 5000;
     private final int RACE_STATUS_PERIOD = 1000/2;
     private final int RACE_START_STATUS_PERIOD = 1000;
     private final int BOAT_LOCATION_PERIOD = 1000/5;
@@ -128,28 +127,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
                 100, GameState.getPlayers().size(), RaceType.MATCH_RACE, 1, boatSubMessages);
     }
 
-
-    /**
-     * Starts sending heartbeat messages to the client
-     */
-    private void startSendingHeartbeats() {
-        Timer t = new Timer();
-
-        t.schedule(new TimerTask() {
-            @Override
-            public void run() {
-                Message heartbeat = new Heartbeat(seqNum);
-
-                try {
-                    System.out.println("Sending heartbeat");
-                    broadcast(heartbeat);
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            }
-        }, 0, HEARTBEAT_PERIOD);
-    }
-
     /**
      * Start sending race start status messages until race starts
      */
@@ -164,7 +141,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
                     if (startTime < System.currentTimeMillis() && GameState.getCurrentStage() != GameStages.RACING){
                     }
                     else{
-                        System.out.println("Sending race start status");
                         broadcast(raceStartStatusMessage);
                     }
 
@@ -204,15 +180,12 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
             Message regatta = getXmlMessage("/server_config/regatta.xml", XMLMessageSubType.REGATTA);
 
             if (raceData != null){
-                System.out.println("Sending RaceXML");
                 broadcast(raceData);
             }
             if (boatData != null){
-                System.out.println("Sending boatsXML");
                 broadcast(boatData);
             }
              if (regatta != null){
-                 System.out.println("Sending regattaXML");
                  broadcast(regatta);
             }
         } catch (IOException e) {
@@ -231,7 +204,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
                 try {
                     Message raceData = getXmlMessage("/server_config/courseLimits.xml", XMLMessageSubType.RACE);
                     if (raceData != null) {
-                        System.out.println("Sending courseLimitsXML");
                         broadcast(raceData);
                     }
                 }catch (IOException e) {
@@ -244,12 +216,17 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
 
     public void run() {
         ServerListenThread serverListenThread;
+        HeartbeatThread heartbeatThread;
         Boolean serverIsSendingMessages = false;
 
         try{
             server = ServerSocketChannel.open();
             server.socket().bind(new InetSocketAddress("localhost", PORT_NUMBER));
+
             serverListenThread = new ServerListenThread(server, this);
+            heartbeatThread = new HeartbeatThread(this);
+
+            heartbeatThread.start();
             serverListenThread.start();
         }
         catch (IOException e){
@@ -266,7 +243,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
             if (GameState.getCurrentStage() == GameStages.RACING && !serverIsSendingMessages) {
                 serverLog("Race Started", 0);
 
-                startSendingHeartbeats();
                 sendXml();
                 startSendingRaceStartStatusMessages();
                 //startSendingRaceStatusMessages();
@@ -279,7 +255,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
             }
 
             startTime = System.currentTimeMillis() + TIME_TILL_RACE_START;
-
             }
     }
 
@@ -314,44 +289,35 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
     @Override
     public void clientConnected(Player player) {
         if (GameState.getPlayers().size() < MAX_NUM_PLAYERS && GameState.getCurrentStage() == GameStages.LOBBYING) {
-            System.out.println("");
             serverLog("Player Connected", 0);
             GameState.addPlayer(player);
-        }
             sendXml();
         }
+    }
 
     /**
-     * Listens for a connection and upon finding one, creates a Player object and adds it to the universal GameState
+     * A player has left the game, remove the player from the GameState
+     * @param player The player that left
      */
-    private void acceptConnection() {
+    @Override
-        try {
+    public void clientDisconnected(Player player) {
-            SocketChannel thisClient = server.accept();
+        serverLog("Player disconnected", 0);
-            if (thisClient.socket() != null){
+        GameState.removePlayer(player);
-                Player thisPlayer = new Player(thisClient);
+        sendXml();
-                GameState.addPlayer(thisPlayer);
     }
-        } catch (IOException e) {
-            e.getMessage();
-        }
-    }
-
 
     void unicast(Message message, SocketChannel client) throws IOException {
-        message.send(client);       // TODO: 11/07/17 Do we incement seqNum for individual messages? 
+        message.send(client);
     }
 
-
     void broadcast(Message message) throws IOException{
         for(Player player : GameState.getPlayers()) {
-            System.out.println("Sending message seqNo[" + seqNum + "] to Player: " + player.toString());
+            //System.out.println("Sending message seqNo[" + seqNum + "] to Player: " + player.toString());
             message.send(player.getSocketChannel());
         }
-        seqNum++;       // TODO: 11/07/17 Do we increment seqNum for every message or for the one message to everyone 
+        seqNum++;
     }
 
-
-    
     /**
      * Send a boat location message when they are updated by the simulator
      * @param o .
@@ -388,8 +354,6 @@ public class GameServerThread implements Runnable, Observer, ClientConnectionDel
             }*/
         }
 
-
-
 //        if (numOfBoatsFinished == ((List<Boat>) arg).size()) {
 //            startSendingRaceFinishedBoatPositions();
 //        }

src/main/java/seng302/gameServer/HeartbeatThread.java

@@ -0,0 +1,81 @@
+package seng302.gameServer;
+
+import seng302.models.Player;
+import seng302.server.messages.Heartbeat;
+import seng302.server.messages.Message;
+
+import java.io.IOException;
+import java.util.*;
+
+/**
+ * Send Heartbeat messages to connected player at a specified interval
+ * Will call .clientDisconnected on the delegate when a heartbeat message
+ * cannot be sent to a player
+ */
+public class HeartbeatThread extends Thread{
+    private final int HEARTBEAT_PERIOD = 5000;
+    private ClientConnectionDelegate delegate;
+    private Integer seqNum;
+    private Stack<Player> disconnectedPlayers;
+
+    HeartbeatThread(ClientConnectionDelegate delegate){
+        this.delegate =  delegate;
+        seqNum = 0;
+        disconnectedPlayers = new Stack<>();
+    }
+
+    /**
+     * A player has lost connection to the server
+     * The player is added to a stack so that the delegate
+     * can be notified
+     *
+     * @param player The player that has disconnected
+     */
+    private void playerLostConnection(Player player){
+        disconnectedPlayers.push(player);
+    }
+
+    /**
+     * Sends a heartbeat message to each connected player
+     * The delegate is notified if a player has disconnected
+     */
+    private void sendHeartbeatToAllPlayers(){
+        Message heartbeat = new Heartbeat(seqNum);
+
+        for (Player player : GameState.getPlayers()){
+            if (!player.getSocketChannel().isConnected()){
+                playerLostConnection(player);
+            }
+
+            try {
+                heartbeat.send(player.getSocketChannel());
+            } catch (IOException e) {
+                playerLostConnection(player);
+            }
+        }
+
+        updateDelegate();
+        seqNum++;
+    }
+
+    /**
+     * Notifies the delegate about
+     * each disconnected player
+     */
+    private void updateDelegate() {
+        while (!disconnectedPlayers.empty()){
+            delegate.clientDisconnected(disconnectedPlayers.pop());
+        }
+    }
+
+    public void run(){
+        Timer t = new Timer();
+
+        t.schedule(new TimerTask() {
+            @Override
+            public void run() {
+                sendHeartbeatToAllPlayers();
+            }
+        }, 0, HEARTBEAT_PERIOD);
+    }
+}

src/main/java/seng302/gameServer/ServerListenThread.java

@@ -1,6 +1,5 @@
 package seng302.gameServer;
 
-import com.sun.corba.se.spi.activation.Server;
 import seng302.models.Player;
 
 import java.io.IOException;
@@ -15,7 +14,7 @@ public class ServerListenThread extends Thread{
     private ServerSocketChannel socketChannel;
     private ClientConnectionDelegate delegate;
 
-    public ServerListenThread(ServerSocketChannel socketChannel, ClientConnectionDelegate delegate){
+    ServerListenThread(ServerSocketChannel socketChannel, ClientConnectionDelegate delegate){
         this.socketChannel = socketChannel;
         this.delegate = delegate;
     }

src/main/java/seng302/models/Player.java

@@ -24,7 +24,6 @@ public class Player {
         return socketChannel;
     }
 
-
     public Integer getLastMarkPassed() {
         return lastMarkPassed;
     }
@@ -40,6 +39,11 @@ public class Player {
     @Override
     public String toString() {
         String playerAddress = null;
+
+        if (socketChannel == null){
+            return "Disconnected Player";
+        }
+
         try {
             playerAddress = socketChannel.getRemoteAddress().toString();
         } catch (IOException e) {
@@ -48,4 +52,22 @@ public class Player {
 
         return playerAddress;
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null){
+            return false;
+        }
+
+        if (!(obj instanceof Player)){
+            return false;
+        }
+
+        return ((Player) obj).socketChannel.equals(socketChannel);
+    }
+
+    @Override
+    public int hashCode(){
+        return socketChannel.hashCode();
+    }
 }

src/main/java/seng302/server/messages/RaceStartStatusMessage.java

@@ -54,6 +54,15 @@ public class RaceStartStatusMessage extends Message {
         writeCRC();
         rewind();
 
+        if (outputStream == null){
+            return;
+        }
+
+        try{
             outputStream.write(getBuffer());
         }
+        catch (IOException e){
+            return;
+        }
+    }
 }