Moved functionality of sending and receiving messages to and from server into separate threads.

src/main/java/connect/src/Client.java

@@ -7,7 +7,7 @@ import data.src.ControllerToConnectionClient.ControllerToConnectionClientData;
 
 public interface Client {
     public boolean createConnection(ControllerToConnectionClientData controllerToConnectionClientData);
-    public void sendData(String data);
-    public void receiveData();
+    public void startSender();
+    public void startReceiver();
     public void closeConnection();
 }

src/main/java/connect/src/Receiver.java

@@ -0,0 +1,59 @@
+/**
+ * @author Aaron Moser
+ * @date 26.12.2023
+ */
+package connect.src;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+import queues.src.ReceivingQueue;
+
+public class Receiver extends Thread {
+    private static Receiver instance = null;
+
+    private boolean receiverRunning = false;
+
+    BufferedReader reader = null;
+
+    private Receiver() {}
+
+    public static Receiver getInstance() {
+        if (instance == null) {
+            instance = new Receiver();
+        }
+        return instance;
+    }
+
+    @Override
+    public void run() {
+        receiverRunning = true;
+        while (receiverRunning) {
+            receiveData();
+        }
+    }
+
+    public void receiveData() {
+        try {
+            if (TLSClient.getSSLSocket().isConnected()) {
+                if (reader == null) {
+                    reader = new BufferedReader(new InputStreamReader(TLSClient.getSSLSocket().getInputStream()));
+                }
+                if (reader != null) {
+                    String response;
+                    while ((response = reader.readLine()) != null) {
+                        //System.out.println(response);
+                        ReceivingQueue.getInstance().add(response);
+                    }
+                }
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public void stopThread() {
+        this.receiverRunning = false;
+    }
+}

src/main/java/connect/src/Sender.java

@@ -0,0 +1,73 @@
+/**
+ * @author Aaron Moser
+ * @date 26.12.2023
+ */
+package connect.src;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import javax.net.ssl.SSLSocket;
+
+import queues.src.SendingQueue;
+
+/**
+ * TODO change pattern from singleton to dependency injection.
+ */
+public class Sender extends Thread {
+    private static Sender instance = null;
+
+    private boolean senderRunning = false;
+
+    private PrintWriter writer = null;
+
+    private Sender() {}
+
+    public static Sender getInstance() {
+        if (instance == null) {
+            instance = new Sender();
+        }
+        return instance;
+    }
+
+    @Override
+    public void run() {
+        senderRunning = true;
+        while (senderRunning) {
+            try {
+                // Wait until controller puts requests into sending queue.
+                String item = SendingQueue.getInstance().take();
+                System.out.println("Sender sends: " + item);
+                sendData(item);
+            } catch (InterruptedException e) {
+                System.out.println("Sender thread was interrupted.");
+                Thread.currentThread().interrupt();
+                return;
+            }
+        }
+    }
+
+    private void sendData(String data) {
+        try {
+            if (TLSClient.getSSLSocket().isConnected()) {
+                if (writer == null) {
+                    writer = new PrintWriter(TLSClient.getSSLSocket().getOutputStream());
+                }
+                if (writer != null && data !=  null) {
+                    writer.println(data);
+                    writer.flush();
+                } else {
+                    System.out.println("Connection is not established.");
+                }
+            } else {
+                System.out.println("SSLSocket is null.");
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public void stopThread() {
+        this.senderRunning = false;
+    }
+}

src/main/java/connect/src/TLSClient.java

@@ -6,7 +6,6 @@ package connect.src;
 import java.io.BufferedReader;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.io.InputStreamReader;
 import java.io.PrintWriter;
 
 import java.net.UnknownHostException;
@@ -27,9 +26,11 @@ import data.src.ControllerToConnectionClient.ControllerToConnectionClientData;
 
 public final class TLSClient implements Client {
 
-    private SSLSocket sslSocket;
-    private BufferedReader reader;
-    private PrintWriter writer;
+    private static SSLSocket sslSocket;
+
+    public static synchronized SSLSocket getSSLSocket() {
+        return sslSocket;
+    }
 
     public boolean createConnection(ControllerToConnectionClientData controllerToConnectionClientData) {
         try {
@@ -76,56 +77,21 @@ public final class TLSClient implements Client {
         }
     }
 
-    public void sendData(String data) {
-        try {
-            writer = new PrintWriter(sslSocket.getOutputStream());
-            if (sslSocket != null && sslSocket.isConnected() && writer != null) {
-                writer.println("Hello Server!");
-                writer.flush();
-                if (null != data) {
-                    writer.println(data);
-                    writer.flush();
-                }
-            } else {
-                System.out.println("Connection is not established.");
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
+    public void startSender() {
+        Sender.getInstance().start();
     }
 
-    public void receiveData() {
-        try {
-            reader = new BufferedReader(new InputStreamReader(sslSocket.getInputStream()));
-            if (null != reader) {
-                String response;
-                while ((response = reader.readLine()) != null) {
-                    System.out.println(response);
-                }
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
+    public void startReceiver() {
+        Receiver.getInstance().start();
     }
 
     public void closeConnection() {
         try {
-            if (null != reader) {
-                reader.close();
-            }
-            if (null != writer) {
-                writer.close();
+            if (sslSocket != null) {
+                sslSocket.close();
             }
         } catch (IOException e) {
             e.printStackTrace();
-        } finally {
-            try {
-                if (null != sslSocket) {
-                    sslSocket.close();
-                }
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
         }
     }
 }