Add: TcpTransport class to implement TransportLayer

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/network/TcpTransport.java

@@ -0,0 +1,37 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.network;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+
+public class TcpTransport implements TransportLayer {
+    private Socket socket;
+    private DataInputStream in;
+    private DataOutputStream out;
+
+    public TcpTransport(Socket socket) throws IOException {
+        this.socket = socket;
+        this.in = new DataInputStream(socket.getInputStream());
+        this.out = new DataOutputStream(socket.getOutputStream());
+    }
+
+    public String read() throws IOException {
+        int length = in.readInt();
+        byte[] payload = new byte[length];
+        in.readFully(payload);
+        return new String(payload, StandardCharsets.UTF_8);
+    }
+
+    public void write(String payload) throws IOException {
+        byte[] rawPayload = payload.getBytes(StandardCharsets.UTF_8);
+        out.writeInt(rawPayload.length);
+        out.write(rawPayload);
+        out.flush();    
+    }
+
+    public void close() throws IOException {
+        socket.close();
+    }
+}