add javadocs for userservice

src/main/java/com/cloudcomputing/todo/service/UserService.java

@@ -35,10 +35,15 @@ public class UserService {
     @Autowired
     private TodoRepository todoRepository;
 
+
+    /**
+     * @param userDTO the data transfer object containing user details
+     * @return the created userDTO or null if user already exists
+     */
     public UserDTO createUser(UserDTO userDTO) {
         User newUser;
 
-        if(!(userRepository.existsByUserId(userDTO.getUserId()) || userRepository.existsByUserName(userDTO.getUserName()))){
+        if (!(userRepository.existsByUserId(userDTO.getUserId()) || userRepository.existsByUserName(userDTO.getUserName()))) {
             newUser = userMapper.dtoToEntity(userDTO);
             return userMapper.entityToDto(userRepository.save(newUser));
         }
@@ -46,12 +51,21 @@ public class UserService {
         return null;
     }
 
+    /**
+     * @param userDTO the data transfer object containing user details
+     * @return the userDTO with the given username
+     */
     public UserDTO getUser(UserDTO userDTO) {
         return userMapper.entityToDto(userRepository.findByUserName(userDTO.getUserName()));
     }
 
+    /**
+     * @param request the request from the frontend which includes the jsessionid
+     * @param userDTO the data transfer object containing user details
+     * @return boolean value which indicates if the login was successful or not
+     */
     public boolean login(HttpServletRequest request, UserDTO userDTO) {
-        if(customAuthenticator.authenticate(userDTO)){
+        if (customAuthenticator.authenticate(userDTO)) {
             String userId = userRepository.findByUserName(userDTO.getUserName()).getUserId();
             HttpSession session = request.getSession();
             session.setAttribute("userId", userId);
@@ -61,18 +75,27 @@ public class UserService {
         return false;
     }
 
+    /**
+     * @param request the request from the frontend which includes the jsessionid
+     * @param userId  the id of the currently logged-in user
+     * @return true to indicate successful logout
+     */
     public boolean logout(HttpServletRequest request, String userId) {
         HttpSession session = request.getSession();
 
-        if(session != null){
+        if (session != null) {
             session.invalidate();
         }
 
         return true;
     }
 
+    /**
+     * @param userId the id of the currently logged-in user
+     * @return list of todoDTOs
+     */
     public List<TodoDTO> getAllTodos(String userId) {
-        List <Todo> todoList = todoRepository.findAllByUserId(userId);
+        List<Todo> todoList = todoRepository.findAllByUserId(userId);
         List<TodoDTO> todoDTOList = new ArrayList<>();
 
         todoList.forEach((todoItem) -> {
@@ -81,22 +104,36 @@ public class UserService {
         return todoDTOList;
     }
 
-    public List<TodoDTO> addTodo(TodoDTO todoDTO){
+    /**
+     * @param todoDTO data transfer object that contains details about a todoElement
+     * @return a list of all todos for the given user
+     */
+    public List<TodoDTO> addTodo(TodoDTO todoDTO) {
         Todo todo = todoMapper.dtoToEntity(todoDTO);
         todoRepository.save(todo);
 
         return getAllTodosForUser(todoDTO.getUserId());
     }
 
+    /**
+     * @param userId the id of the currently logged-in user
+     * @param todoId id of the todo that will be deleted
+     * @return a list of all todos for the given user
+     */
     public List<TodoDTO> deleteTodo(String userId, String todoId) {
         System.out.println("service here");
-        if(todoRepository.existsById(todoId)){
+        if (todoRepository.existsById(todoId)) {
             todoRepository.deleteById(todoId);
         }
 
         return getAllTodosForUser(userId);
     }
 
+    /**
+     * @param userId the id of the currently logged-in user
+     * @param todoId id of the todo that will be set to complete
+     * @return a list of all todos for the given user
+     */
     public List<TodoDTO> setTodoComplete(String userId, String todoId) {
         Todo todo = todoRepository.findById(todoId).get();
         todo.setCompleted(true);
@@ -105,14 +142,24 @@ public class UserService {
         return getAllTodosForUser(userId);
     }
 
-    //helper methods
+    /*****************
+     * HELPER METHODS *
+     *****************/
 
+    /**
+     * @param request the request from the frontend which includes the jsessionid
+     * @return boolean that indicates if the session is valid or not
+     */
     public boolean validateSession(HttpServletRequest request) {
         HttpSession session = request.getSession(false);
         System.out.println("Session ID: " + (session != null ? session.getId() : "null"));
         return session != null && session.getAttribute("userId") != null;
     }
 
+    /**
+     * @param userId the id of the user for which all todos should be retrieved
+     * @return a list of all the todoDTOs for the given user
+     */
     public List<TodoDTO> getAllTodosForUser(String userId) {
         List<Todo> todoList = todoRepository.findAllByUserId(userId);
         List<TodoDTO> todoDTOList = new ArrayList<>();