refactor: 补充文档并优化代码

src/main/java/com/onixbyte/helix/client/TokenClient.java

@@ -5,6 +5,7 @@ import com.auth0.jwt.algorithms.Algorithm;
 import com.onixbyte.helix.domain.entity.User;
 import com.onixbyte.helix.properties.TokenProperties;
 import com.onixbyte.helix.utils.DateTimeUtil;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
 import java.time.LocalDateTime;
@@ -31,6 +32,7 @@ public class TokenClient {
      * @param tokenProperties the configuration properties for the token, such as issuer and
      *                        validity period
      */
+    @Autowired
     public TokenClient(Algorithm algorithm, TokenProperties tokenProperties) {
         this.algorithm = algorithm;
         this.tokenProperties = tokenProperties;

src/main/java/com/onixbyte/helix/controller/AssetController.java

@@ -6,6 +6,7 @@ import com.onixbyte.helix.exception.BizException;
 import com.onixbyte.helix.service.AssetService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
@@ -31,6 +32,7 @@ public class AssetController {
      *
      * @param assetService the file service to use for file operations
      */
+    @Autowired
     public AssetController(AssetService assetService) {
         this.assetService = assetService;
     }

src/main/java/com/onixbyte/helix/controller/AuthController.java

@@ -5,6 +5,7 @@ import com.onixbyte.helix.domain.web.response.LoginSuccessResponse;
 import com.onixbyte.helix.service.AuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
@@ -15,6 +16,7 @@ public class AuthController {
     private static final Logger log = LoggerFactory.getLogger(AuthController.class);
     private final AuthService authService;
 
+    @Autowired
     public AuthController(AuthService authService) {
         this.authService = authService;
     }

src/main/java/com/onixbyte/helix/controller/CaptchaController.java

@@ -2,6 +2,7 @@ package com.onixbyte.helix.controller;
 
 import com.onixbyte.helix.domain.web.response.CaptchaResponse;
 import com.onixbyte.helix.service.CaptchaService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -15,6 +16,7 @@ public class CaptchaController {
 
     private final CaptchaService captchaService;
 
+    @Autowired
     public CaptchaController(CaptchaService captchaService) {
         this.captchaService = captchaService;
     }

src/main/java/com/onixbyte/helix/controller/DepartmentController.java

@@ -3,6 +3,7 @@ package com.onixbyte.helix.controller;
 import com.onixbyte.helix.domain.entity.Department;
 import com.onixbyte.helix.domain.model.TreeNode;
 import com.onixbyte.helix.service.DepartmentService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
@@ -15,6 +16,7 @@ public class DepartmentController {
 
     private final DepartmentService departmentService;
 
+    @Autowired
     public DepartmentController(DepartmentService departmentService) {
         this.departmentService = departmentService;
     }

src/main/java/com/onixbyte/helix/controller/ExceptionController.java

@@ -37,7 +37,6 @@ import java.util.stream.Collectors;
 @RestControllerAdvice
 public class ExceptionController {
 
-
     /**
      * Handles business logic exceptions thrown throughout the application.
      * <p>

src/main/java/com/onixbyte/helix/controller/MenuController.java

@@ -3,6 +3,7 @@ package com.onixbyte.helix.controller;
 import com.onixbyte.helix.domain.entity.Menu;
 import com.onixbyte.helix.domain.model.TreeNode;
 import com.onixbyte.helix.service.MenuService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
@@ -15,6 +16,7 @@ public class MenuController {
 
     private final MenuService menuService;
 
+    @Autowired
     public MenuController(MenuService menuService) {
         this.menuService = menuService;
     }

src/main/java/com/onixbyte/helix/controller/PositionController.java

@@ -2,6 +2,7 @@ package com.onixbyte.helix.controller;
 
 import com.onixbyte.helix.domain.entity.Position;
 import com.onixbyte.helix.service.PositionService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
@@ -16,6 +17,7 @@ public class PositionController {
 
     private final PositionService positionService;
 
+    @Autowired
     public PositionController(PositionService positionService) {
         this.positionService = positionService;
     }

src/main/java/com/onixbyte/helix/controller/RoleController.java

@@ -5,6 +5,7 @@ import com.onixbyte.helix.domain.web.request.AddRoleRequest;
 import com.onixbyte.helix.domain.web.request.EditRoleRequest;
 import com.onixbyte.helix.domain.web.request.QueryRoleRequest;
 import com.onixbyte.helix.service.RoleService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
@@ -18,6 +19,7 @@ public class RoleController {
 
     private final RoleService roleService;
 
+    @Autowired
     public RoleController(RoleService roleService) {
         this.roleService = roleService;
     }

src/main/java/com/onixbyte/helix/controller/UserController.java

@@ -1,12 +1,12 @@
 package com.onixbyte.helix.controller;
 
-import com.onixbyte.helix.domain.entity.User;
 import com.onixbyte.helix.domain.web.request.AddUserRequest;
 import com.onixbyte.helix.domain.web.request.QueryUserRequest;
 import com.onixbyte.helix.domain.web.request.ResetPasswordRequest;
 import com.onixbyte.helix.domain.web.request.UpdateUserRequest;
 import com.onixbyte.helix.domain.web.response.UserDetailResponse;
 import com.onixbyte.helix.service.UserService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
@@ -21,6 +21,7 @@ public class UserController {
 
     private final UserService userService;
 
+    @Autowired
     public UserController(UserService userService) {
         this.userService = userService;
     }

src/main/java/com/onixbyte/helix/manager/ApplicationManager.java

@@ -1,6 +1,7 @@
 package com.onixbyte.helix.manager;
 
 import com.onixbyte.helix.properties.ApplicationProperties;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
 @Component
@@ -8,6 +9,7 @@ public class ApplicationManager {
 
     private final ApplicationProperties applicationProperties;
 
+    @Autowired
     public ApplicationManager(ApplicationProperties applicationProperties) {
         this.applicationProperties = applicationProperties;
     }

src/main/java/com/onixbyte/helix/manager/AssetManager.java

@@ -2,13 +2,12 @@ package com.onixbyte.helix.manager;
 
 import com.onixbyte.helix.constant.CacheName;
 import com.onixbyte.helix.domain.entity.Asset;
-import com.onixbyte.helix.exception.BizException;
 import com.onixbyte.helix.mapper.AssetMapper;
 import com.onixbyte.helix.repository.AssetRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.annotation.CacheEvict;
 import org.springframework.cache.annotation.CachePut;
 import org.springframework.cache.annotation.Cacheable;
-import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Component;
 
 @Component
@@ -17,6 +16,7 @@ public class AssetManager {
     private final AssetMapper assetMapper;
     private final AssetRepository assetRepository;
 
+    @Autowired
     public AssetManager(AssetMapper assetMapper, AssetRepository assetRepository) {
         this.assetMapper = assetMapper;
         this.assetRepository = assetRepository;

src/main/java/com/onixbyte/helix/manager/AuthorityManager.java

@@ -3,6 +3,7 @@ package com.onixbyte.helix.manager;
 import com.onixbyte.helix.constant.CacheName;
 import com.onixbyte.helix.domain.entity.Authority;
 import com.onixbyte.helix.mapper.AuthorityMapper;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.annotation.Cacheable;
 import org.springframework.stereotype.Component;
 
@@ -13,6 +14,7 @@ public class AuthorityManager {
 
     private final AuthorityMapper authorityMapper;
 
+    @Autowired
     public AuthorityManager(AuthorityMapper authorityMapper) {
         this.authorityMapper = authorityMapper;
     }

src/main/java/com/onixbyte/helix/manager/DepartmentManager.java

@@ -3,6 +3,7 @@ package com.onixbyte.helix.manager;
 import com.onixbyte.helix.domain.entity.Department;
 import com.onixbyte.helix.mapper.DepartmentMapper;
 import com.onixbyte.helix.repository.DepartmentRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Component;
@@ -15,6 +16,7 @@ public class DepartmentManager {
     private final DepartmentMapper departmentMapper;
     private final DepartmentRepository departmentRepository;
 
+    @Autowired
     public DepartmentManager(DepartmentMapper departmentMapper, DepartmentRepository departmentRepository) {
         this.departmentMapper = departmentMapper;
         this.departmentRepository = departmentRepository;

src/main/java/com/onixbyte/helix/manager/MenuManager.java

@@ -4,6 +4,7 @@ import com.onixbyte.helix.domain.entity.Menu;
 import com.onixbyte.helix.mapper.MenuMapper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
 import java.util.List;
@@ -13,6 +14,7 @@ public class MenuManager {
     private static final Logger log = LoggerFactory.getLogger(MenuManager.class);
     private final MenuMapper menuMapper;
 
+    @Autowired
     public MenuManager(MenuMapper menuMapper) {
         this.menuMapper = menuMapper;
     }

src/main/java/com/onixbyte/helix/manager/PositionManager.java

@@ -3,8 +3,8 @@ package com.onixbyte.helix.manager;
 import com.onixbyte.helix.domain.entity.Position;
 import com.onixbyte.helix.mapper.PositionMapper;
 import com.onixbyte.helix.repository.PositionRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
-import org.springframework.data.domain.PageImpl;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Component;
 
@@ -14,6 +14,7 @@ public class PositionManager {
     private final PositionMapper positionMapper;
     private final PositionRepository positionRepository;
 
+    @Autowired
     public PositionManager(PositionMapper positionMapper, PositionRepository positionRepository) {
         this.positionMapper = positionMapper;
         this.positionRepository = positionRepository;

src/main/java/com/onixbyte/helix/manager/RoleManager.java

@@ -1,11 +1,11 @@
 package com.onixbyte.helix.manager;
 
-import com.onixbyte.helix.constant.Status;
 import com.onixbyte.helix.domain.database.query.wrapper.QueryRoleWrapper;
 import com.onixbyte.helix.domain.entity.Role;
 import com.onixbyte.helix.exception.BizException;
 import com.onixbyte.helix.mapper.RoleMapper;
 import com.onixbyte.helix.repository.RoleRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.*;
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Component;
@@ -20,6 +20,7 @@ public class RoleManager {
     private final RoleMapper roleMapper;
     private final RoleRepository roleRepository;
 
+    @Autowired
     public RoleManager(RoleMapper roleMapper, RoleRepository roleRepository) {
         this.roleMapper = roleMapper;
         this.roleRepository = roleRepository;

src/main/java/com/onixbyte/helix/manager/SettingManager.java

@@ -2,6 +2,7 @@ package com.onixbyte.helix.manager;
 
 import com.onixbyte.helix.domain.entity.Setting;
 import com.onixbyte.helix.repository.SettingRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.annotation.Cacheable;
 import org.springframework.stereotype.Component;
 
@@ -10,6 +11,7 @@ public class SettingManager {
 
     private final SettingRepository settingRepository;
 
+    @Autowired
     public SettingManager(SettingRepository settingRepository) {
         this.settingRepository = settingRepository;
     }

src/main/java/com/onixbyte/helix/manager/UserManager.java

@@ -10,6 +10,7 @@ import com.onixbyte.helix.mapper.UserMapper;
 import com.onixbyte.helix.repository.UserRepository;
 import com.onixbyte.region.Region;
 import org.apache.commons.lang3.StringUtils;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.annotation.CachePut;
 import org.springframework.cache.annotation.Cacheable;
 import org.springframework.data.domain.Example;
@@ -30,7 +31,12 @@ public class UserManager {
     private final UserRepository userRepository;
     private final PasswordEncoder passwordEncoder;
 
-    public UserManager(UserMapper userMapper, UserRepository userRepository, PasswordEncoder passwordEncoder) {
+    @Autowired
+    public UserManager(
+            UserMapper userMapper,
+            UserRepository userRepository,
+            PasswordEncoder passwordEncoder
+    ) {
         this.userMapper = userMapper;
         this.userRepository = userRepository;
         this.passwordEncoder = passwordEncoder;

src/main/java/com/onixbyte/helix/manager/UserRoleManager.java

@@ -1,12 +1,11 @@
 package com.onixbyte.helix.manager;
 
 import com.onixbyte.helix.domain.entity.UserRole;
-import com.onixbyte.helix.exception.BizException;
 import com.onixbyte.helix.mapper.UserRoleMapper;
 import com.onixbyte.helix.repository.UserRoleRepository;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.springframework.http.HttpStatus;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
 import java.util.List;
@@ -18,6 +17,7 @@ public class UserRoleManager {
     private final UserRoleMapper userRoleMapper;
     private final UserRoleRepository userRoleRepository;
 
+    @Autowired
     public UserRoleManager(UserRoleMapper userRoleMapper, UserRoleRepository userRoleRepository) {
         this.userRoleMapper = userRoleMapper;
         this.userRoleRepository = userRoleRepository;

src/main/java/com/onixbyte/helix/manager/package-info.java

@@ -1,60 +0,0 @@
-/**
- * Business logic management and orchestration package for the Helix application.
- * <p>
- * This package is designed to contain manager classes that orchestrate complex business operations,
- * coordinate between multiple services, and handle cross-cutting concerns that span multiple
- * domain boundaries.
- * <p>
- * <strong>Manager Pattern:</strong> Managers in this package serve as facades or coordinators that
- * encapsulate complex business workflows, typically involving multiple services, repositories,
- * or external systems. They provide a higher-level abstraction over individual service components.
- * <p>
- * <strong>Intended Contents:</strong>
- * <ul>
- * <li>
- *   <strong>Workflow Managers:</strong> Orchestrate multi-step business processes
- * </li>
- * <li>
- *   <strong>Integration Managers:</strong> Coordinate interactions with external systems
- * </li>
- * <li>
- *   <strong>Transaction Managers:</strong> Handle complex transactional scenarios
- * </li>
- * <li>
- *   <strong>Cache Managers:</strong> Manage caching strategies and cache invalidation
- * </li>
- * <li>
- *   <strong>Event Managers:</strong> Coordinate event publishing and handling
- * </li>
- * </ul>
- * <p>
- * <strong>Design Guidelines:</strong>
- * <ul>
- * <li>
- *   <strong>Single Responsibility:</strong> Each manager should focus on a specific business domain
- *   or cross-cutting concern
- * </li>
- * <li>
- *   <strong>Service Coordination:</strong> Managers should delegate to services rather than
- *   implementing business logic directly
- * </li>
- * <li>
- *   <strong>Transaction Boundaries:</strong> Define clear transactional boundaries for
- *   complex operations
- * </li>
- * <li>
- *   <strong>Error Handling:</strong> Provide comprehensive error handling and rollback mechanisms
- *   for complex workflows
- * </li>
- * </ul>
- * <p>
- * Managers typically sit between the controller layer and the service layer, providing a
- * coordination point for complex operations that require multiple service interactions or
- * cross-cutting concerns.
- *
- * @author zihluwang
- * @since 1.0.0
- * @see com.onixbyte.helix.service
- * @see org.springframework.transaction.annotation.Transactional
- */
-package com.onixbyte.helix.manager;

src/main/java/com/onixbyte/helix/security/provider/UsernamePasswordAuthenticationProvider.java

@@ -7,6 +7,7 @@ import com.onixbyte.helix.manager.UserManager;
 import com.onixbyte.helix.security.authentication.UsernamePasswordAuthentication;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.security.authentication.AuthenticationProvider;
 import org.springframework.security.core.Authentication;
@@ -24,7 +25,12 @@ public class UsernamePasswordAuthenticationProvider implements AuthenticationPro
     private final PasswordEncoder passwordEncoder;
     private final AuthorityManager authorityManager;
 
-    public UsernamePasswordAuthenticationProvider(UserManager userManager, PasswordEncoder passwordEncoder, AuthorityManager authorityManager) {
+    @Autowired
+    public UsernamePasswordAuthenticationProvider(
+            UserManager userManager,
+            PasswordEncoder passwordEncoder,
+            AuthorityManager authorityManager
+    ) {
         this.userManager = userManager;
         this.passwordEncoder = passwordEncoder;
         this.authorityManager = authorityManager;

src/main/java/com/onixbyte/helix/service/AssetService.java

@@ -5,6 +5,7 @@ import com.onixbyte.helix.exception.BizException;
 import com.onixbyte.helix.manager.AssetManager;
 import com.onixbyte.helix.properties.AssetProperties;
 import com.onixbyte.helix.utils.SecurityUtil;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -34,6 +35,7 @@ public class AssetService {
     private final S3Client s3Client;
     private final AssetManager assetManager;
 
+    @Autowired
     public AssetService(
             AssetProperties assetProperties,
             S3Client s3Client,

src/main/java/com/onixbyte/helix/service/CaptchaService.java

@@ -51,14 +51,14 @@ public class CaptchaService {
             return null;
         }
 
-        // 生成 UUID 及验证码
+        // Generate UUID and captcha
         var uuid = UUID.randomUUID().toString().replaceAll("-", "");
         var captchaCode = producer.createText();
 
-        // 将验证码保存到缓存中
+        // Store UUID and captcha to cache
         captchaManager.setCaptcha(uuid, captchaCode);
 
-        // 生成验证码图片
+        // Generate captcha image
         var captchaImage = producer.createImage(captchaCode);
         try (var byteArrayOutputStream = new FastByteArrayOutputStream()) {
             ImageIO.write(captchaImage, FileType.Image.JPEG.getExtension(), byteArrayOutputStream);
@@ -69,8 +69,4 @@ public class CaptchaService {
             throw new BizException("无法生成验证码图片。");
         }
     }
-
-    public String getCaptcha(String uuid) {
-        return captchaManager.getCaptcha(uuid);
-    }
 }

src/main/java/com/onixbyte/helix/service/DepartmentService.java

@@ -4,7 +4,7 @@ import com.onixbyte.helix.domain.entity.Department;
 import com.onixbyte.helix.domain.model.TreeNode;
 import com.onixbyte.helix.manager.DepartmentManager;
 import com.onixbyte.helix.utils.TreeUtil;
-import org.springframework.data.domain.PageRequest;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 
@@ -15,6 +15,7 @@ public class DepartmentService {
 
     private final DepartmentManager departmentManager;
 
+    @Autowired
     public DepartmentService(DepartmentManager departmentManager) {
         this.departmentManager = departmentManager;
     }

src/main/java/com/onixbyte/helix/service/MenuService.java

@@ -7,6 +7,7 @@ import com.onixbyte.helix.utils.SecurityUtil;
 import com.onixbyte.helix.utils.TreeUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
@@ -16,6 +17,7 @@ public class MenuService {
     private static final Logger log = LoggerFactory.getLogger(MenuService.class);
     private final MenuManager menuManager;
 
+    @Autowired
     public MenuService(MenuManager menuManager) {
         this.menuManager = menuManager;
     }

src/main/java/com/onixbyte/helix/service/PositionService.java

@@ -2,17 +2,17 @@ package com.onixbyte.helix.service;
 
 import com.onixbyte.helix.domain.entity.Position;
 import com.onixbyte.helix.manager.PositionManager;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 
-import java.util.List;
-
 @Service
 public class PositionService {
 
     private final PositionManager positionManager;
 
+    @Autowired
     public PositionService(PositionManager positionManager) {
         this.positionManager = positionManager;
     }

src/main/java/com/onixbyte/helix/service/RoleService.java

@@ -9,6 +9,7 @@ import com.onixbyte.helix.domain.web.request.QueryRoleRequest;
 import com.onixbyte.helix.manager.RoleManager;
 import jakarta.transaction.Transactional;
 import org.apache.commons.lang3.StringUtils;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -20,6 +21,7 @@ public class RoleService {
 
     private final RoleManager roleManager;
 
+    @Autowired
     public RoleService(RoleManager roleManager) {
         this.roleManager = roleManager;
     }

src/main/java/com/onixbyte/helix/service/UserService.java

@@ -17,6 +17,7 @@ import com.onixbyte.helix.manager.UserManager;
 import com.onixbyte.helix.manager.UserRoleManager;
 import com.onixbyte.identitygenerator.IdentityGenerator;
 import org.apache.commons.collections4.CollectionUtils;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.security.crypto.password.PasswordEncoder;
@@ -36,6 +37,7 @@ public class UserService {
     private final PasswordEncoder passwordEncoder;
     private final ApplicationManager applicationManager;
 
+    @Autowired
     public UserService(
             UserManager userManager,
             IdentityGenerator<Long> userIdentityGenerator,

src/main/java/com/onixbyte/helix/utils/DateTimeUtil.java

@@ -4,8 +4,19 @@ import java.time.Instant;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
 
+/**
+ * DateTimeUtil helps to convert date and time between different types.
+ *
+ * @author zihluwang
+ */
 public class DateTimeUtil {
 
+    /**
+     * Convert {@link LocalDateTime} to {@link Instant}.
+     *
+     * @param localDateTime local date time to be converted
+     * @return converted instant
+     */
     public static Instant asInstant(LocalDateTime localDateTime) {
         return localDateTime.atZone(ZoneId.systemDefault())
                 .toInstant();

src/main/java/com/onixbyte/helix/utils/SecurityUtil.java

@@ -7,10 +7,24 @@ import org.slf4j.LoggerFactory;
 import org.springframework.http.HttpStatus;
 import org.springframework.security.core.context.SecurityContextHolder;
 
+/**
+ * SecurityUtil helps to manipulate Spring Security.
+ *
+ * @author zihluwang
+ */
 public class SecurityUtil {
 
     private static final Logger log = LoggerFactory.getLogger(SecurityUtil.class);
 
+    private SecurityUtil() {
+    }
+
+    /**
+     * Get user information from {@link SecurityContextHolder}.
+     *
+     * @return user information
+     * @throws BizException if user information is not saved in {@link SecurityContextHolder}
+     */
     public static User getCurrentUser() {
         var _details = SecurityContextHolder.getContext()
                 .getAuthentication()

src/main/java/com/onixbyte/helix/utils/TreeUtil.java

@@ -9,8 +9,16 @@ import org.springframework.http.HttpStatus;
 import java.util.*;
 import java.util.stream.Collectors;
 
+/**
+ * TreeUtil help to build a tree or forest of specified data.
+ *
+ * @author zihluwang
+ */
 public class TreeUtil {
 
+    private TreeUtil() {
+    }
+
     /**
      * Builds a tree from a flat list of items that implement Treeable.
      *
@@ -40,7 +48,7 @@ public class TreeUtil {
 
         // Get root item and build root node
         var rootItem = rootItems.get(0);
-        var rootNode = new TreeNode<T>(rootItem);
+        var rootNode = new TreeNode<>(rootItem);
         idToNodeMap.remove(rootItem.getId());
 
         // Iterate through all departments to build the hierarchy.