refactoring and documentation of the latest code updates

src/main/java/com/java_school/final_task/configuration/JPAQueryFactoryConfig.java

@@ -6,8 +6,18 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
+/**
+ * Configuration class for setting up JPAQueryFactory bean.
+ * Provides bean definitions for creating and configuring JPAQueryFactory instances.
+ */
 @Configuration
 public class JPAQueryFactoryConfig {
+    /**
+     * Configures and provides a JPAQueryFactory bean.
+     *
+     * @param entityManager The EntityManager instance to be injected into the JPAQueryFactory.
+     * @return JPAQueryFactory A configured bean of JPAQueryFactory that integrates with JPA.
+     */
     @Bean
     public JPAQueryFactory jpaQueryFactory(@Autowired EntityManager entityManager) {
         return new JPAQueryFactory(entityManager);

src/main/java/com/java_school/final_task/configuration/ThymeleafConfig.java

@@ -5,8 +5,17 @@
 import org.thymeleaf.spring5.SpringTemplateEngine;
 import org.thymeleaf.templateresolver.ClassLoaderTemplateResolver;
 
+/**
+ * Configuration class for Thymeleaf template engine setup.
+ * Provides bean definitions for configuring Thymeleaf template resolution and processing.
+ */
 @Configuration
 public class ThymeleafConfig {
+    /**
+     * Configures and provides a ClassLoaderTemplateResolver bean for Thymeleaf.
+     *
+     * @return ClassLoaderTemplateResolver A configured template resolver for resolving templates from the classpath.
+     */
     @Bean
     public ClassLoaderTemplateResolver templateResolver() {
         ClassLoaderTemplateResolver templateResolver = new ClassLoaderTemplateResolver();
@@ -18,6 +27,11 @@ public ClassLoaderTemplateResolver templateResolver() {
         return templateResolver;
     }
 
+    /**
+     * Configures and provides a SpringTemplateEngine bean for Thymeleaf.
+     *
+     * @return SpringTemplateEngine A configured template engine that integrates with Spring and Thymeleaf.
+     */
     @Bean
     public SpringTemplateEngine templateEngine() {
         var templateEngine = new SpringTemplateEngine();

src/main/java/com/java_school/final_task/domain/order/impl/OrderServiceImpl.java

@@ -2,23 +2,18 @@
 
 import com.java_school.final_task.domain.book.BookEntity;
 import com.java_school.final_task.domain.book.BookRepository;
-import com.java_school.final_task.domain.order.OrderEntity;
-import com.java_school.final_task.domain.order.OrderRepository;
-import com.java_school.final_task.domain.order.OrderService;
-import com.java_school.final_task.domain.order.QOrderEntity;
+import com.java_school.final_task.domain.order.*;
 import com.java_school.final_task.domain.order.dto.OrderDTO;
 import com.java_school.final_task.domain.order.dto.OrderRequestDTO;
 import com.java_school.final_task.domain.order.dto.SaveOrderDTO;
 import com.java_school.final_task.domain.order_book.QOrderBookEntity;
 import com.java_school.final_task.domain.user.UserEntity;
 import com.java_school.final_task.domain.user.UserService;
-import com.java_school.final_task.domain.user.impl.UserServiceImpl;
 import com.java_school.final_task.exception.book.ProductNotAvailableException;
 import com.java_school.final_task.exception.book.ProductOutOfStockException;
 import com.java_school.final_task.exception.user.InactiveUserException;
 import com.java_school.final_task.utils.MailService;
 import com.java_school.final_task.utils.impl.AbstractServiceImpl;
-import com.java_school.final_task.utils.impl.MailServiceImpl;
 import com.querydsl.core.BooleanBuilder;
 import com.querydsl.core.types.dsl.StringExpression;
 import com.querydsl.jpa.impl.JPAQueryFactory;
@@ -34,35 +29,33 @@
 import java.time.LocalDate;
 
 /**
- * Service class responsible for the interaction between the {@link OrderRepository} and the {@link OrderRestControllerImpl}.
+ * Service class responsible for the interaction between the {@link OrderRepository} and the {@link OrderRestController}.
  * Obtains data from the {@link OrderRepository} and returns the object(s) of the {@link OrderEntity} as {@link OrderDTO}
- * to the {@link OrderRestControllerImpl}.
+ * to the {@link OrderRestController}.
  */
-@Secured({"ROLE_ADMIN", "EMPLOYEE", "CLIENT"})
+@Secured({"ROLE_ADMIN", "ROLE_EMPLOYEE", "ROLE_CLIENT"})
 @Service
 public class OrderServiceImpl
         extends AbstractServiceImpl<OrderRepository, OrderEntity, OrderDTO, Integer>
         implements OrderService {
     // Fields
     private final UserService userService;
-
-    private final MailServiceImpl mailService;
+    private final MailService mailService;
     private final BookRepository bookRepository;
-
     private final JPAQueryFactory queryFactory;
 
     /**
      * All arguments constructor.
      *
      * @param repository     {@link OrderRepository} of the {@link OrderEntity}.
      * @param modelMapper    ModelMapper that converts the {@link OrderEntity} instance to {@link OrderDTO}
-     * @param userService    {@link UserServiceImpl} of the {@link UserEntity}.
-     * @param mailService    {@link MailServiceImpl} of the {@link MailService}
+     * @param userService    {@link UserService} of the {@link UserEntity}.
+     * @param mailService    {@link MailService} of the {@link MailService}
      * @param bookRepository {@link BookRepository} of the {@link BookEntity}.
      * @param queryFactory   {@link JPAQueryFactory} for query and DML clause creation.
      */
-    public OrderServiceImpl(OrderRepository repository, ModelMapper modelMapper, MailServiceImpl mailService,
-                            UserServiceImpl userService, BookRepository bookRepository, JPAQueryFactory queryFactory) {
+    public OrderServiceImpl(OrderRepository repository, ModelMapper modelMapper, MailService mailService,
+                            UserService userService, BookRepository bookRepository, JPAQueryFactory queryFactory) {
         super(repository, modelMapper);
         this.userService = userService;
         this.mailService = mailService;
@@ -101,7 +94,7 @@ public BigDecimal calculateTotalRevenue(LocalDate startDate, LocalDate endDate)
     }
 
     @Override
-    @Secured({"ROLE_ADMIN", "EMPLOYEE"})
+    @Secured({"ROLE_ADMIN", "ROLE_EMPLOYEE"})
     public void deleteInstance(Integer integer) {
         super.deleteInstance(integer);
     }
@@ -117,11 +110,7 @@ public Page<OrderDTO> getAllInstances(OrderRequestDTO orderRequestDTO) {
 
         // Check if the current user is active
         if (currentUser.isActive()) {
-            // Check which parameters are present and build a query
-            handleParameter(orderRequestDTO.getDeliveryMethod(), queryBuilder, qOrder.deliveryMethod.name);
-            handleParameter(orderRequestDTO.getOrderStatus(), queryBuilder, qOrder.orderStatus.name);
-            handleParameter(orderRequestDTO.getPaymentMethod(), queryBuilder, qOrder.paymentMethod.name);
-            handleParameter(orderRequestDTO.getPaymentStatus(), queryBuilder, qOrder.paymentStatus.name);
+            handleQueryParameters(orderRequestDTO, queryBuilder, qOrder);
 
             if (orderRequestDTO.getDate() != null) {
                 queryBuilder.and(qOrder.date.eq(orderRequestDTO.getDate()));
@@ -201,7 +190,28 @@ public OrderDTO saveInstance(SaveOrderDTO saveOrderDTO) {
         return modelMapper.map(repository.save(newOrder), getDTOClass());
     }
 
-    private void handleParameter(String parameter, BooleanBuilder queryBuilder, StringExpression expression) {
-        queryBuilder.and(!"".equals(parameter) ? expression.containsIgnoreCase(parameter) : null);
+    /**
+     * Handles a query parameter by adding a condition to the BooleanBuilder.
+     *
+     * @param parameter    The query parameter to handle.
+     * @param queryBuilder The BooleanBuilder to which the condition will be added.
+     * @param expression   The StringExpression representing the field to filter on.
+     */
+    private void handleQueryParameter(String parameter, BooleanBuilder queryBuilder, StringExpression expression) {
+        queryBuilder.and(!parameter.trim().isEmpty() ? expression.containsIgnoreCase(parameter) : null);
+    }
+
+    /**
+     * Handles multiple query parameters for an order request by delegating to handleQueryParameter for each parameter.
+     *
+     * @param orderRequestDTO The OrderRequestDTO containing the query parameters.
+     * @param queryBuilder    The BooleanBuilder to which the conditions will be added.
+     * @param qOrder          The QOrderEntity representing the query entity.
+     */
+    private void handleQueryParameters(OrderRequestDTO orderRequestDTO, BooleanBuilder queryBuilder, QOrderEntity qOrder) {
+        handleQueryParameter(orderRequestDTO.getDeliveryMethod(), queryBuilder, qOrder.deliveryMethod.name);
+        handleQueryParameter(orderRequestDTO.getOrderStatus(), queryBuilder, qOrder.orderStatus.name);
+        handleQueryParameter(orderRequestDTO.getPaymentMethod(), queryBuilder, qOrder.paymentMethod.name);
+        handleQueryParameter(orderRequestDTO.getPaymentStatus(), queryBuilder, qOrder.paymentStatus.name);
     }
 }

src/main/java/com/java_school/final_task/domain/user/impl/UserServiceImpl.java

@@ -23,6 +23,8 @@
 
 import java.util.Optional;
 
+// TODO Too many comments
+
 /**
  * Service class responsible for the interaction between the {@link UserRepository} and the
  * {@link UserRestControllerImpl}. Obtains data from the

src/main/java/com/java_school/final_task/utils/MailService.java

@@ -2,7 +2,16 @@
 
 import com.java_school.final_task.domain.order.dto.SaveOrderDTO;
 
+/**
+ * Interface for sending emails related to orders.
+ * Defines methods for sending order confirmation emails.
+ */
 public interface MailService {
+    /**
+     * Sends an order confirmation email based on the provided SaveOrderDTO.
+     *
+     * @param saveOrderDTO The SaveOrderDTO object containing the details of the order.
+     */
     void sendOrderConfirmationMail(SaveOrderDTO saveOrderDTO);
 
     //void sendRegistrationConfirmationMail(String to, String text);

src/main/java/com/java_school/final_task/utils/PDFService.java

@@ -2,6 +2,16 @@
 
 import com.java_school.final_task.domain.order.dto.SaveOrderDTO;
 
+/**
+ * Interface for PDF generation service.
+ * Defines methods for generating PDF documents related to orders.
+ */
 public interface PDFService {
+    /**
+     * Generates a PDF document containing order details based on the provided SaveOrderDTO.
+     *
+     * @param saveOrderDTO The SaveOrderDTO object containing the details of the order.
+     * @return byte[] The byte array representing the generated PDF document.
+     */
     byte[] generateOrderDetailsPDF(SaveOrderDTO saveOrderDTO);
 }

src/main/java/com/java_school/final_task/utils/impl/MailServiceImpl.java

@@ -4,6 +4,7 @@
 import com.java_school.final_task.domain.order_book.OrderBookEntity;
 import com.java_school.final_task.exception.MessagingExceptionWrapper;
 import com.java_school.final_task.utils.MailService;
+import com.java_school.final_task.utils.PDFService;
 import jakarta.mail.MessagingException;
 import jakarta.mail.internet.MimeMessage;
 import org.springframework.beans.factory.annotation.Value;
@@ -18,57 +19,106 @@
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * {@link MailService} implementation responsible for sending emails.
+ * This class implements the MailService interface and provides functionality to generate HTML content,
+ * attach PDF documents, and send emails using Spring's JavaMailSender.
+ */
 @Service
 public class MailServiceImpl implements MailService {
     private final JavaMailSender mailSender;
-
     private final SpringTemplateEngine thymeleafTemplateEngine;
-
-    private final PDFServiceImpl pdfService;
-
-    @Value("${MAIL_USERNAME}")
-    private String mailFromAddress;
-
-    public MailServiceImpl(JavaMailSender mailSender, PDFServiceImpl pdfService, SpringTemplateEngine thymeleafTemplateEngine) {
+    private final PDFService pdfService;
+    private final String mailFromAddress;
+
+    /**
+     * Constructs a new MailServiceImpl with the specified dependencies.
+     *
+     * @param mailSender              The {@link JavaMailSender} instance used to send emails.
+     * @param pdfService              The {@link PDFServiceImpl} instance used to generate PDF documents.
+     * @param thymeleafTemplateEngine The {@link SpringTemplateEngine} instance used to process HTML templates.
+     * @param mailFromAddress         The email address from which the emails will be sent.
+     */
+    public MailServiceImpl(
+            JavaMailSender mailSender,
+            PDFService pdfService,
+            SpringTemplateEngine thymeleafTemplateEngine,
+            @Value("${MAIL_USERNAME}") String mailFromAddress
+    ) {
         this.mailSender = mailSender;
         this.thymeleafTemplateEngine = thymeleafTemplateEngine;
         this.pdfService = pdfService;
+        this.mailFromAddress = mailFromAddress;
     }
 
+    /**
+     * Sends an order confirmation email to the user with the order details.
+     *
+     * @param saveOrderDTO The {@link SaveOrderDTO} instance containing the order details.
+     */
     @Override
     public void sendOrderConfirmationMail(SaveOrderDTO saveOrderDTO) {
-        try {
-            byte[] pdfContent = pdfService.generateOrderDetailsPDF(saveOrderDTO);
+        byte[] pdfContent = pdfService.generateOrderDetailsPDF(saveOrderDTO);
 
-            // Prepare the model for the template
-            Map<String, Object> templateModel = new HashMap<>();
-            templateModel.put("customerName", saveOrderDTO.getOrder().getUser().getName());
-            templateModel.put("orderedBooks", saveOrderDTO.getOrderedBooks());
-            BigDecimal total = saveOrderDTO.getOrderedBooks().stream().map(OrderBookEntity::getTotal).reduce(BigDecimal.ZERO, BigDecimal::add);
-            templateModel.put("total", total);
+        String htmlContent = this.generateHTMLContent(saveOrderDTO);
 
-            // Process the template
-            Context thymeleafContext = new Context();
-            thymeleafContext.setVariables(templateModel);
-            String htmlContent = thymeleafTemplateEngine.process("order-confirmation-mail", thymeleafContext);
+        MimeMessage message = createMimeMessage(saveOrderDTO, htmlContent, pdfContent);
 
-            MimeMessage message = mailSender.createMimeMessage();
+        mailSender.send(message);
+    }
+
+    /**
+     * Generates HTML content for the order confirmation email.
+     *
+     * @param saveOrderDTO The {@code SaveOrderDTO} containing the order details.
+     * @return The HTML content of the email.
+     */
+    private String generateHTMLContent(SaveOrderDTO saveOrderDTO) {
+        Map<String, Object> templateModel = this.generateTemplateModel(saveOrderDTO);
+        Context thymeleafContext = new Context();
+        thymeleafContext.setVariables(templateModel);
+        return thymeleafTemplateEngine.process("order-confirmation-mail", thymeleafContext);
+    }
+
+    /**
+     * Generates a template model for the order confirmation email.
+     *
+     * @param saveOrderDTO The {@code SaveOrderDTO} instance containing the order details.
+     * @return The template model containing data for the email template.
+     */
+    private Map<String, Object> generateTemplateModel(SaveOrderDTO saveOrderDTO) {
+        Map<String, Object> templateModel = new HashMap<>();
+        templateModel.put("customerName", saveOrderDTO.getOrder().getUser().getName());
+        templateModel.put("orderedBooks", saveOrderDTO.getOrderedBooks());
+        BigDecimal total = saveOrderDTO.getOrderedBooks().stream().map(OrderBookEntity::getTotal).reduce(BigDecimal.ZERO, BigDecimal::add);
+        templateModel.put("total", total);
+        return templateModel;
+    }
+
+    /**
+     * Creates a MimeMessage for the order confirmation email.
+     *
+     * @param saveOrderDTO The {@code SaveOrderDTO} instance containing the order details.
+     * @param htmlContent  The HTML content of the email.
+     * @param pdfContent   The content of the PDF attachment.
+     * @return The MimeMessage for the email.
+     */
+    private MimeMessage createMimeMessage(SaveOrderDTO saveOrderDTO, String htmlContent, byte[] pdfContent) {
+        MimeMessage message = mailSender.createMimeMessage();
+        try {
             MimeMessageHelper helper = new MimeMessageHelper(message, true);
             helper.setTo(saveOrderDTO.getOrder().getUser().getEmail());
             helper.setSubject("Order confirmation at Online Bookstore");
-
-            // Set the content of the email
             helper.setText(htmlContent, true);
 
-            // Add the PDF as an attachment
             String attachmentName = "order_" + saveOrderDTO.getOrder().getDate() + ".pdf";
             helper.addAttachment(attachmentName, new ByteArrayResource(pdfContent));
-
-            this.sendMail(message);
+            message.setFrom(mailFromAddress);
         } catch (MessagingException e) {
             throw new MessagingExceptionWrapper();
         }
 
+        return message;
     }
 
     /*@Override
@@ -81,14 +131,4 @@ public void sendRegistrationConfirmationMail(String to, String text) {
 
         this.sendMail(message);
     }*/
-
-    private void sendMail(MimeMessage message) {
-        try {
-            message.setFrom(mailFromAddress);
-        } catch (MessagingException e) {
-            throw new MessagingExceptionWrapper();
-        }
-
-        mailSender.send(message);
-    }
 }