Added logging. Small refactoring.

pom.xml

@@ -26,11 +26,12 @@
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-thymeleaf</artifactId>
-		</dependency>
+			<exclusions>
-		<dependency>
+				<exclusion>
-			<groupId>nz.net.ultraq.thymeleaf</groupId>
+					<groupId>org.springframework.boot</groupId>
-			<artifactId>thymeleaf-layout-dialect</artifactId>
+					<artifactId>spring-boot-starter-logging</artifactId>
-			<version>2.3.0</version>
+				</exclusion>
+			</exclusions>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
@@ -42,23 +43,30 @@
 			<artifactId>spring-boot-devtools</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>nz.net.ultraq.thymeleaf</groupId>
+			<artifactId>thymeleaf-layout-dialect</artifactId>
+			<version>2.3.0</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-log4j2</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.liquibase</groupId>
 			<artifactId>liquibase-core</artifactId>
 		</dependency>
-
 		<dependency>
 			<groupId>mysql</groupId>
 			<artifactId>mysql-connector-java</artifactId>
 			<version>8.0.16</version>
 			<scope>runtime</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.springframework.boot</groupId>
-			<artifactId>spring-boot-starter-test</artifactId>
-			<scope>test</scope>
-		</dependency>
-
 		<dependency>
 			<groupId>com.github.javafaker</groupId>
 			<artifactId>javafaker</artifactId>

src/main/java/com/github/prominence/carrepair/controller/ClientController.java

@@ -2,6 +2,8 @@ package com.github.prominence.carrepair.controller;
 
 import com.github.prominence.carrepair.model.Client;
 import com.github.prominence.carrepair.service.ClientService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.web.PageableDefault;
@@ -19,6 +21,8 @@ import java.util.Optional;
 @RequestMapping("/client")
 public class ClientController {
 
+    private static final Logger logger = LogManager.getLogger(ClientController.class);
+
     private ClientService clientService;
 
     public ClientController(ClientService clientService) {
@@ -28,6 +32,7 @@ public class ClientController {
     @GetMapping
     public String index(@PageableDefault Pageable pageable, ModelMap modelMap) {
         Page<Client> clientList = clientService.findAll(pageable);
+        logger.trace("Request to open list page for Clients. Returning {} page.", () -> pageable.getPageNumber() + 1);
 
         modelMap.addAttribute("clientList", clientList.getContent());
         modelMap.addAttribute("totalPages", clientList.getTotalPages());
@@ -37,6 +42,7 @@ public class ClientController {
 
     @GetMapping(value = "/create")
     public String create(Model model) {
+        logger.trace("Request to open create page for Client.");
         model.addAttribute("client", new Client());
 
         return "client/edit";
@@ -44,19 +50,21 @@ public class ClientController {
 
     @GetMapping(value = "/edit/{id}")
     public String edit(@PathVariable Long id, Model model) {
+        logger.trace("Request to open edit page for Client[{}].", () -> id);
         Optional<Client> clientOptional = clientService.findById(id);
         if (clientOptional.isPresent()) {
             model.addAttribute("client", clientOptional.get());
             return "client/edit";
         } else {
-            // TODO: need to show warning
             return "redirect:/client";
         }
     }
 
     @PostMapping(value = "/update/{id}")
     public String update(@Valid Client client, BindingResult bindingResult, @PathVariable long id) {
+        logger.trace("Request to save {}.", () -> client);
         if (bindingResult.hasErrors()) {
+            logger.trace("{} has validation {} errors and won't be saved.", () -> client, bindingResult::getErrorCount);
             client.setId(id); // why should we do this?
             return "client/edit";
         }
@@ -67,7 +75,9 @@ public class ClientController {
 
     @PostMapping(value = "/create")
     public String save(@Valid Client client, BindingResult bindingResult) {
+        logger.trace("Request to create {}.", () -> client);
         if (bindingResult.hasErrors()) {
+            logger.trace("{} has validation {} errors and won't be created.", () -> client, bindingResult::getErrorCount);
             return "client/edit";
         }
 
@@ -77,8 +87,8 @@ public class ClientController {
 
     @DeleteMapping(value = "/delete/{id}")
     public ResponseEntity delete(@PathVariable Long id) {
+        logger.trace("Request to delete Client[{}].", () -> id);
         boolean deleteSuccess = clientService.deleteClientById(id);
-
         if (deleteSuccess) {
             return ResponseEntity.ok().build();
         } else {

src/main/java/com/github/prominence/carrepair/controller/HomeController.java

@@ -1,14 +1,18 @@
 package com.github.prominence.carrepair.controller;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 
 @Controller
 @RequestMapping("/")
 public class HomeController {
+    private static final Logger logger = LogManager.getLogger(HomeController.class);
 
     @RequestMapping
     public String index() {
-        return "home";
+        logger.trace("Request to open home page.");
+        return "index";
     }
 }

src/main/java/com/github/prominence/carrepair/controller/MechanicController.java

@@ -3,6 +3,8 @@ package com.github.prominence.carrepair.controller;
 import com.github.prominence.carrepair.enums.OrderStatus;
 import com.github.prominence.carrepair.model.Mechanic;
 import com.github.prominence.carrepair.service.MechanicService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.web.PageableDefault;
@@ -20,6 +22,7 @@ import java.util.Optional;
 @Controller
 @RequestMapping("/mechanic")
 public class MechanicController {
+    private static final Logger logger = LogManager.getLogger(MechanicController.class);
 
     private MechanicService mechanicService;
 
@@ -29,16 +32,18 @@ public class MechanicController {
 
     @GetMapping
     public String index(@PageableDefault Pageable pageable, ModelMap modelMap) {
-        Page<Mechanic> clientList = mechanicService.findAll(pageable);
+        Page<Mechanic> mechanicList = mechanicService.findAll(pageable);
+        logger.trace("Request to open list page for Mechanics. Returning {} page.", () -> pageable.getPageNumber() + 1);
 
-        modelMap.addAttribute("mechanicList", clientList.getContent());
+        modelMap.addAttribute("mechanicList", mechanicList.getContent());
-        modelMap.addAttribute("totalPages", clientList.getTotalPages());
+        modelMap.addAttribute("totalPages", mechanicList.getTotalPages());
 
         return "mechanic/index";
     }
 
     @GetMapping(value = "/create")
     public String create(Model model) {
+        logger.trace("Request to open create page for Mechanic.");
         model.addAttribute("mechanic", new Mechanic());
 
         return "mechanic/edit";
@@ -46,41 +51,45 @@ public class MechanicController {
 
     @GetMapping(value = "/edit/{id}")
     public String edit(@PathVariable Long id, Model model) {
-        Optional<Mechanic> clientOptional = mechanicService.findById(id);
+        logger.trace("Request to open edit page for Mechanic[{}].", () -> id);
-        if (clientOptional.isPresent()) {
+        Optional<Mechanic> mechanicOptional = mechanicService.findById(id);
-            model.addAttribute("mechanic", clientOptional.get());
+        if (mechanicOptional.isPresent()) {
+            model.addAttribute("mechanic", mechanicOptional.get());
             return "mechanic/edit";
         } else {
-            // TODO: need to show warning
             return "redirect:/mechanic";
         }
     }
 
     @PostMapping(value = "/update/{id}")
-    public String update(@Valid Mechanic client, BindingResult bindingResult, @PathVariable long id) {
+    public String update(@Valid Mechanic mechanic, BindingResult bindingResult, @PathVariable long id) {
+        logger.trace("Request to save {}.", () -> mechanic);
         if (bindingResult.hasErrors()) {
-            client.setId(id); // why should we do this?
+            logger.trace("{} has validation {} errors and won't be saved.", () -> mechanic, bindingResult::getErrorCount);
+            mechanic.setId(id); // why should we do this?
             return "mechanic/edit";
         }
 
-        mechanicService.save(client);
+        mechanicService.save(mechanic);
         return "redirect:/mechanic";
     }
 
     @PostMapping(value = "/create")
-    public String save(@Valid Mechanic client, BindingResult bindingResult) {
+    public String save(@Valid Mechanic mechanic, BindingResult bindingResult) {
+        logger.trace("Request to create {}.", () -> mechanic);
         if (bindingResult.hasErrors()) {
+            logger.trace("{} has validation {} errors and won't be created.", () -> mechanic, bindingResult::getErrorCount);
             return "mechanic/edit";
         }
 
-        mechanicService.save(client);
+        mechanicService.save(mechanic);
         return "redirect:/mechanic";
     }
 
     @DeleteMapping(value = "/delete/{id}")
     public ResponseEntity delete(@PathVariable Long id) {
+        logger.trace("Request to delete Mechanic[{}].", () -> id);
         boolean deleteSuccess = mechanicService.deleteMechanicById(id);
-
         if (deleteSuccess) {
             return ResponseEntity.ok().build();
         } else {
@@ -90,6 +99,7 @@ public class MechanicController {
 
     @GetMapping(value = "/statistics/{id}")
     public String statistics(@PathVariable Long id, Model model) {
+        logger.trace("Request to open statistics for Mechanic[{}].", () -> id);
         Map<OrderStatus, Integer> mechanicStatistics = mechanicService.getOrderStatistics(id);
         model.addAttribute("statistics", mechanicStatistics);
 

src/main/java/com/github/prominence/carrepair/controller/OrderController.java

@@ -4,6 +4,8 @@ import com.github.prominence.carrepair.enums.OrderStatus;
 import com.github.prominence.carrepair.model.Order;
 import com.github.prominence.carrepair.repository.spec.OrderSpecifications;
 import com.github.prominence.carrepair.service.OrderService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.web.PageableDefault;
@@ -19,6 +21,7 @@ import java.util.Optional;
 @Controller
 @RequestMapping(value = "/order")
 public class OrderController {
+    private static final Logger logger = LogManager.getLogger(OrderController.class);
 
     private OrderService orderService;
 
@@ -30,6 +33,7 @@ public class OrderController {
     public String index(@PageableDefault Pageable pageable, @RequestParam(required = false) String client, @RequestParam(required = false) String description,
                         @RequestParam(required = false) OrderStatus orderStatus, ModelMap modelMap) {
         Page<Order> orderList = orderService.findAll(OrderSpecifications.search(client, description, orderStatus), pageable);
+        logger.trace("Request to open list page for Orders. Returning {} page.", () -> pageable.getPageNumber() + 1);
 
         modelMap.addAttribute("orderList", orderList.getContent());
         modelMap.addAttribute("totalPages", orderList.getTotalPages());
@@ -40,6 +44,7 @@ public class OrderController {
 
     @GetMapping(value = "/create")
     public String create(Model model) {
+        logger.trace("Request to open create page for Order.");
         model.addAttribute("order", new Order());
         model.addAttribute("orderStatuses", OrderStatus.values());
 
@@ -48,21 +53,23 @@ public class OrderController {
 
     @GetMapping(value = "/edit/{id}")
     public String edit(@PathVariable Long id, Model model) {
+        logger.trace("Request to open edit page for Order[{}].", () -> id);
         Optional<Order> orderOptional = orderService.findById(id);
         if (orderOptional.isPresent()) {
             model.addAttribute("order", orderOptional.get());
             model.addAttribute("orderStatuses", OrderStatus.values());
             return "order/edit";
         } else {
-            // TODO: need to show warning
             return "redirect:/order";
         }
     }
 
     @PostMapping(value = "/update/{id}")
     public String update(Order order, BindingResult bindingResult, @PathVariable long id, Long clientId, Long mechanicId, Model model) {
+        logger.trace("Request to save {}.", () -> order);
         orderService.fetchNestedObjectsAndValidate(order, clientId, mechanicId, bindingResult);
         if (bindingResult.hasErrors()) {
+            logger.trace("{} has validation {} errors and won't be saved.", () -> order, bindingResult::getErrorCount);
             order.setId(id); // why should we do this?
             model.addAttribute("orderStatuses", OrderStatus.values());
             return "order/edit";
@@ -74,8 +81,10 @@ public class OrderController {
 
     @PostMapping(value = "/create")
     public String save(Order order, BindingResult bindingResult, Long clientId, Long mechanicId, Model model) {
+        logger.trace("Request to create {}.", () -> order);
         orderService.fetchNestedObjectsAndValidate(order, clientId, mechanicId, bindingResult);
         if (bindingResult.hasErrors()) {
+            logger.trace("{} has validation {} errors and won't be created.", () -> order, bindingResult::getErrorCount);
             model.addAttribute("orderStatuses", OrderStatus.values());
             return "order/edit";
         }
@@ -86,8 +95,8 @@ public class OrderController {
 
     @DeleteMapping(value = "/delete/{id}")
     public ResponseEntity delete(@PathVariable Long id) {
+        logger.trace("Request to delete Order[{}].", () -> id);
         boolean deleteSuccess = orderService.deleteOrderById(id);
-
         if (deleteSuccess) {
             return ResponseEntity.ok().build();
         } else {

src/main/java/com/github/prominence/carrepair/demo/DemoDataPopulator.java

@@ -9,6 +9,8 @@ import com.github.prominence.carrepair.service.ClientService;
 import com.github.prominence.carrepair.service.MechanicService;
 import com.github.prominence.carrepair.service.OrderService;
 import org.apache.commons.lang3.RandomUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.data.domain.PageRequest;
@@ -26,8 +28,10 @@ import java.util.stream.Stream;
 @Component
 public class DemoDataPopulator {
     private static final int COUNT = 100;
+    private static final int DEFAULT_PAGE_SIZE = 10;
+    private final Logger logger = LogManager.getLogger(DemoDataPopulator.class);
 
-    private Faker faker = new Faker();
+    private final Faker faker = new Faker();
 
     @Bean
     public CommandLineRunner clientDemoData(ClientService clientService) {
@@ -37,9 +41,9 @@ public class DemoDataPopulator {
             client.setLastName(faker.name().lastName());
             client.setMiddleName(faker.name().username());
             client.setPhoneNo(faker.phoneNumber().phoneNumber());
-            System.out.println(client); // demo output
             return client;
         }).limit(COUNT).collect(Collectors.toList());
+        logger.info("[Demo Data] Populated {} clients.", demoClientList::size);
 
         return args -> demoClientList.forEach(clientService::save);
     }
@@ -52,9 +56,9 @@ public class DemoDataPopulator {
             mechanic.setLastName(faker.name().lastName());
             mechanic.setMiddleName(faker.name().username());
             mechanic.setHourlyPayment(BigDecimal.valueOf(faker.number().randomDouble(3, 100, 999)));
-            System.out.println(mechanic); // demo output
             return mechanic;
         }).limit(COUNT).collect(Collectors.toList());
+        logger.info("[Demo Data] Populated {} mechanics.", demoMechanicList::size);
 
         return args -> demoMechanicList.forEach(mechanicService::save);
     }
@@ -80,22 +84,22 @@ public class DemoDataPopulator {
             final Client randomClient = clientListSlice.get(RandomUtils.nextInt(0, clientListSlice.size()));
             order.setClient(randomClient);
 
-            final List<Mechanic> mechanicListSlise = mechanicService.findAll(getRandomPageable(mechanicsCount)).getContent();
+            final List<Mechanic> mechanicListSlice = mechanicService.findAll(getRandomPageable(mechanicsCount)).getContent();
-            final Mechanic randomMechanic = mechanicListSlise.get(RandomUtils.nextInt(0, mechanicListSlise.size()));
+            final Mechanic randomMechanic = mechanicListSlice.get(RandomUtils.nextInt(0, mechanicListSlice.size()));
             order.setMechanic(randomMechanic);
 
-            System.out.println(order); // demo output
             return order;
         }).limit(COUNT).collect(Collectors.toList());
+        logger.info("[Demo Data] Populated {} orders.", demoOrderList::size);
 
         return args -> demoOrderList.forEach(orderService::save);
     }
 
     private Pageable getRandomPageable(long totalRecords) {
-        final int size = 10;
+        final int totalPages = (int) (totalRecords / DEFAULT_PAGE_SIZE);
-        final int totalPages = (int) (totalRecords / size);
+        final PageRequest pageRequest = PageRequest.of(RandomUtils.nextInt(0, totalPages), DEFAULT_PAGE_SIZE);
-
+        logger.trace("[Demo Data] Random page: {}", () -> pageRequest);
-        return PageRequest.of(RandomUtils.nextInt(0, totalPages), size);
+        return pageRequest;
     }
 
 }

src/main/java/com/github/prominence/carrepair/formatter/CustomDateTimeFormatter.java

@@ -1,5 +1,7 @@
 package com.github.prominence.carrepair.formatter;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.format.Formatter;
 import org.springframework.stereotype.Component;
 
@@ -10,13 +12,19 @@ import java.util.Locale;
 
 @Component
 public class CustomDateTimeFormatter implements Formatter<LocalDateTime> {
+    private static final Logger logger = LogManager.getLogger(CustomDateTimeFormatter.class);
+
     @Override
     public LocalDateTime parse(String text, Locale locale) throws ParseException {
-        return LocalDateTime.parse(text, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+        final LocalDateTime parsedDateTime = LocalDateTime.parse(text, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+        logger.trace("Parsing String[{}] to LocalDateTime instance: {}.", () -> text, () -> parsedDateTime);
+        return parsedDateTime;
     }
 
     @Override
     public String print(LocalDateTime object, Locale locale) {
-        return object.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+        final String formattedString = object.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+        logger.trace("Formatting LocalDateTime[{}] to String instance: {}.", () -> object, () -> formattedString);
+        return formattedString;
     }
 }

src/main/java/com/github/prominence/carrepair/formatter/OrderStatusFormatter.java

@@ -2,6 +2,8 @@ package com.github.prominence.carrepair.formatter;
 
 import com.github.prominence.carrepair.enums.OrderStatus;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.format.Formatter;
 import org.springframework.stereotype.Component;
 
@@ -10,13 +12,19 @@ import java.util.Locale;
 
 @Component
 public class OrderStatusFormatter implements Formatter<OrderStatus> {
+    private static final Logger logger = LogManager.getLogger(OrderStatusFormatter.class);
+
     @Override
     public OrderStatus parse(String text, Locale locale) throws ParseException {
-        return OrderStatus.valueOf(text.toUpperCase());
+        final OrderStatus parsedOrderStatus = OrderStatus.valueOf(text.toUpperCase());
+        logger.trace("Parsing String[{}] to OrderStatus instance: {}.", () -> text, () -> parsedOrderStatus);
+        return parsedOrderStatus;
     }
 
     @Override
     public String print(OrderStatus object, Locale locale) {
-        return StringUtils.capitalize(object.toString().toLowerCase());
+        final String formattedOrderStatus = StringUtils.capitalize(object.toString().toLowerCase());
+        logger.trace("Formatting OrderStatus[{}] to String instance: {}.", () -> object, () -> formattedOrderStatus);
+        return formattedOrderStatus;
     }
 }

src/main/java/com/github/prominence/carrepair/repository/spec/OrderSpecifications.java

@@ -4,6 +4,8 @@ import com.github.prominence.carrepair.enums.OrderStatus;
 import com.github.prominence.carrepair.model.Client;
 import com.github.prominence.carrepair.model.Order;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.jpa.domain.Specification;
 import org.springframework.lang.Nullable;
 
@@ -13,8 +15,11 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class OrderSpecifications {
+    private static final Logger logger = LogManager.getLogger(OrderSpecifications.class);
 
     public static Specification<Order> search(@Nullable String clientQuery, @Nullable String orderDescriptionQuery, @Nullable OrderStatus orderStatusQuery) {
+        logger.debug("Creating specification for order search. Params: clientQuery=[{}], orderDescriptionQuery=[{}], orderStatusQuery=[{}]",
+                () -> clientQuery, () -> orderDescriptionQuery, () -> orderStatusQuery);
         return (root, criteriaQuery, criteriaBuilder) -> {
             List<Predicate> predicates = new ArrayList<>();
             if (!StringUtils.isEmpty(clientQuery)) {

src/main/java/com/github/prominence/carrepair/service/ClientService.java

@@ -2,6 +2,8 @@ package com.github.prominence.carrepair.service;
 
 import com.github.prominence.carrepair.model.Client;
 import com.github.prominence.carrepair.repository.ClientRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -11,6 +13,7 @@ import java.util.Optional;
 
 @Service
 public class ClientService {
+    private static final Logger logger = LogManager.getLogger(ClientService.class);
 
     private ClientRepository clientRepository;
 
@@ -19,31 +22,43 @@ public class ClientService {
     }
 
     public Page<Client> findAll(Pageable pageable) {
-        return clientRepository.findAll(pageable);
+        final Page<Client> clientPage = clientRepository.findAll(pageable);
+        logger.trace(clientPage);
+        return clientPage;
     }
 
     public Optional<Client> findById(Long id) {
-        return clientRepository.findById(id);
+        final Optional<Client> clientOptional = clientRepository.findById(id);
+        logger.debug("{} found by id={}", () -> clientOptional, () -> id);
+        return clientOptional;
     }
 
     public Client save(Client client) {
-        return clientRepository.save(client);
+        final Client clientToSave = clientRepository.save(client);
+        logger.trace("[{}] was saved.", () -> clientToSave);
+        return clientToSave;
     }
 
     public boolean deleteClientById(Long id) {
         try {
             clientRepository.deleteById(id);
+            logger.debug("Client[id={}] was deleted.", () -> id);
             return true;
         } catch (Exception e) {
+            logger.error("Client[id={}] wasn't deleted. Exception: {}", () -> id, e::getMessage);
             return false;
         }
     }
 
     public long getClientCount() {
-        return clientRepository.count();
+        final long clientCount = clientRepository.count();
+        logger.trace("Found {} clients.", () -> clientCount);
+        return clientCount;
     }
 
     public List<Client> searchByInitials(String query) {
-        return clientRepository.findAllByInitials(query);
+        final List<Client> allByInitials = clientRepository.findAllByInitials(query);
+        logger.debug("Found {} clients by initials: {}.", allByInitials::size, () -> query);
+        return allByInitials;
     }
 }

src/main/java/com/github/prominence/carrepair/service/MechanicService.java

@@ -5,6 +5,8 @@ import com.github.prominence.carrepair.model.Mechanic;
 import com.github.prominence.carrepair.model.Order;
 import com.github.prominence.carrepair.repository.MechanicRepository;
 import com.github.prominence.carrepair.repository.OrderRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -16,6 +18,7 @@ import java.util.Optional;
 
 @Service
 public class MechanicService {
+    private static final Logger logger = LogManager.getLogger(MechanicService.class);
 
     private MechanicRepository mechanicRepository;
     private OrderRepository orderRepository;
@@ -26,22 +29,30 @@ public class MechanicService {
     }
 
     public Page<Mechanic> findAll(Pageable pageable) {
-        return mechanicRepository.findAll(pageable);
+        final Page<Mechanic> mechanicPage = mechanicRepository.findAll(pageable);
+        logger.trace(mechanicPage);
+        return mechanicPage;
     }
 
     public Optional<Mechanic> findById(Long id) {
-        return mechanicRepository.findById(id);
+        final Optional<Mechanic> mechanicOptional = mechanicRepository.findById(id);
+        logger.debug("{} found by id={}", () -> mechanicOptional, () -> id);
+        return mechanicOptional;
     }
 
     public Mechanic save(Mechanic client) {
-        return mechanicRepository.save(client);
+        final Mechanic mechanicToSave = mechanicRepository.save(client);
+        logger.trace("[{}] was saved.", () -> mechanicToSave);
+        return mechanicToSave;
     }
 
     public boolean deleteMechanicById(Long id) {
         try {
             mechanicRepository.deleteById(id);
+            logger.debug("Mechanic[id={}] was deleted.", () -> id);
             return true;
         } catch (Exception e) {
+            logger.error("Mechanic[id={}] wasn't deleted. Exception: {}", () -> id, e::getMessage);
             return false;
         }
     }
@@ -55,15 +66,20 @@ public class MechanicService {
         List<Order> mechanicOrders = orderRepository.findAllByMechanic_Id(mechanicId);
 
         mechanicOrders.forEach(order -> statistics.merge(order.getOrderStatus(), 1, Integer::sum));
+        logger.trace("Mechanic statistics by ID={}: {}", () -> mechanicId, () -> statistics);
 
         return statistics;
     }
 
     public long getMechanicCount() {
-        return mechanicRepository.count();
+        final long mechanicCount = mechanicRepository.count();
+        logger.trace("Found {} mechanics.", () -> mechanicCount);
+        return mechanicCount;
     }
 
     public List<Mechanic> searchByInitials(String query) {
-        return mechanicRepository.findAllByInitials(query);
+        final List<Mechanic> allByInitials = mechanicRepository.findAllByInitials(query);
+        logger.debug("Found {} mechanics by initials: {}.", allByInitials::size, () -> query);
+        return allByInitials;
     }
 }

src/main/java/com/github/prominence/carrepair/service/OrderService.java

@@ -3,6 +3,8 @@ package com.github.prominence.carrepair.service;
 import com.github.prominence.carrepair.model.Order;
 import com.github.prominence.carrepair.repository.OrderRepository;
 import com.github.prominence.carrepair.validation.OrderValidator;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.domain.Specification;
@@ -14,6 +16,7 @@ import java.util.Optional;
 
 @Service
 public class OrderService {
+    private static final Logger logger = LogManager.getLogger(OrderService.class);
 
     private OrderRepository orderRepository;
 
@@ -31,35 +34,47 @@ public class OrderService {
     }
 
     public Page<Order> findAll(Specification<Order> specification, Pageable pageable) {
-        return orderRepository.findAll(specification, pageable);
+        final Page<Order> orderPage = orderRepository.findAll(specification, pageable);
+        logger.trace(orderPage);
+        return orderPage;
     }
 
     public Optional<Order> findById(Long id) {
-        return orderRepository.findById(id);
+        final Optional<Order> orderOptional = orderRepository.findById(id);
+        logger.debug("{} found by id={}", () -> orderOptional, () -> id);
+        return orderOptional;
     }
 
-    public Order save(Order client) {
+    public Order save(Order order) {
-        return orderRepository.save(client);
+        final Order orderToSave = orderRepository.save(order);
+        logger.trace("[{}] was saved.", () -> orderToSave);
+        return orderToSave;
     }
 
     public boolean deleteOrderById(Long id) {
         try {
             orderRepository.deleteById(id);
+            logger.debug("Order[id={}] was deleted.", () -> id);
             return true;
         } catch (Exception e) {
+            logger.error("Order[id={}] wasn't deleted. Exception: {}", () -> id, e::getMessage);
             return false;
         }
     }
 
     public long getOrderCount() {
-        return orderRepository.count();
+        final long orderCount = orderRepository.count();
+        logger.trace("Found {} orders.", () -> orderCount);
+        return orderCount;
     }
 
     public void fetchNestedObjectsAndValidate(Order order, Long clientId, Long mechanicId, BindingResult bindingResult) {
         if (clientId != null) {
+            logger.trace("Fetching Client[{}] for {}.", () -> clientId, () -> order);
             clientService.findById(clientId).ifPresent(order::setClient);
         }
         if (mechanicId != null) {
+            logger.trace("Fetching Mechanic[{}] for {}.", () -> clientId, () -> order);
             mechanicService.findById(mechanicId).ifPresent(order::setMechanic);
         }
         smartValidator.validate(order, bindingResult);

src/main/java/com/github/prominence/carrepair/validation/OrderValidator.java

@@ -2,6 +2,8 @@ package com.github.prominence.carrepair.validation;
 
 import com.github.prominence.carrepair.enums.OrderStatus;
 import com.github.prominence.carrepair.model.Order;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.springframework.stereotype.Component;
 import org.springframework.validation.Errors;
 import org.springframework.validation.Validator;
@@ -10,6 +12,8 @@ import java.time.LocalDateTime;
 
 @Component
 public class OrderValidator implements Validator {
+    private static final Logger logger = LogManager.getLogger(OrderValidator.class);
+
     @Override
     public boolean supports(Class<?> aClass) {
         return Order.class.isAssignableFrom(aClass);
@@ -20,12 +24,16 @@ public class OrderValidator implements Validator {
         Order order = (Order) o;
         LocalDateTime finishedOn = order.getFinishedOn();
         if (finishedOn != null) {
-            LocalDateTime startedOn = order.getCreatedOn();
+            LocalDateTime createdOn = order.getCreatedOn();
-            if (startedOn != null && order.getFinishedOn().isBefore(order.getCreatedOn())) {
+            if (createdOn != null && order.getFinishedOn().isBefore(order.getCreatedOn())) {
+                logger.debug("[{}] validation error: \"finishedOn\" value[{}] is before \"createdOn\"[{}].",
+                        () -> order, () -> finishedOn, () -> createdOn);
                 errors.rejectValue("finishedOn", "error.finishedOn.finishedBeforeStarted");
             }
 
             if (order.getOrderStatus() != OrderStatus.ACCEPTED) {
+                logger.debug("[{}] validation error: \"finishedOn\" cannot be set for order in status differ from {}.",
+                        () -> order, () -> OrderStatus.ACCEPTED);
                 errors.rejectValue("finishedOn", "error.finishedOn.incompatibleStatus");
             }
         }

src/main/resources/application.properties

@@ -11,7 +11,7 @@ spring.datasource.password=carrepair
 # JPA / HIBERNATE
 # ===============================
 
-spring.jpa.show-sql=true
+spring.jpa.show-sql=false
 spring.jpa.hibernate.ddl-auto=validate
 spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
 spring.jpa.database-platform=org.hibernate.dialect.MySQL5Dialect

src/main/resources/log4j2.properties

@@ -0,0 +1,23 @@
+name = LoggingsConfig
+property.filename = logs
+appenders = console, file
+
+appender.console.type = Console
+appender.console.name = STDOUT
+appender.console.layout.type = PatternLayout
+appender.console.layout.pattern = [%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n
+
+appender.file.type = File
+appender.file.name = LOGFILE
+appender.file.fileName=${filename}/application.log
+appender.file.layout.type=PatternLayout
+appender.file.layout.pattern=[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n
+
+loggers = base
+
+logger.base.name = com.github.prominence
+logger.base.level = DEBUG
+
+rootLogger.level = info
+rootLogger.appenderRefs = stdout
+rootLogger.appenderRef.stdout.ref = STDOUT