update according to comments

pom.xml

@@ -20,6 +20,8 @@
 			https://raw.githubusercontent.com/mate-academy/style-guides/master/java/checkstyle.xml
 		</maven.checkstyle.plugin.configLocation>
 		<springdoc.version>2.5.0</springdoc.version>
+		<mapstruct.version>1.5.5.Final</mapstruct.version>
+		<lombok.mapstruct.binding.version>0.2.0</lombok.mapstruct.binding.version>
 	</properties>
 	<dependencies>
 		<dependency>
@@ -85,6 +87,12 @@
 			<version>${springdoc.version}</version>
 		</dependency>
 
+		<dependency>
+			<groupId>org.mapstruct</groupId>
+			<artifactId>mapstruct</artifactId>
+			<version>${mapstruct.version}</version>
+		</dependency>
+
 	</dependencies>
 
 	<build>
@@ -112,6 +120,52 @@
 					<linkXRef>false</linkXRef>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<configuration>
+					<source>${java.version}</source>
+					<target>${java.version}</target>
+					<annotationProcessorPaths>
+						<path>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok</artifactId>
+							<version>${lombok.version}</version>
+						</path>
+						<path>
+							<groupId>org.mapstruct</groupId>
+							<artifactId>mapstruct-processor</artifactId>
+							<version>1.5.5.Final</version>
+						</path>
+						<path>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok-mapstruct-binding</artifactId>
+							<version>${lombok.mapstruct.binding.version}</version>
+						</path>
+					</annotationProcessorPaths>
+				</configuration>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-checkstyle-plugin</artifactId>
+				<version>3.3.0</version>
+				<executions>
+					<execution>
+						<phase>compile</phase>
+						<goals>
+							<goal>check</goal>
+						</goals>
+					</execution>
+				</executions>
+				<configuration>
+					<configLocation>${maven.checkstyle.plugin.configLocation}</configLocation>
+					<encoding>UTF-8</encoding>
+					<consoleOutput>true</consoleOutput>
+					<failsOnError>true</failsOnError>
+					<linkXRef>false</linkXRef>
+					<sourceDirectories>src</sourceDirectories>
+				</configuration>
+			</plugin>
 		</plugins>
 	</build>
 

src/main/java/mate/academy/rickandmorty/config/DataLoader.java

@@ -0,0 +1,28 @@
+package mate.academy.rickandmorty.config;
+
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import mate.academy.rickandmorty.mapper.CharacterMapper;
+import mate.academy.rickandmorty.model.Character;
+import mate.academy.rickandmorty.repository.CharacterRepository;
+import mate.academy.rickandmorty.service.impl.DataFetchServiceImpl;
+import org.springframework.boot.ApplicationArguments;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.stereotype.Component;
+
+@Component
+@RequiredArgsConstructor
+public class DataLoader implements ApplicationRunner {
+    private final DataFetchServiceImpl dataFetcher;
+    private final CharacterMapper characterMapper;
+    private final CharacterRepository characterRepository;
+
+    @Override
+    public void run(ApplicationArguments args) {
+        List<Character> characters = dataFetcher.fetch()
+                .stream()
+                .map(characterMapper::toModel)
+                .toList();
+        characterRepository.saveAll(characters);
+    }
+}

src/main/java/mate/academy/rickandmorty/config/MapperConfig.java

@@ -0,0 +1,12 @@
+package mate.academy.rickandmorty.config;
+
+import org.mapstruct.InjectionStrategy;
+import org.mapstruct.NullValueCheckStrategy;
+
+@org.mapstruct.MapperConfig(
+        componentModel = "spring",
+        injectionStrategy = InjectionStrategy.CONSTRUCTOR,
+        nullValueCheckStrategy = NullValueCheckStrategy.ALWAYS,
+        implementationPackage = "<PACKAGE_NAME>.impl")
+public class MapperConfig {
+}

src/main/java/mate/academy/rickandmorty/dto/FetchedDataDto.java

@@ -0,0 +1,12 @@
+package mate.academy.rickandmorty.dto;
+
+import java.util.List;
+import lombok.Data;
+import mate.academy.rickandmorty.dto.jsonmapping.CharacterMappingDto;
+import mate.academy.rickandmorty.dto.jsonmapping.InfoMappingDto;
+
+@Data
+public class FetchedDataDto {
+    private InfoMappingDto info;
+    private List<CharacterMappingDto> results;
+}

src/main/java/mate/academy/rickandmorty/dto/jsonmapping/CharacterMappingDto.java

@@ -0,0 +1,11 @@
+package mate.academy.rickandmorty.dto.jsonmapping;
+
+import lombok.Data;
+
+@Data
+public class CharacterMappingDto {
+    private int id;
+    private String name;
+    private String status;
+    private String gender;
+}

src/main/java/mate/academy/rickandmorty/dto/jsonmapping/InfoMappingDto.java

@@ -0,0 +1,11 @@
+package mate.academy.rickandmorty.dto.jsonmapping;
+
+import lombok.Data;
+
+@Data
+public class InfoMappingDto {
+    private int count;
+    private int pages;
+    private String next;
+    private String prev;
+}

src/main/java/mate/academy/rickandmorty/mapper/CharacterMapper.java

@@ -0,0 +1,14 @@
+package mate.academy.rickandmorty.mapper;
+
+import mate.academy.rickandmorty.config.MapperConfig;
+import mate.academy.rickandmorty.dto.jsonmapping.CharacterMappingDto;
+import mate.academy.rickandmorty.model.Character;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+
+@Mapper(config = MapperConfig.class)
+public interface CharacterMapper {
+    @Mapping(target = "externalId", source = "id")
+    @Mapping(target = "id", ignore = true)
+    Character toModel(CharacterMappingDto characterDto);
+}

src/main/java/mate/academy/rickandmorty/service/DataFetchService.java

@@ -0,0 +1,8 @@
+package mate.academy.rickandmorty.service;
+
+import java.util.List;
+import mate.academy.rickandmorty.dto.jsonmapping.CharacterMappingDto;
+
+public interface DataFetchService {
+    List<CharacterMappingDto> fetch();
+}

src/main/java/mate/academy/rickandmorty/service/impl/CharacterServiceImpl.java

@@ -2,7 +2,6 @@
 
 import jakarta.transaction.Transactional;
 import java.util.List;
-import java.util.Optional;
 import java.util.Random;
 import lombok.RequiredArgsConstructor;
 import mate.academy.rickandmorty.model.Character;
@@ -21,8 +20,7 @@ public class CharacterServiceImpl implements CharacterService {
     public Character generateRandomCharacter() {
         long charactersAmount = characterRepository.count();
         long id = random.nextLong(charactersAmount);
-        return Optional.of(characterRepository.findById(id))
-                .get()
+        return characterRepository.findById(id)
                 .orElseThrow(() -> new IllegalStateException("Character not found with id: " + id));
     }
 

src/main/java/mate/academy/rickandmorty/service/impl/DataFetchServiceImpl.java

@@ -0,0 +1,41 @@
+package mate.academy.rickandmorty.service.impl;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import mate.academy.rickandmorty.dto.FetchedDataDto;
+import mate.academy.rickandmorty.dto.jsonmapping.CharacterMappingDto;
+import mate.academy.rickandmorty.service.DataFetchService;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestTemplate;
+
+@Component
+@RequiredArgsConstructor
+public class DataFetchServiceImpl implements DataFetchService {
+    private final RestTemplate restTemplate;
+    private final ObjectMapper objectMapper;
+    @Value("${characters.url}")
+    private String characterUrl;
+    private final List<CharacterMappingDto> characterDtos;
+
+    @Override
+    public List<CharacterMappingDto> fetch() {
+        String url = characterUrl;
+
+        while (url != null) {
+            String jsonResponse = restTemplate.getForObject(url, String.class);
+            try {
+                FetchedDataDto fetchedDataDto = objectMapper
+                        .readValue(jsonResponse, FetchedDataDto.class);
+                characterDtos.addAll(fetchedDataDto.getResults());
+                url = fetchedDataDto.getInfo().getNext();
+            } catch (JsonProcessingException e) {
+                throw new RuntimeException("Can't fetch all characters");
+            }
+        }
+
+        return characterDtos;
+    }
+}

src/test/java/mate/academy/rickandmorty/ApplicationTests.java

@@ -6,8 +6,8 @@
 @SpringBootTest
 class ApplicationTests {
 
-	@Test
-	void contextLoads() {
-	}
+    @Test
+    void contextLoads() {
+    }
 
 }