application/model/src/main/java/org/fuseri/model/dto/certificate/CertificateCreateDto.java

+package org.fuseri.model.dto.certificate;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotNull;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.course.CourseDto;
+import org.fuseri.model.dto.user.UserDto;
+
+
+/**
+ * This class represents a Data Transfer Object (DTO) for creating Certificate entities.
+ * It is used for creating Certificate entity.
+ */
+@Getter
+@Setter
+public class CertificateCreateDto {
+    @NotNull
+    @Valid
+    private UserDto user;
+    @NotNull
+    @Valid
+    private CourseDto course;
+
+    public CertificateCreateDto(UserDto user, CourseDto course) {
+        this.user = user;
+        this.course = course;
+    }
+}

application/model/src/main/java/org/fuseri/model/dto/certificate/CertificateDto.java

+package org.fuseri.model.dto.certificate;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.common.DomainObjectDto;
+import org.fuseri.model.dto.course.CourseDto;
+import org.fuseri.model.dto.user.UserDto;
+
+import java.time.Instant;
+
+/**
+ * This class represents a Data Transfer Object (DTO) for Certificate entities.
+ * It is used to transfer Certificate data between different layers of the application.
+ * It extends the DomainObjectDto class and includes additional Certificate-specific fields.
+ */
+@Getter
+@Setter
+public class CertificateDto extends DomainObjectDto {
+    @NotBlank
+    @NotNull
+    private UserDto user;
+    @NotBlank
+    @NotNull
+    private Instant generatedAt;
+    @NotNull
+    @Valid
+    private CourseDto course;
+    @NotNull
+    @Valid
+    private CertificateFileDto certificateFile;
+
+    public CertificateDto() {
+        setId("0");
+    }
+}

application/model/src/main/java/org/fuseri/model/dto/certificate/CertificateFileDto.java

+package org.fuseri.model.dto.certificate;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.common.DomainObjectDto;
+
+
+/**
+ * This class represents a Data Transfer Object (DTO) for Certificate file.
+ * It is used to transfer Certificate file between different layers of the application.
+ * It extends the DomainObjectDto class and includes additional CertificateFile-specific fields.
+ */
+@Getter
+@Setter
+public class CertificateFileDto extends DomainObjectDto {
+    @NotBlank
+    @NotNull
+    private String filename;
+    @NotBlank
+    @NotNull
+    private String fileContentBase64;
+}
+

application/model/src/main/java/org/fuseri/model/dto/common/DomainObjectDto.java

 package org.fuseri.model.dto.common;
 
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
 import lombok.Getter;
 import lombok.Setter;
 
@@ -7,5 +9,7 @@ import lombok.Setter;
 @Setter
 public abstract class DomainObjectDto {
 
+    @NotBlank
+    @NotNull
     private String id;
 }

application/model/src/main/java/org/fuseri/model/dto/course/CourseCreateDto.java

+package org.fuseri.model.dto.course;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * This class represents a Data Transfer Object (DTO) for Course entities.
+ * It is used to create a new Course with the init data.
+ */
+@Getter
+@Setter
+@AllArgsConstructor
+public class CourseCreateDto {
+
+    @NotBlank(message = "Course name is required")
+    @Size(max = 50, message = "Course name must not exceed {max} characters")
+    private String name;
+
+    @NotNull(message = "Lecture capacity cannot be null")
+    @Min(value = 1, message = "Lecture capacity must be at least 1")
+    private Integer capacity;
+
+    @NotNull(message = "Language type is required")
+    @Valid
+    private LanguageTypeDto languageTypeDto;
+
+    @NotNull(message = "Proficiency level is required")
+    @Valid
+    private ProficiencyLevelDto proficiencyLevelDto;
+
+}

application/model/src/main/java/org/fuseri/model/dto/course/CourseDto.java

+package org.fuseri.model.dto.course;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.common.DomainObjectDto;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class represents a Data Transfer Object (DTO) for Course entities.
+ * It is used to transfer Course data between different layers of the application.
+ * It extends the DomainObjectDto class and includes additional Course-specific fields.
+ */
+@Getter
+@Setter
+@EqualsAndHashCode
+public class CourseDto extends DomainObjectDto {
+
+    @NotBlank(message = "Course name is required")
+    @Size(max = 63, message = "Course name must not exceed {max} characters")
+    private String name;
+
+    @NotNull(message = "Lecture capacity cannot be null")
+    @Min(value = 1, message = "Lecture capacity must be at least 1")
+    private Integer capacity;
+
+    @NotNull(message = "Language type is required")
+    @Valid
+    private LanguageTypeDto languageTypeDto;
+
+    @NotNull(message = "Proficiency level is required")
+    @Valid
+    private ProficiencyLevelDto proficiencyLevelDto;
+
+    @NotNull(message = "Student's list is required")
+    @Valid
+    private List<String> studentIds;
+
+    public CourseDto(String name, Integer capacity, LanguageTypeDto languageTypeDto, ProficiencyLevelDto proficiencyLevelDto) {
+        setId("0");
+        this.name = name;
+        this.capacity = capacity;
+        this.languageTypeDto = languageTypeDto;
+        this.proficiencyLevelDto = proficiencyLevelDto;
+        this.studentIds = new ArrayList<>();
+    }
+}

application/model/src/main/java/org/fuseri/model/dto/course/LanguageTypeDto.java

+package org.fuseri.model.dto.course;
+
+public enum LanguageTypeDto {
+    ENGLISH,
+    GERMAN,
+    SPANISH,
+    CZECH
+}

application/model/src/main/java/org/fuseri/model/dto/course/ProficiencyLevelDto.java

+package org.fuseri.model.dto.course;
+
+public enum ProficiencyLevelDto {
+    A1,
+    A2,
+    B1,
+    B2,
+    C1,
+    C2
+}

application/model/src/main/java/org/fuseri/model/dto/lecture/LectureCreateDto.java

+package org.fuseri.model.dto.lecture;
+
+import jakarta.validation.constraints.*;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.course.CourseDto;
+
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
+public class LectureCreateDto {
+
+    @Future(message = "Lecture start date and time must be in the future")
+    @NotNull(message = "Lecture start date and time cannot be null")
+    private LocalDateTime from;
+
+    @Future(message = "Lecture end date and time must be in the future")
+    @NotNull(message = "Lecture end date and time cannot be null")
+    private LocalDateTime to;
+
+    @NotBlank(message = "Lecture topic cannot be blank")
+    @Size(max = 255, message = "Lecture topic must be no more than {max} characters")
+    private String topic;
+
+    @NotNull(message = "Lecture capacity cannot be null")
+    @Min(value = 1, message = "Lecture capacity must be at least 1")
+    private Integer capacity;
+
+    @NotBlank(message = "Lecture course cannot be blank")
+    private String courseId;
+
+    public LectureCreateDto(LocalDateTime from, LocalDateTime to, String topic, Integer capacity, String courseId) {
+        this.from = from;
+        this.to = to;
+        this.topic = topic;
+        this.capacity = capacity;
+        this.courseId = courseId;
+    }
+
+    @AssertTrue(message = "Lecture start datetime must be before Lecture end datetime")
+    private boolean isFromDateBeforeToDate() {
+        if (from == null || to == null) return true;
+        return from.isBefore(to);
+    }
+}

application/model/src/main/java/org/fuseri/model/dto/lecture/LectureDto.java

+package org.fuseri.model.dto.lecture;
+
+import jakarta.validation.constraints.*;
+import lombok.Getter;
+import lombok.Setter;
+import org.fuseri.model.dto.common.DomainObjectDto;
+
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+@Getter
+@Setter
+public class LectureDto extends DomainObjectDto {
+
+    @Future(message = "Lecture start date and time must be in the future")
+    @NotNull(message = "Lecture start date and time cannot be null")
+    private LocalDateTime from;
+
+    @Future(message = "Lecture end date and time must be in the future")
+    @NotNull(message = "Lecture end date and time cannot be null")
+    private LocalDateTime to;
+
+    @NotBlank(message = "Lecture topic cannot be blank")
+    @Size(max = 255, message = "Lecture topic must be no more than {max} characters")
+    private String topic;
+
+    @NotNull(message = "Lecture capacity cannot be null")
+    @Min(value = 1, message = "Lecture capacity must be at least 1")
+    private Integer capacity;
+
+    @NotNull(message = "Lecture capacity cannot be null")
+    private String lecturerId;
+
+    @NotBlank(message = "Lecture courseId cannot be blank")
+    private String courseId;
+
+    @NotNull(message = "Student IDs list cannot be null")
+    private List<String> studentIds;
+
+    public LectureDto(LocalDateTime from, LocalDateTime to, String topic, Integer capacity, String lecturerId, String courseId) {
+        this.from = from;
+        this.to = to;
+        this.topic = topic;
+        this.capacity = capacity;
+        this.lecturerId = lecturerId;
+        this.courseId = courseId;
+        this.studentIds = new ArrayList<>();
+    }
+
+    @AssertTrue(message = "Lecture start datetime must be before Lecture end datetime")
+    private boolean isFromDateBeforeToDate() {
+        if (from == null || to == null) return true;
+        return from.isBefore(to);
+    }
+}

application/model/src/main/java/org/fuseri/model/dto/user/UserDto.java

@@ -17,4 +17,14 @@ public class UserDto extends DomainObjectDto {
     private String lastName;
 
     private AddressDto address;
+
+
+    public UserDto(String username, String email, String firstName, String lastName, AddressDto address) {
+        setId("0");
+        this.username = username;
+        this.email = email;
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.address = address;
+    }
 }

application/module-certificate/pom.xml

@@ -27,6 +27,42 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.fuseri</groupId>
+            <artifactId>models</artifactId>
+            <version>0.0.1-SNAPSHOT</version>
+            <scope>compile</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>2.0.2</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

application/module-certificate/src/main/java/org/fuseri/modulecertificate/ModuleCertificateApplication.java

@@ -6,6 +6,8 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 @SpringBootApplication
 public class ModuleCertificateApplication {
 
+    //mvn clean install
+    //java -jar .\module-certificate\target\module-certificate-0.0.1-SNAPSHOT.jar
     public static void main(String[] args) {
         SpringApplication.run(ModuleCertificateApplication.class, args);
     }

application/module-certificate/src/main/java/org/fuseri/modulecertificate/service/CertificateController.java

+package org.fuseri.modulecertificate.service;
+
+import jakarta.validation.Valid;
+import org.fuseri.model.dto.certificate.CertificateCreateDto;
+import org.fuseri.model.dto.certificate.CertificateDto;
+import org.fuseri.model.dto.common.Result;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+/**
+ * This class represents a RESTful controller for Certificate module.
+ * It handles incoming HTTP requests for generating and retrieving course certificates,
+ * and delegates them to the appropriate service method.
+ */
+@RestController
+@RequestMapping("/certificates")
+public class CertificateController {
+
+    @Autowired
+    public CertificateController() {
+    }
+
+    /**
+     * Generates certificate for specified user and course.
+     *
+     * @param certificateCreateDto Dto with data used for generating certificate
+     * @return CertificateDto with data of generated certificate
+     */
+    @PostMapping("/generate")
+    public CertificateDto generate(@Valid @RequestBody CertificateCreateDto certificateCreateDto) {
+        return new CertificateDto();
+    }
+
+    /**
+     * Retrieves previously generated certificate.
+     *
+     * @param id ID of certificate to be retrieved
+     * @return CertificateDto with data of previously generated certificate with specified ID
+     */
+    @GetMapping("/find")
+    public CertificateDto find(@RequestParam String id) {
+        return new CertificateDto();
+    }
+
+    /**
+     * Retrieves previously generated certificates for user.
+     *
+     * @param userId ID of user to retrieve certificates for.
+     * @return List of CertificateDto objects with previously generated certificates
+     * for specified User.
+     */
+    @GetMapping("/findForUser")
+    public List<CertificateDto> findForUser(@RequestParam String userId) {
+        return List.of(new CertificateDto());
+    }
+
+    /**
+     * Retrieves previously generated certificate ID.
+     *
+     * @param userId   ID of user to retrieve certificates for.
+     * @param courseId ID of course to retrieve certificates for.
+     * @return List of CertificateDto objects with previously generated certificates
+     * for specified User.
+     */
+    @GetMapping("/getId")
+    public String getId(@RequestParam String userId, @RequestParam String courseId) {
+        return "0";
+    }
+
+    /**
+     * Retrieves previously generated certificate ID.
+     *
+     * @param id Id of certificate to be deleted.
+     */
+    @DeleteMapping("/delete")
+    public void delete(@RequestParam String id) {
+    }
+
+    /**
+     * Find certificates and return them in a paginated format
+     *
+     * @param page the page number of the certificates to retrieve
+     * @return a Result object containing a list of CertificateDto objects and pagination information
+     */
+    @GetMapping("/findAll")
+    public Result<CertificateDto> findAllCertificates(@RequestParam int page) {
+        return new Result<>();
+    }
+}

application/module-certificate/src/test/java/org/fuseri/modulecertificate/CertificateControllerTests.java

+package org.fuseri.modulecertificate;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.fuseri.model.dto.certificate.CertificateCreateDto;
+import org.fuseri.model.dto.certificate.CertificateDto;
+import org.fuseri.model.dto.course.CourseDto;
+import org.fuseri.model.dto.course.LanguageTypeDto;
+import org.fuseri.model.dto.course.ProficiencyLevelDto;
+import org.fuseri.model.dto.user.AddressDto;
+import org.fuseri.model.dto.user.UserDto;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class CertificateControllerTests {
+
+    @Autowired
+    private ObjectMapper objectMapper;
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    private final UserDto USER = new UserDto("novakovat",
+            "novakova@gamil.com", "Tereza", "Nováková", new AddressDto());
+    private final CourseDto COURSE = new CourseDto("AJ1", 10,
+            LanguageTypeDto.ENGLISH, ProficiencyLevelDto.A1);
+
+    @Test
+    void generateCertificate() throws Exception {
+        mockMvc.perform(post("/certificates/generate")
+                        .content(asJsonString(new CertificateCreateDto(USER, COURSE)))
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isOk());
+    }
+
+    @Test
+    void generateCertificateWithNullUser() throws Exception {
+        mockMvc.perform(post("/certificates/generate")
+                        .content(asJsonString(new CertificateCreateDto(null, COURSE)))
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void generateCertificateWithNullCourse() throws Exception {
+        mockMvc.perform(post("/certificates/generate")
+                        .content(asJsonString(new CertificateCreateDto(USER, null)))
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void generateCertificateWithoutParams() throws Exception {
+        mockMvc.perform(post("/certificates/generate")
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void findCertificate() throws Exception {
+        String response = mockMvc.perform(post("/certificates/generate")
+                        .content(asJsonString(new CertificateCreateDto(USER, COURSE)))
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isOk()).andReturn().getResponse().getContentAsString();
+
+        String id = objectMapper.readValue(response, CertificateDto.class).getId();
+
+        mockMvc.perform(get("/certificates/find").param("id", id))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.id").value(id));
+    }
+
+    @Test
+    void findCertificateWithoutId() throws Exception {
+        mockMvc.perform(get("/certificates/find"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void findCertificatesForUser() throws Exception {
+        mockMvc.perform(get("/certificates/findForUser").param("userId", "0"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$").isArray())
+                .andExpect(jsonPath("$").isNotEmpty());
+    }
+
+    @Test
+    void findCertificatesWithoutUserId() throws Exception {
+        mockMvc.perform(get("/certificates/findForUser"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void findCertificateIdForUserAndCourse() throws Exception {
+        mockMvc.perform(get("/certificates/getId")
+                        .param("userId", "0")
+                        .param("courseId", "0"))
+                .andExpect(status().isOk())
+                .andExpect(content().string("0"));
+    }
+
+    @Test
+    void findCertificateIdWithoutUserId() throws Exception {
+        mockMvc.perform(get("/certificates/getId")
+                        .param("courseId", "0"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void findCertificateIdWithoutCourseId() throws Exception {
+        mockMvc.perform(get("/certificates/getId")
+                        .param("userId", "0"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void findCertificateIdWithoutParams() throws Exception {
+        mockMvc.perform(get("/certificates/getId"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    @Test
+    void deleteCertificate() throws Exception {
+        mockMvc.perform(delete("/certificates/delete")
+                        .param("id", "0"))
+                .andExpect(status().isOk());
+    }
+
+    @Test
+    void deleteCertificateWithoutParam() throws Exception {
+        mockMvc.perform(delete("/certificates/delete"))
+                .andExpect(status().is4xxClientError());
+    }
+
+
+    @Test
+    void findAllCertificates() throws Exception {
+        mockMvc.perform(get("/certificates/findAll")
+                        .param("page", "1"))
+                .andExpect(status().isOk());
+    }
+
+    @Test
+    void findAllCertificatesWithoutParam() throws Exception {
+        mockMvc.perform(get("/certificates/findAll"))
+                .andExpect(status().is4xxClientError());
+    }
+
+    private static String asJsonString(final Object obj) {
+        try {
+            return new ObjectMapper().writeValueAsString(obj);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

application/module-language-school/pom.xml

@@ -22,6 +22,11 @@
 			<artifactId>spring-boot-starter</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-validation</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>
@@ -44,11 +49,19 @@
 			<scope>runtime</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>com.fasterxml.jackson.datatype</groupId>
+			<artifactId>jackson-datatype-jsr310</artifactId>
+			<version>2.14.2</version>
+		</dependency>
+
 		<dependency>
 			<groupId>org.fuseri</groupId>
 			<artifactId>models</artifactId>
 			<version>0.0.1-SNAPSHOT</version>
 		</dependency>
+
+
 	</dependencies>
 
 	<build>

application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/common/DomainObject.java

 package org.fuseri.modulelanguageschool.common;
+
 import jakarta.persistence.Id;
 import jakarta.persistence.MappedSuperclass;
 import lombok.Getter;

application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/Course.java

+package org.fuseri.modulelanguageschool.course;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import lombok.*;
+import org.fuseri.modulelanguageschool.common.DomainObject;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class Course extends DomainObject {
+
+    private String name;
+    private Integer capacity;
+
+    @Enumerated(EnumType.STRING)
+    private Language language;
+
+    @Enumerated(EnumType.STRING)
+    private ProficiencyLevel proficiencyLevel;
+}

application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/CourseController.java

+package org.fuseri.modulelanguageschool.course;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.PositiveOrZero;
+import org.fuseri.model.dto.course.CourseCreateDto;
+import org.fuseri.model.dto.course.CourseDto;
+import org.fuseri.model.dto.course.LanguageTypeDto;
+import org.fuseri.model.dto.course.ProficiencyLevelDto;
+import org.fuseri.model.dto.user.UserDto;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class represents a RESTful controller for Courses resources.
+ * It handles incoming HTTP requests related to courses, and delegates them to the appropriate service method.
+ */
+@RestController
+@RequestMapping("/courses")
+public class CourseController {
+
+    public static final String COURSE_NAME = "english b2 course";
+
+    /**
+     * Creates a new course.
+     *
+     * @param dto the CourseCreateDto containing the course data
+     * @return the newly created CourseDto
+     */
+    @PostMapping("/create")
+    public CourseDto create(@Valid @RequestBody CourseCreateDto dto) {
+        return new CourseDto(dto.getName(), dto.getCapacity(), dto.getLanguageTypeDto(), dto.getProficiencyLevelDto());
+    }
+
+    /**
+     * Retrieves a course by ID.
+     *
+     * @param id the ID of the course to retrieve
+     * @return the CourseDto for the specified ID
+     */
+    @GetMapping("/find/{id}")
+    public CourseDto find(@PathVariable String id) {
+        return new CourseDto(COURSE_NAME, 10, LanguageTypeDto.ENGLISH, ProficiencyLevelDto.B2);
+    }
+
+    /**
+     * Retrieves a paginated list of courses
+     *
+     * @param page the page number to retrieve
+     * @return the Result containing the requested page of CourseDtos
+     */
+    @GetMapping("/findAll")
+    public List<CourseDto> findAll(@RequestParam int page) {
+        return new ArrayList<>();
+    }
+
+    /**
+     * Retrieves a paginated list of courses of a given language
+     *
+     * @param page the page number to retrieve
+     * @param lang the language to find courses of
+     * @return the Result containing the requested page of CourseDtos
+     */
+    @GetMapping("/findAllByLang")
+    public List<CourseDto> findAll(@RequestParam int page, @RequestParam LanguageTypeDto lang) {
+        return new ArrayList<>();
+    }
+
+    /**
+     * Retrieves a paginated list of courses of a given language and proficiency
+     *
+     * @param page the page number to retrieve
+     * @param lang the language to find courses of
+     * @param prof the proficiency of the language
+     * @return the Result containing the requested page of CourseDtos
+     */
+    @GetMapping("/findAllByLangProf")
+    public List<CourseDto> findAll(@RequestParam int page,
+                                   @RequestParam LanguageTypeDto lang,
+                                   @RequestParam ProficiencyLevelDto prof) {
+        return new ArrayList<>();
+    }
+
+    /**
+     * Updates an existing course.
+     *
+     * @param id  the ID of the course to update
+     * @param dto the CourseCreateDto containing the updated course data
+     * @return the updated CourseDto
+     */
+    @PutMapping("/update/{id}")
+    public CourseDto update(@PathVariable String id, @Valid @RequestBody CourseCreateDto dto) {
+        return new CourseDto(dto.getName(), dto.getCapacity(), dto.getLanguageTypeDto(), dto.getProficiencyLevelDto());
+    }
+
+    /**
+     * Deletes a course by ID.
+     *
+     * @param id the ID of the course to delete
+     * @return true if the course was successfully deleted, false otherwise
+     */
+    @DeleteMapping("/delete/{id}")
+    public void delete(@PathVariable String id) {
+    }
+
+
+    /**
+     * Adds student to the existing course
+     *
+     * @param id      id of course to update
+     * @param student UserDto for the student
+     * @return the CourseDto representing the updated course
+     */
+    @PatchMapping("/enrol/{id}")
+    public CourseDto enrol(@PathVariable String id, @RequestBody UserDto student) {
+        var course = new CourseDto(COURSE_NAME, 10, LanguageTypeDto.ENGLISH, ProficiencyLevelDto.B2);
+        course.setStudentIds(new ArrayList<>(List.of(student.getId())));
+        return course;
+    }
+
+    /**
+     * Removes student from the existing course
+     *
+     * @param id      id of lecture to update
+     * @param student UserDto for the student
+     * @return the CourseDto representing the updated course
+     */
+    @PatchMapping("/expel/{id}")
+    public CourseDto expel(@PathVariable String id, @RequestBody UserDto student) {
+        return new CourseDto(COURSE_NAME, 10, LanguageTypeDto.ENGLISH, ProficiencyLevelDto.B2);
+    }
+
+}

application/module-language-school/src/main/java/org/fuseri/modulelanguageschool/course/Language.java

+package org.fuseri.modulelanguageschool.course;
+
+/**
+ * An enum representing individual languages.
+ */
+public enum Language {
+
+    ENGLISH("English"),
+    GERMAN("Deutsch"),
+    SPANISH("Español"),
+    CZECH("Čeština");
+
+    private final String nativeName;
+
+    /**
+     * Constructor for Language enum.
+     *
+     * @param nativeName a String representing the native name of the language
+     */
+    Language(String nativeName) {
+        this.nativeName = nativeName;
+    }
+
+    /**
+     * Returns the native name of the language.
+     *
+     * @return a String representing the native name of the language
+     */
+    public String getNativeName() {
+        return nativeName;
+    }
+}