add spock reports

Polishing

Dockerfile

@@ -8,4 +8,4 @@ RUN mvn -B -f pom.xml clean package -DskipTests
 FROM openjdk:11-jdk-slim
 COPY --from=build /workspace/target/*.jar app.jar
 EXPOSE 8080
-ENTRYPOINT ["java","-jar","app.jar"]
+ENTRYPOINT ["java","-jar","app.jar", "--spring.profiles.active=prod"]

README.md

@@ -19,14 +19,23 @@ In the terminal run the following command:
 $ docker-compose up
 ``` 
 
-#### Using Maven
+#### Using Maven (with H2 or local Postgres database)
 
-First make sure that you adjust the configuration file - `src/main/resources/application.yml` with connection details to your database.  
+First compile an application:
 
-Then, in the terminal run the following command:
 ```console
 $ mvn clean package
-$ mvn spring-boot:run
+```
+
+Then, you have two options either run it with H2 database or with local Postgres database. For first approach just run:
+
+```console
+$ mvn spring-boot:run 
+```
+
+For a second option, check in the configuration file - `src/main/resources/application.yml` for profile *local-postgres* if connection details are correct and if so, run the command:
+```console
+$ mvn spring-boot:run -P local-postgres
 ```
 
 #### Inside IntelliJ (with H2 or Postgres database)

pom.xml

@@ -6,7 +6,7 @@
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
 		<version>2.2.6.RELEASE</version>
-		<relativePath/> <!-- lookup parent from repository -->
+		<relativePath/>
 	</parent>
 
 	<groupId>io.wkrzywiec.hexagonal</groupId>
@@ -17,11 +17,14 @@
 
 	<properties>
 		<java.version>11</java.version>
-		<spring-cloud.version>Hoxton.M3</spring-cloud.version>
 		<surefire.and.failsafe.report.dir>target/test-report</surefire.and.failsafe.report.dir>
 		<code.coverage.exclusions>
-			**/io/wkrzywiec/hexagonal/library/domain/book/dto/**,
-			**/io/wkrzywiec/hexagonal/library/infrastructure/repository/*Entity.java
+			**/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/**,
+			**/io/wkrzywiec/hexagonal/library/domain/email/core/model/**,
+			**/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/**,
+			**/io/wkrzywiec/hexagonal/library/domain/user/core/model/**,
+			**/io/wkrzywiec/hexagonal/library/**/*Entity.java,
+			**/io/wkrzywiec/hexagonal/library/LibraryHexagonalApplication.java
 		</code.coverage.exclusions>
 	</properties>
 
@@ -30,6 +33,10 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-web</artifactId>
@@ -55,11 +62,6 @@
 			<artifactId>jackson-module-jaxb-annotations</artifactId>
 			<version>2.11.0</version>
 		</dependency>
-		<dependency>
-			<groupId>io.vavr</groupId>
-			<artifactId>vavr</artifactId>
-			<version>0.10.3</version>
-		</dependency>
 
 		<dependency>
 			<groupId>com.h2database</groupId>
@@ -89,27 +91,48 @@
 			<version>1.2.32</version>
 		</dependency>
 
+		<!--	TEST dependencies	-->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.spockframework</groupId>
+			<artifactId>spock-core</artifactId>
+			<version>1.3-groovy-2.5</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.spockframework</groupId>
+			<artifactId>spock-spring</artifactId>
+			<version>1.3-groovy-2.5</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>com.athaydes</groupId>
+			<artifactId>spock-reports</artifactId>
+			<version>1.8.0</version>
+			<scope>test</scope>
 			<exclusions>
 				<exclusion>
-					<groupId>org.junit.vintage</groupId>
-					<artifactId>junit-vintage-engine</artifactId>
+					<groupId>*</groupId>
+					<artifactId>*</artifactId>
 				</exclusion>
 			</exclusions>
 		</dependency>
+		<dependency>
+			<groupId>io.rest-assured</groupId>
+			<artifactId>rest-assured</artifactId>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>com.tngtech.archunit</groupId>
 			<artifactId>archunit-junit5</artifactId>
 			<version>0.13.1</version>
 			<scope>test</scope>
 		</dependency>
-		<dependency>
-			<groupId>io.rest-assured</groupId>
-			<artifactId>rest-assured</artifactId>
-		</dependency>
+
 	</dependencies>
 
 	<build>
@@ -142,8 +165,25 @@
 				<artifactId>maven-surefire-plugin</artifactId>
 				<configuration>
 					<reportsDirectory>${surefire.and.failsafe.report.dir}</reportsDirectory>
+					<includes>
+						<include>**/*Spec.java</include>
+						<include>**/*Test.java</include>
+					</includes>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.codehaus.gmavenplus</groupId>
+				<artifactId>gmavenplus-plugin</artifactId>
+				<version>1.10.0</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>addTestSources</goal>
+							<goal>compileTests</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
 			<plugin>
 				<groupId>org.jacoco</groupId>
 				<artifactId>jacoco-maven-plugin</artifactId>
@@ -188,6 +228,33 @@
 	</build>
 
 	<profiles>
+		<profile>
+			<id>default</id>
+			<activation>
+				<activeByDefault>true</activeByDefault>
+			</activation>
+			<properties>
+				<active-profiles>default</active-profiles>
+			</properties>
+		</profile>
+		<profile>
+			<id>prod</id>
+			<activation>
+				<activeByDefault>false</activeByDefault>
+			</activation>
+			<properties>
+				<active-profiles>prod</active-profiles>
+			</properties>
+		</profile>
+		<profile>
+			<id>local-postgres</id>
+			<activation>
+				<activeByDefault>false</activeByDefault>
+			</activation>
+			<properties>
+				<active-profiles>local-postgres</active-profiles>
+			</properties>
+		</profile>
 		<profile>
 			<id>component-test</id>
 			<build>
@@ -234,6 +301,7 @@
 				<sonar.sources>.</sonar.sources>
 				<sonar.inclusions>src/main/java/**,src/main/resources/**</sonar.inclusions>
 				<sonar.exclusions>${code.coverage.exclusions}</sonar.exclusions>
+				<sonat.tests>src/test/groovy,src/test/java</sonat.tests>
 				<sonar.projectKey>wkrzywiec_library-hexagonal</sonar.projectKey>
 				<sonar.organization>wkrzywiec</sonar.organization>
 				<sonar.coverage.jacoco.xmlReportPaths>target/site/jacoco/jacoco.xml,target/site/jacoco-it/jacoco.xml</sonar.coverage.jacoco.xmlReportPaths>

src/component-test/java/io/wkrzywiec/hexagonal/library/DatabaseCleanup.java

@@ -1,42 +0,0 @@
-package io.wkrzywiec.hexagonal.library;
-
-import org.springframework.beans.factory.InitializingBean;
-import org.springframework.stereotype.Service;
-import org.springframework.transaction.annotation.Transactional;
-
-import javax.persistence.EntityManager;
-import javax.persistence.PersistenceContext;
-import javax.persistence.Table;
-import java.util.List;
-import java.util.stream.Collectors;
-
-//https://gist.github.com/JorgenRingen/a56837fc07e630c32280b8e3d14c2d24
-
-@Service
-public class DatabaseCleanup implements InitializingBean {
-
-    @PersistenceContext
-    private EntityManager entityManager;
-
-    private List<String> tableNames;
-
-    @Transactional
-    public void execute() {
-        entityManager.flush();
-        entityManager.createNativeQuery("SET REFERENTIAL_INTEGRITY FALSE").executeUpdate();
-
-        for (final String tableName : tableNames) {
-            entityManager.createNativeQuery("TRUNCATE TABLE " + tableName).executeUpdate();
-        }
-
-        entityManager.createNativeQuery("SET REFERENTIAL_INTEGRITY TRUE").executeUpdate();
-    }
-
-    @Override
-    public void afterPropertiesSet() throws Exception {
-        tableNames = entityManager.getMetamodel().getEntities().stream()
-                .filter(e -> e.getJavaType().getAnnotation(Table.class) != null)
-                .map(e -> e.getJavaType().getAnnotation(Table.class).name())
-                .collect(Collectors.toList());
-    }
-}

src/component-test/java/io/wkrzywiec/hexagonal/library/borrowing/MakeReservationComponentTest.java

@@ -1,96 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing;
-
-import io.wkrzywiec.hexagonal.library.DatabaseCleanup;
-import io.wkrzywiec.hexagonal.library.TestData;
-import io.wkrzywiec.hexagonal.library.borrowing.model.BookReservationCommand;
-import io.wkrzywiec.hexagonal.library.inventory.infrastructure.BookRepository;
-import io.wkrzywiec.hexagonal.library.inventory.model.Book;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.web.server.LocalServerPort;
-import org.springframework.jdbc.core.JdbcTemplate;
-
-import static io.restassured.RestAssured.given;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
-public class MakeReservationComponentTest {
-
-    @LocalServerPort
-    private int port;
-
-    @Autowired
-    private BookRepository bookRepository;
-
-    @Autowired
-    private JdbcTemplate jdbcTemplate;
-
-    @Autowired
-    private DatabaseCleanup databaseCleanup;
-
-
-    private String baseURL;
-
-    @BeforeEach
-    public void init() {
-        this.baseURL = "http://localhost:" + port;
-
-        Book book = bookRepository.save(TestData.homoDeusBook());
-        jdbcTemplate.update(
-                "INSERT INTO available (book_id) VALUES (?)",
-                book.getIdAsLong());
-
-        jdbcTemplate.update(
-                "INSERT INTO user (first_name, last_name, email) VALUES (?, ?, ?)",
-                "John",
-                "Doe",
-                "john.doe@test.com");
-    }
-
-    @AfterEach
-    public void after() {
-        databaseCleanup.execute();
-    }
-
-    @Test
-    @DisplayName("Reserve available book")
-    public void givenBookIsAvailable_thenMakeReservation_thenBookIsReserved() {
-        //given
-        Long homoDeusBookId = jdbcTemplate.queryForObject(
-                "SELECT id FROM book WHERE title = ?",
-                Long.class,
-                TestData.homoDeusBookTitle());
-
-        Long activeUserId = jdbcTemplate.queryForObject(
-                "SELECT id FROM user WHERE email = ?",
-                Long.class,
-                "john.doe@test.com");
-
-
-        BookReservationCommand reservationCommand =
-                BookReservationCommand.builder()
-                .bookId(homoDeusBookId )
-                .userId(activeUserId)
-                .build();
-
-        //when
-        given()
-                .contentType("application/json")
-                .body(reservationCommand)
-        .when()
-                .post( baseURL + "/reservations")
-                .prettyPeek()
-        .then();
-
-        Long reservationId = jdbcTemplate.queryForObject(
-                "SELECT id FROM reserved WHERE book_id = ?",
-                Long.class,
-                homoDeusBookId);
-
-        assertTrue(reservationId > 0);
-    }
-}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/BaseComponentTest.java

@@ -0,0 +1,28 @@
+package io.wkrzywiec.hexagonal.library.domain;
+
+import io.restassured.RestAssured;
+import io.wkrzywiec.hexagonal.library.DatabaseHelper;
+import org.junit.jupiter.api.BeforeEach;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.jdbc.core.JdbcTemplate;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public abstract class BaseComponentTest {
+
+    @LocalServerPort
+    private int port;
+    protected String baseURL;
+
+    @Autowired
+    protected JdbcTemplate jdbcTemplate;
+    protected DatabaseHelper databaseHelper;
+
+    @BeforeEach
+    public void init() {
+        this.baseURL = "http://localhost:" + port;
+        RestAssured.enableLoggingOfRequestAndResponseIfValidationFails();
+        databaseHelper = new DatabaseHelper(jdbcTemplate);
+    }
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/borrowing/BorrowBookComponentTest.java

@@ -0,0 +1,44 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing;
+
+import io.wkrzywiec.hexagonal.library.domain.BaseComponentTest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.BookStatus;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.ChangeBookStatusRequest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowBookCommand;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.test.context.jdbc.Sql;
+
+import static io.restassured.RestAssured.given;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.springframework.test.context.jdbc.Sql.ExecutionPhase.AFTER_TEST_METHOD;
+
+public class BorrowBookComponentTest extends BaseComponentTest {
+
+    @Test
+    @DisplayName("Borrow reserved book")
+    @Sql({"/book-and-user.sql", "/reserved-book.sql"})
+    @Sql(scripts = "/clean-database.sql", executionPhase = AFTER_TEST_METHOD)
+    public void givenBookIsReserved_thenBorrowIt_thenBookIsBorrowed() {
+        //given
+        Long homoDeusBookId = databaseHelper.getHomoDeusBookId();
+        Long activeUserId = databaseHelper.getJohnDoeUserId();
+
+        ChangeBookStatusRequest borrowRequest =
+                ChangeBookStatusRequest.builder()
+                .userId(activeUserId)
+                .status(BookStatus.BORROWED)
+                .build();
+
+        //when
+        given()
+                .contentType("application/json")
+                .body(borrowRequest)
+                .when()
+                .patch( baseURL + "/books/" + homoDeusBookId + "/status")
+                .prettyPeek()
+                .then();
+
+        Long borrowId = databaseHelper.getPrimaryKeyOfBorrowedByBookId(homoDeusBookId);
+        assertTrue(borrowId > 0);
+    }
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/borrowing/GiveBackBookComponentTest.java

@@ -0,0 +1,45 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing;
+
+import io.wkrzywiec.hexagonal.library.domain.BaseComponentTest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.BookStatus;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.ChangeBookStatusRequest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.GiveBackBookCommand;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.test.context.jdbc.Sql;
+
+import static io.restassured.RestAssured.given;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.springframework.test.context.jdbc.Sql.ExecutionPhase.AFTER_TEST_METHOD;
+
+public class GiveBackBookComponentTest extends BaseComponentTest {
+
+    @Test
+    @DisplayName("Give back borrowed book")
+    @Sql({"/book-and-user.sql", "/borrowed-book.sql"})
+    @Sql(scripts = "/clean-database.sql", executionPhase = AFTER_TEST_METHOD)
+    public void givenBookIsBorrowed_thenGiveBackIt_thenItIsAvailable() {
+        //given
+        Long homoDeusBookId = databaseHelper.getHomoDeusBookId();
+        Long activeUserId = databaseHelper.getJohnDoeUserId();
+
+        ChangeBookStatusRequest giveBackRequest =
+                ChangeBookStatusRequest.builder()
+                        .userId(activeUserId)
+                        .status(BookStatus.AVAILABLE)
+                        .build();
+
+        //when
+        given()
+                .contentType("application/json")
+                .body(giveBackRequest)
+                .when()
+                .patch( baseURL + "/books/" + homoDeusBookId + "/status")
+                .prettyPeek()
+                .then();
+
+        Long bookId = databaseHelper.getPrimaryKeyOfAvailableByBookBy(homoDeusBookId);
+
+        assertEquals(homoDeusBookId, bookId);
+    }
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/borrowing/MakeReservationComponentTest.java

@@ -0,0 +1,49 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing;
+
+import io.wkrzywiec.hexagonal.library.domain.BaseComponentTest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.BookStatus;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.ChangeBookStatusRequest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservationCommand;
+import io.wkrzywiec.hexagonal.library.domain.inventory.infrastructure.BookRepository;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.jdbc.Sql;
+
+import static io.restassured.RestAssured.given;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.springframework.test.context.jdbc.Sql.ExecutionPhase.AFTER_TEST_METHOD;
+
+public class MakeReservationComponentTest extends BaseComponentTest {
+
+    @Autowired
+    private BookRepository bookRepository;
+
+    @Test
+    @DisplayName("Reserve available book")
+    @Sql({"/book-and-user.sql", "/available-book.sql"})
+    @Sql(scripts = "/clean-database.sql", executionPhase = AFTER_TEST_METHOD)
+    public void givenBookIsAvailable_thenMakeReservation_thenBookIsReserved() {
+        //given
+        Long homoDeusBookId = databaseHelper.getHomoDeusBookId();
+        Long activeUserId = databaseHelper.getJohnDoeUserId();
+
+        ChangeBookStatusRequest reservationRequest =
+                ChangeBookStatusRequest.builder()
+                        .userId(activeUserId)
+                        .status(BookStatus.RESERVED)
+                        .build();
+
+        //when
+        given()
+                .contentType("application/json")
+                .body(reservationRequest)
+        .when()
+                .patch( baseURL + "/books/" + homoDeusBookId + "/status")
+                .prettyPeek()
+        .then();
+
+        Long reservationId = databaseHelper.getPrimaryKeyOfReservationByBookId(homoDeusBookId);
+        assertTrue(reservationId > 0);
+    }
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/inventory/AddNewBookComponentTest.java

@@ -0,0 +1,63 @@
+package io.wkrzywiec.hexagonal.library.domain.inventory;
+
+import io.restassured.response.ValidatableResponse;
+import io.wkrzywiec.hexagonal.library.BookTestData;
+import io.wkrzywiec.hexagonal.library.domain.BaseComponentTest;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.AddNewBookCommand;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpStatus;
+import org.springframework.test.context.jdbc.Sql;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.springframework.test.context.jdbc.Sql.ExecutionPhase.AFTER_TEST_METHOD;
+
+public class AddNewBookComponentTest extends BaseComponentTest {
+
+    @Test
+    @DisplayName("Search for a new book in Google Books")
+    public void whenSearchForBook_thenGetList(){
+        //when
+        ValidatableResponse response = given()
+                .when()
+                    .param("query", "lean startup")
+                    .get( baseURL + "/google/books")
+                    .prettyPeek()
+                .then();
+
+        //then
+        response.statusCode(HttpStatus.OK.value())
+                .contentType("application/json")
+                .body("items.size()", greaterThan(0));
+    }
+
+    @Test
+    @DisplayName("Add new book to a database & make it available")
+    @Sql(scripts = "/clean-database.sql", executionPhase = AFTER_TEST_METHOD)
+    public void givenGoogleBooId_whenAddNewBook_thenBookIsSaved() {
+        //given
+        AddNewBookCommand addNewBookCommand =
+                AddNewBookCommand.builder()
+                        .googleBookId(BookTestData.homoDeusBookGoogleId())
+                        .build();
+
+        //when
+        given()
+                .contentType("application/json")
+                .body(addNewBookCommand)
+        .when()
+                .post( baseURL + "/books")
+                .prettyPeek()
+        .then();
+
+        //then
+        Long savedBookId = databaseHelper.getHomoDeusBookId();
+        assertTrue(savedBookId > 0);
+
+        Long availableBookId = databaseHelper.getPrimaryKeyOfAvailableByBookBy(savedBookId);
+
+        assertTrue(availableBookId > 0);
+    }
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/domain/user/AddNewUserComponentTest.java

@@ -0,0 +1,40 @@
+package io.wkrzywiec.hexagonal.library.domain.user;
+
+import io.wkrzywiec.hexagonal.library.domain.BaseComponentTest;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.AddUserCommand;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.test.context.jdbc.Sql;
+
+import static io.restassured.RestAssured.given;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.springframework.test.context.jdbc.Sql.ExecutionPhase.AFTER_TEST_METHOD;
+
+public class AddNewUserComponentTest extends BaseComponentTest {
+
+    @Test
+    @DisplayName("Create new user")
+    @Sql(scripts = "/clean-database.sql", executionPhase = AFTER_TEST_METHOD)
+    public void shouldCreateNewUser(){
+        //given
+        AddUserCommand addUserCommand = AddUserCommand.builder()
+                .firstName("John")
+                .lastName("Doe")
+                .email("john.doe@test.com")
+                .build();
+
+        //when
+        given()
+                .contentType("application/json")
+                .body(addUserCommand)
+        .when()
+                .post( baseURL + "/users")
+                .prettyPeek()
+        .then();
+
+        //then
+        Long savedUserId = databaseHelper.getJohnDoeUserId();
+        assertTrue(savedUserId > 0);
+    }
+
+}

src/component-test/java/io/wkrzywiec/hexagonal/library/inventory/AddNewBookComponentTest.java

@@ -1,97 +0,0 @@
-package io.wkrzywiec.hexagonal.library.inventory;
-
-import io.restassured.RestAssured;
-import io.restassured.response.ValidatableResponse;
-import io.wkrzywiec.hexagonal.library.DatabaseCleanup;
-import io.wkrzywiec.hexagonal.library.TestData;
-import io.wkrzywiec.hexagonal.library.inventory.model.AddNewBookCommand;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.web.server.LocalServerPort;
-import org.springframework.http.HttpStatus;
-import org.springframework.jdbc.core.JdbcTemplate;
-
-import static io.restassured.RestAssured.given;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
-public class AddNewBookComponentTest {
-
-    @LocalServerPort
-    private int port;
-
-    @Autowired
-    private JdbcTemplate jdbc;
-
-    @Autowired
-    private DatabaseCleanup databaseCleanup;
-
-    private String baseURL;
-
-    @BeforeEach
-    public void init(){
-        this.baseURL = "http://localhost:" + port;
-        RestAssured.enableLoggingOfRequestAndResponseIfValidationFails();
-    }
-
-    @AfterEach
-    public void after() {
-        databaseCleanup.execute();
-    }
-
-    @Test
-    @DisplayName("Search for a new book in Google Books")
-    public void whenSearchForBook_thenGetList(){
-        //when
-        ValidatableResponse response = given()
-                .when()
-                    .param("query", "lean startup")
-                    .get( baseURL + "/google/books")
-                    .prettyPeek()
-                .then();
-
-        //then
-        response.statusCode(HttpStatus.OK.value())
-                .contentType("application/json")
-                .body("items.size()", greaterThan(0));
-    }
-
-    @Test
-    @DisplayName("Add new book to a database & make it available")
-    public void givenGoogleBooId_whenAddNewBook_thenBookIsSaved() {
-        //given
-        AddNewBookCommand addNewBookCommand =
-                AddNewBookCommand.builder()
-                        .googleBookId(TestData.homoDeusBookGoogleId())
-                        .build();
-
-        //when
-        given()
-                .contentType("application/json")
-                .body(addNewBookCommand)
-        .when()
-                .post( baseURL + "/books")
-                .prettyPeek()
-        .then();
-
-        //then
-        Long savedBookId = jdbc.queryForObject(
-                "SELECT id FROM book WHERE book_external_id = ?",
-                Long.class,
-                TestData.homoDeusBookGoogleId());
-
-        assertTrue(savedBookId > 0);
-
-        Long availableBookId = jdbc.queryForObject(
-                "SELECT id FROM available WHERE book_id = ?",
-                Long.class,
-                savedBookId);
-
-        assertTrue(availableBookId > 0);
-    }
-}

src/component-test/resources/application.yml

@@ -4,4 +4,4 @@ spring:
     driverClassName: org.h2.Driver
     username: sa
     password: password
-    jpa.database-platform: org.hibernate.dialect.H2Dialect
+    jpa.database-platform: org.hibernate.dialect.H2Dialect

src/main/java/io/wkrzywiec/hexagonal/library/BorrowingDomainConfig.java

@@ -1,23 +0,0 @@
-package io.wkrzywiec.hexagonal.library;
-
-import io.wkrzywiec.hexagonal.library.borrowing.BorrowingFacade;
-import io.wkrzywiec.hexagonal.library.borrowing.infrastructure.BorrowingDatabaseAdapter;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.incoming.MakeBookAvailable;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.outgoing.BorrowingDatabase;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.jdbc.core.JdbcTemplate;
-
-@Configuration
-public class BorrowingDomainConfig {
-
-    @Bean
-    public BorrowingDatabase borrowingDatabase(JdbcTemplate jdbcTemplate) {
-        return new BorrowingDatabaseAdapter(jdbcTemplate);
-    }
-
-    @Bean
-    public MakeBookAvailable makeBookAvailable(BorrowingDatabase database) {
-        return new BorrowingFacade(database);
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/LibraryHexagonalApplication.java

@@ -1,9 +1,24 @@
 package io.wkrzywiec.hexagonal.library;
 
+import io.wkrzywiec.hexagonal.library.infrastructure.BorrowingDomainConfig;
+import io.wkrzywiec.hexagonal.library.infrastructure.EmailDomainConfig;
+import io.wkrzywiec.hexagonal.library.infrastructure.InventoryDomainConfig;
+import io.wkrzywiec.hexagonal.library.infrastructure.LibraryHexagonalConfig;
+import io.wkrzywiec.hexagonal.library.infrastructure.UserDomainConfig;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Import;
+import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
+@EnableScheduling
+@Import({
+		LibraryHexagonalConfig.class,
+		InventoryDomainConfig.class,
+		BorrowingDomainConfig.class,
+		EmailDomainConfig.class,
+		UserDomainConfig.class
+})
 public class LibraryHexagonalApplication {
 
 	public static void main(String[] args) {

src/main/java/io/wkrzywiec/hexagonal/library/application/LibraryHexagonalController.java

@@ -0,0 +1,15 @@
+package io.wkrzywiec.hexagonal.library.application;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/")
+public class LibraryHexagonalController {
+
+    @GetMapping("")
+    public String getAppRoot(){
+        return "Library Hexagonal REST API";
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/BorrowingFacade.java

@@ -1,42 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.ActiveUser;
-import io.wkrzywiec.hexagonal.library.borrowing.model.MakeBookAvailableCommand;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservationDetails;
-import io.wkrzywiec.hexagonal.library.borrowing.model.exception.ActiveUserNotFoundException;
-import io.wkrzywiec.hexagonal.library.borrowing.model.AvailableBook;
-import io.wkrzywiec.hexagonal.library.borrowing.model.exception.AvailableBookNotFoundExeption;
-import io.wkrzywiec.hexagonal.library.borrowing.model.BookReservationCommand;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservedBook;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.incoming.MakeBookAvailable;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.incoming.ReserveBook;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.outgoing.BorrowingDatabase;
-
-public class BorrowingFacade implements MakeBookAvailable, ReserveBook {
-
-    private BorrowingDatabase database;
-
-    public BorrowingFacade(BorrowingDatabase database) {
-        this.database = database;
-    }
-
-    @Override
-    public void handle(MakeBookAvailableCommand bookAvailableCommand) {
-        database.setBookAvailable(bookAvailableCommand.getBookId());
-    }
-
-    @Override
-    public Long handle(BookReservationCommand bookReservation) {
-        AvailableBook availableBook =
-                database.getAvailableBook(bookReservation.getBookId())
-                .orElseThrow(() -> new AvailableBookNotFoundExeption(bookReservation.getBookId()));
-
-        ActiveUser activeUser =
-                database.getActiveUser(bookReservation.getUserId())
-                .orElseThrow(() -> new ActiveUserNotFoundException(bookReservation.getUserId()));
-
-        ReservedBook reservedBook = activeUser.reserve(availableBook);
-        ReservationDetails reservationDetails = database.save(reservedBook);
-        return reservationDetails.getReservationId().getIdAsLong();
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/application/ReservationController.java

@@ -1,25 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.application;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.BookReservationCommand;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.incoming.ReserveBook;
-import lombok.RequiredArgsConstructor;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.PostMapping;
-import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-@RestController
-@RequestMapping("/reservations")
-@RequiredArgsConstructor
-public class ReservationController {
-
-    private final ReserveBook reserveBook;
-
-    @PostMapping("")
-    public ResponseEntity<String> makeReservation(@RequestBody BookReservationCommand reservationCommand){
-        Long reservationId = reserveBook.handle(reservationCommand);
-        return new ResponseEntity<>("Reservation has been made with an id " + reservationId, HttpStatus.CREATED);
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/infrastructure/BorrowingDatabaseAdapter.java

@@ -1,82 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.infrastructure;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.ActiveUser;
-import io.wkrzywiec.hexagonal.library.borrowing.model.AvailableBook;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservationDetails;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservationId;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservedBook;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.outgoing.BorrowingDatabase;
-import lombok.AllArgsConstructor;
-import org.springframework.dao.DataAccessException;
-import org.springframework.jdbc.core.JdbcTemplate;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-
-@AllArgsConstructor
-public class BorrowingDatabaseAdapter implements BorrowingDatabase {
-
-    private JdbcTemplate jdbcTemplate;
-
-    @Override
-    public void setBookAvailable(Long bookId) {
-        jdbcTemplate.update(
-                "INSERT INTO available (book_id) VALUES (?)",
-                bookId);
-    }
-
-    @Override
-    public Optional<AvailableBook> getAvailableBook(Long bookId) {
-        try {
-            return Optional.ofNullable(
-                    jdbcTemplate.queryForObject(
-                    "SELECT book_id FROM available WHERE book_id = ?",
-                    AvailableBook.class,
-                            bookId));
-        } catch (DataAccessException exception) {
-            return Optional.empty();
-        }
-    }
-
-    @Override
-    public Optional<ActiveUser> getActiveUser(Long userId) {
-        try {
-            jdbcTemplate.queryForObject(
-                            "SELECT id FROM public.user as u WHERE u.id = ?",
-                            Long.class,
-                            userId);
-        } catch (DataAccessException exception) {
-            return Optional.empty();
-        }
-
-        List<ReservedBook> reservedBooksByUser = getReservedBooksByUser(userId);
-        return Optional.of(new ActiveUser(userId, reservedBooksByUser));
-    }
-
-    private List<ReservedBook> getReservedBooksByUser(Long userId) {
-        try {
-            return jdbcTemplate.queryForList(
-                    "SELECT book_id FROM reserved WHERE reserved.user_id = ?",
-                    ReservedBook.class,
-                    userId
-            );
-        } catch (DataAccessException exception){
-            return new ArrayList<>();
-        }
-    }
-
-    @Override
-    public ReservationDetails save(ReservedBook reservedBook) {
-       jdbcTemplate.update(
-               "INSERT INTO reserved (book_id, user_id) VALUES (?, ?)",
-               reservedBook.getIdAsLong(),
-               reservedBook.getAssignedUserIdAsLong());
-
-       ReservationId reservationId = jdbcTemplate.queryForObject(
-               "SELECT id FROM reserved WHERE book_id = ?",
-               ReservationId.class,
-               reservedBook.getIdAsLong());
-       return new ReservationDetails(reservationId, reservedBook);
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/model/ActiveUser.java

@@ -1,36 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.exception.TooManyBooksAssignedToUserException;
-import lombok.EqualsAndHashCode;
-
-import java.util.List;
-
-@EqualsAndHashCode
-public class ActiveUser {
-
-    private final Long id;
-    private final List<ReservedBook> reservedBooks;
-
-    public ActiveUser(Long id, List<ReservedBook> reservedBooks) {
-        this.id = id;
-        this.reservedBooks = reservedBooks;
-    }
-
-    public ReservedBook reserve(AvailableBook availableBook){
-        if (reservedBooks.size() < 3){
-            ReservedBook reservedBook = new ReservedBook(availableBook.getIdAsLong(), id);
-            reservedBooks.add(reservedBook);
-            return reservedBook;
-        } else {
-            throw new TooManyBooksAssignedToUserException(id);
-        }
-    }
-
-    public Long getIdAsLong(){
-        return id;
-    }
-
-    public List<ReservedBook> getReservedBookList(){
-        return reservedBooks;
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/model/Book.java

@@ -1,5 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
-
-interface Book {
-    Long getIdAsLong();
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/model/ReservedBook.java

@@ -1,24 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
-
-import lombok.EqualsAndHashCode;
-
-@EqualsAndHashCode
-public class ReservedBook implements Book {
-
-    private final Long bookId;
-    private final Long userId;
-
-    public ReservedBook(Long bookId, Long userId) {
-        this.bookId = bookId;
-        this.userId = userId;
-    }
-
-    @Override
-    public Long getIdAsLong() {
-        return bookId;
-    }
-
-    public Long getAssignedUserIdAsLong(){
-        return userId;
-    }
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/ports/incoming/MakeBookAvailable.java

@@ -1,7 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.ports.incoming;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.MakeBookAvailableCommand;
-
-public interface MakeBookAvailable {
-    void handle(MakeBookAvailableCommand bookAvailableCommand);
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/ports/incoming/ReserveBook.java

@@ -1,7 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.ports.incoming;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.BookReservationCommand;
-
-public interface ReserveBook {
-    Long handle(BookReservationCommand bookReservation);
-}

src/main/java/io/wkrzywiec/hexagonal/library/borrowing/ports/outgoing/BorrowingDatabase.java

@@ -1,15 +0,0 @@
-package io.wkrzywiec.hexagonal.library.borrowing.ports.outgoing;
-
-import io.wkrzywiec.hexagonal.library.borrowing.model.ActiveUser;
-import io.wkrzywiec.hexagonal.library.borrowing.model.AvailableBook;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservationDetails;
-import io.wkrzywiec.hexagonal.library.borrowing.model.ReservedBook;
-
-import java.util.Optional;
-
-public interface BorrowingDatabase {
-    void setBookAvailable(Long bookId);
-    Optional<AvailableBook> getAvailableBook(Long bookId);
-    Optional<ActiveUser> getActiveUser(Long userId);
-    ReservationDetails save(ReservedBook reservedBook);
-}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/application/BorrowingDomainController.java

@@ -0,0 +1,50 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.application;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.application.model.ChangeBookStatusRequest;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservationCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.GiveBackBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.BorrowBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.GiveBackBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.ReserveBook;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/books")
+@RequiredArgsConstructor
+public class BorrowingDomainController {
+
+    @Qualifier("GiveBackBook")
+    private final GiveBackBook giveBackBook;
+
+    @Qualifier("ReserveBook")
+    private final ReserveBook reserveBook;
+
+    @Qualifier("BorrowBook")
+    private final BorrowBook borrowBook;
+
+    @PatchMapping("/{id}/status")
+    public ResponseEntity<String> borrowBook(@PathVariable("id") Long bookId, @RequestBody ChangeBookStatusRequest request){
+        switch (request.getStatus()){
+            case AVAILABLE:
+                giveBackBook.handle(new GiveBackBookCommand(bookId, request.getUserId()));
+                return new ResponseEntity<>("Book with an id " + bookId + " was returned", HttpStatus.OK);
+            case RESERVED:
+                Long reservationId = reserveBook.handle(new BookReservationCommand(bookId, request.getUserId()));
+                return new ResponseEntity<>("Reservation has been made with an id " + reservationId, HttpStatus.OK);
+            case BORROWED:
+                borrowBook.handle(new BorrowBookCommand(bookId, request.getUserId()));
+                return new ResponseEntity<>("Book with an id " + bookId + " was borrowed", HttpStatus.OK);
+            default:
+                return new ResponseEntity<>("Book can't have status: " + request.getStatus(), HttpStatus.BAD_REQUEST);
+        }
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/application/NewBookWasAddedEventHandler.java

@@ -1,9 +1,10 @@
-package io.wkrzywiec.hexagonal.library.borrowing.application;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.application;
 
-import io.wkrzywiec.hexagonal.library.borrowing.model.MakeBookAvailableCommand;
-import io.wkrzywiec.hexagonal.library.borrowing.ports.incoming.MakeBookAvailable;
-import io.wkrzywiec.hexagonal.library.inventory.model.NewBookWasAddedEvent;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.MakeBookAvailableCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.MakeBookAvailable;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.NewBookWasAddedEvent;
 import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.event.EventListener;
 import org.springframework.stereotype.Component;
 
@@ -11,6 +12,7 @@ import org.springframework.stereotype.Component;
 @Component
 public class NewBookWasAddedEventHandler {
 
+    @Qualifier("MakeBookAvailable")
     private final MakeBookAvailable makeBookAvailable;
 
     @EventListener

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/application/OverdueReservationScheduler.java

@@ -0,0 +1,18 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.application;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.CancelOverdueReservations;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.scheduling.annotation.Scheduled;
+
+@RequiredArgsConstructor
+public class OverdueReservationScheduler {
+
+    @Qualifier("CancelOverdueReservations")
+    private final CancelOverdueReservations overdueReservations;
+
+    @Scheduled(fixedRate = 60 * 1000)
+    public void checkOverdueReservations(){
+        overdueReservations.cancelOverdueReservations();
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/application/model/BookStatus.java

@@ -0,0 +1,5 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.application.model;
+
+public enum BookStatus {
+    AVAILABLE, RESERVED, BORROWED
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/application/model/ChangeBookStatusRequest.java

@@ -0,0 +1,12 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.application.model;
+
+import lombok.Builder;
+import lombok.Data;
+
+@Data
+@Builder
+public class ChangeBookStatusRequest {
+
+    private BookStatus status;
+    private Long userId;
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/BorrowingFacade.java

@@ -0,0 +1,91 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ActiveUser;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.AvailableBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservationCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservedEvent;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowedBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.GiveBackBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.MakeBookAvailableCommand;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.OverdueReservation;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservationDetails;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservedBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception.ActiveUserNotFoundException;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception.AvailableBookNotFoundExeption;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception.BorrowedBookNotFoundException;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception.ReservedBookNotFoundException;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.BorrowBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.CancelOverdueReservations;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.GiveBackBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.MakeBookAvailable;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming.ReserveBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing.BorrowingDatabase;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing.BorrowingEventPublisher;
+
+import java.util.List;
+
+public class BorrowingFacade implements MakeBookAvailable, ReserveBook, CancelOverdueReservations, BorrowBook, GiveBackBook {
+
+    private final BorrowingDatabase database;
+    private final BorrowingEventPublisher eventPublisher;
+
+    public BorrowingFacade(BorrowingDatabase database, BorrowingEventPublisher eventPublisher) {
+        this.database = database;
+        this.eventPublisher = eventPublisher;
+    }
+
+    @Override
+    public void handle(MakeBookAvailableCommand bookAvailableCommand) {
+        database.save(new AvailableBook(bookAvailableCommand.getBookId()));
+    }
+
+    @Override
+    public Long handle(BookReservationCommand bookReservation) {
+        AvailableBook availableBook =
+                database.getAvailableBook(bookReservation.getBookId())
+                .orElseThrow(() -> new AvailableBookNotFoundExeption(bookReservation.getBookId()));
+
+        ActiveUser activeUser =
+                database.getActiveUser(bookReservation.getUserId())
+                .orElseThrow(() -> new ActiveUserNotFoundException(bookReservation.getUserId()));
+
+        ReservedBook reservedBook = activeUser.reserve(availableBook);
+        ReservationDetails reservationDetails = database.save(reservedBook);
+        eventPublisher.publish(new BookReservedEvent(reservationDetails));
+        return reservationDetails.getReservationId().getIdAsLong();
+    }
+
+    @Override
+    public void cancelOverdueReservations() {
+        List<OverdueReservation> overdueReservationList = database.findReservationsForMoreThan(3L);
+        overdueReservationList.forEach(
+                overdueBook -> database.save(new AvailableBook(overdueBook.getBookIdentificationAsLong())));
+    }
+
+    @Override
+    public void handle(BorrowBookCommand borrowBookCommand) {
+        ActiveUser activeUser =
+                database.getActiveUser(borrowBookCommand.getUserId())
+                        .orElseThrow(() -> new ActiveUserNotFoundException(borrowBookCommand.getUserId()));
+        ReservedBook reservedBook =
+                database.getReservedBook(borrowBookCommand.getBookId())
+                .orElseThrow(() -> new ReservedBookNotFoundException(borrowBookCommand.getBookId()));
+
+        BorrowedBook borrowedBook = activeUser.borrow(reservedBook);
+        database.save(borrowedBook);
+    }
+
+    @Override
+    public void handle(GiveBackBookCommand command) {
+        BorrowedBook borrowedBook =
+                database.getBorrowedBook(command.getBookId())
+                .orElseThrow(() -> new BorrowedBookNotFoundException(command.getBookId()));
+        ActiveUser activeUser =
+                database.getActiveUser(command.getUserId())
+                        .orElseThrow(() -> new ActiveUserNotFoundException(command.getUserId()));
+
+        AvailableBook availableBook = activeUser.giveBack(borrowedBook);
+        database.save(availableBook);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/ActiveUser.java

@@ -0,0 +1,69 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception.TooManyBooksAssignedToUserException;
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+
+@EqualsAndHashCode
+@ToString
+public class ActiveUser {
+
+    private final Long id;
+    private final List<ReservedBook> reservedBooks;
+    private final List<BorrowedBook> borrowedBooks;
+
+    public ActiveUser(Long id, List<ReservedBook> reservedBooks, List<BorrowedBook> borrowedBooks) {
+        this.id = id;
+        this.reservedBooks = reservedBooks;
+        this.borrowedBooks = borrowedBooks;
+    }
+
+    public ReservedBook reserve(AvailableBook availableBook){
+        if (hasUserNotReachedLimitOfBooks()){
+            ReservedBook reservedBook = new ReservedBook(availableBook.getIdAsLong(), id);
+            reservedBooks.add(reservedBook);
+            return reservedBook;
+        } else {
+            throw new TooManyBooksAssignedToUserException(id);
+        }
+    }
+
+    public BorrowedBook borrow(ReservedBook reservedBook) {
+        if (hasUserNotReachedLimitOfBooks()){
+            BorrowedBook borrowedBook = new BorrowedBook(reservedBook.getIdAsLong(), id);
+            borrowedBooks.add(borrowedBook);
+            return borrowedBook;
+        } else {
+            throw new TooManyBooksAssignedToUserException(id);
+        }
+    }
+
+    public AvailableBook giveBack(BorrowedBook borrowedBook) {
+        boolean isBookRemovedFromUserAccount = borrowedBooks.removeIf(book -> book.equals(borrowedBook));
+        if (isBookRemovedFromUserAccount){
+            return new AvailableBook(borrowedBook.getIdAsLong());
+        } else {
+            throw new IllegalArgumentException("User with an id: " + id + " didn't borrow book with an id: " + borrowedBook.getIdAsLong());
+        }
+    }
+
+    public Long getIdAsLong(){
+        return id;
+    }
+
+    public List<ReservedBook> getReservedBookList(){
+        return reservedBooks;
+    }
+
+    public List<BorrowedBook> getBorrowedBookList() {
+        return borrowedBooks;
+    }
+
+    private boolean hasUserNotReachedLimitOfBooks(){
+        return reservedBooks.size() + borrowedBooks.size() < 3;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/AvailableBook.java

@@ -1,8 +1,10 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
 
 import lombok.EqualsAndHashCode;
+import lombok.ToString;
 
 @EqualsAndHashCode
+@ToString
 public class AvailableBook implements Book {
 
     private final Long id;

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/Book.java

@@ -0,0 +1,5 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+interface Book {
+    Long getIdAsLong();
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/BookReservationCommand.java

@@ -1,10 +1,12 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
 
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Getter;
+import lombok.NoArgsConstructor;
 
 @AllArgsConstructor
+@NoArgsConstructor
 @Getter
 @Builder
 public class BookReservationCommand {

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/BookReservedEvent.java

@@ -0,0 +1,35 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import java.time.Instant;
+
+public class BookReservedEvent {
+
+    private final ReservationId reservationId;
+    private final Long userId;
+    private final ReservedBook reservedBook;
+    private final Instant timestamp;
+
+    public BookReservedEvent(ReservationDetails reservationDetails) {
+        this.reservationId = reservationDetails.getReservationId();
+        this.userId = reservationDetails.getReservedBook().getAssignedUserIdAsLong();
+        this.reservedBook = reservationDetails.getReservedBook();
+        timestamp = Instant.now();
+    }
+
+    public Long getReservationIdAsLong() {
+        return reservationId.getIdAsLong();
+    }
+
+    public Long getUserIdAsLong() {
+        return userId;
+    }
+
+    public Long getBookIdAsLong() {
+        return reservedBook.getIdAsLong();
+    }
+
+    public String getEventTimeStampAsString() {
+        return timestamp.toString();
+    }
+
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/BorrowBookCommand.java

@@ -0,0 +1,13 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+
+@AllArgsConstructor
+@Getter
+@Builder
+public class BorrowBookCommand {
+    private Long bookId;
+    private Long userId;
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/BorrowedBook.java

@@ -0,0 +1,39 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.EqualsAndHashCode;
+
+import java.time.Instant;
+
+@EqualsAndHashCode
+public class BorrowedBook implements Book {
+
+    private Long bookId;
+    private Long userId;
+    @EqualsAndHashCode.Exclude
+    private Instant borrowedDate;
+
+    public BorrowedBook(Long bookId, Long userId) {
+        this.bookId = bookId;
+        this.userId = userId;
+        this.borrowedDate = Instant.now();
+    }
+
+    public BorrowedBook(Long bookId, Long userId, Instant borrowedDate) {
+        this.bookId = bookId;
+        this.userId = userId;
+        this.borrowedDate = borrowedDate;
+    }
+
+    @Override
+    public Long getIdAsLong() {
+        return bookId;
+    }
+
+    public Long getAssignedUserIdAsLong(){
+        return userId;
+    }
+
+    public Instant getBorrowedDateAsInstant(){
+        return borrowedDate;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/DueDate.java

@@ -0,0 +1,14 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.AllArgsConstructor;
+
+import java.time.Instant;
+
+@AllArgsConstructor
+public class DueDate {
+    private final Instant timeStamp;
+
+    public Instant asInstant(){
+        return timeStamp;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/GiveBackBookCommand.java

@@ -0,0 +1,13 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+
+@AllArgsConstructor
+@Getter
+@Builder
+public class GiveBackBookCommand {
+    private Long bookId;
+    private Long userId;
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/MakeBookAvailableCommand.java

@@ -1,10 +1,8 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
 
 import lombok.AllArgsConstructor;
 import lombok.Builder;
-import lombok.Data;
 import lombok.Getter;
-import lombok.NoArgsConstructor;
 
 @AllArgsConstructor
 @Getter

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/OverdueReservation.java

@@ -0,0 +1,13 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.AllArgsConstructor;
+
+@AllArgsConstructor
+public class OverdueReservation {
+    private Long reservationId;
+    private Long bookIdentification;
+
+    public Long getBookIdentificationAsLong() {
+        return bookIdentification;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/ReservationDetails.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
 
 import lombok.EqualsAndHashCode;
 import lombok.Getter;

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/ReservationId.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
 
 import lombok.EqualsAndHashCode;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/ReservedBook.java

@@ -0,0 +1,39 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model;
+
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+
+import java.time.Instant;
+
+@EqualsAndHashCode
+public class ReservedBook implements Book {
+
+    private final Long bookId;
+    private final Long userId;
+    private final Instant reservedDate;
+
+    public ReservedBook(Long bookId, Long userId) {
+        this.bookId = bookId;
+        this.userId = userId;
+        this.reservedDate = Instant.now();
+    }
+
+    public ReservedBook(Long bookId, Long userId, Instant reservedDate) {
+        this.bookId = bookId;
+        this.userId = userId;
+        this.reservedDate = reservedDate;
+    }
+
+    @Override
+    public Long getIdAsLong() {
+        return bookId;
+    }
+
+    public Long getAssignedUserIdAsLong(){
+        return userId;
+    }
+
+    public Instant getReservedDateAsInstant(){
+        return reservedDate;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/exception/ActiveUserNotFoundException.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model.exception;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception;
 
 public class ActiveUserNotFoundException extends RuntimeException {
     public ActiveUserNotFoundException(Long bookId){

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/exception/AvailableBookNotFoundExeption.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model.exception;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception;
 
 public class AvailableBookNotFoundExeption extends RuntimeException {
     public AvailableBookNotFoundExeption(Long bookId){

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/exception/BorrowedBookNotFoundException.java

@@ -0,0 +1,10 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception;
+
+public class BorrowedBookNotFoundException extends RuntimeException {
+    public BorrowedBookNotFoundException(Long bookId) {
+        super("There is no borrowed book with an ID: " + bookId,
+                null,
+                false,
+                false);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/exception/ReservedBookNotFoundException.java

@@ -0,0 +1,10 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception;
+
+public class ReservedBookNotFoundException extends RuntimeException {
+    public ReservedBookNotFoundException(Long bookId) {
+        super("There is no reserved book with an ID: " + bookId,
+                null,
+                false,
+                false);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/model/exception/TooManyBooksAssignedToUserException.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.borrowing.model.exception;
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.exception;
 
 public class TooManyBooksAssignedToUserException extends RuntimeException {
     public TooManyBooksAssignedToUserException(Long userId){

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/incoming/BorrowBook.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowBookCommand;
+
+public interface BorrowBook {
+    void handle(BorrowBookCommand borrowBookCommand);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/incoming/CancelOverdueReservations.java

@@ -0,0 +1,5 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming;
+
+public interface CancelOverdueReservations {
+    void cancelOverdueReservations();
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/incoming/GiveBackBook.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.GiveBackBookCommand;
+
+public interface GiveBackBook {
+    void handle(GiveBackBookCommand command);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/incoming/MakeBookAvailable.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.MakeBookAvailableCommand;
+
+public interface MakeBookAvailable {
+    void handle(MakeBookAvailableCommand bookAvailableCommand);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/incoming/ReserveBook.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservationCommand;
+
+public interface ReserveBook {
+    Long handle(BookReservationCommand bookReservation);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/outgoing/BorrowingDatabase.java

@@ -0,0 +1,23 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ActiveUser;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.AvailableBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowedBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.DueDate;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.OverdueReservation;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservationDetails;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservedBook;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface BorrowingDatabase {
+    void save(AvailableBook availableBook);
+    ReservationDetails save(ReservedBook reservedBook);
+    void save(BorrowedBook borrowedBook);
+    Optional<AvailableBook> getAvailableBook(Long bookId);
+    Optional<ActiveUser> getActiveUser(Long userId);
+    List<OverdueReservation> findReservationsForMoreThan(Long days);
+    Optional<ReservedBook> getReservedBook(Long bookId);
+    Optional<BorrowedBook> getBorrowedBook(Long bookId);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/core/ports/outgoing/BorrowingEventPublisher.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservedEvent;
+
+public interface BorrowingEventPublisher {
+    public void publish(BookReservedEvent event);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/infrastructure/BorrowingDatabaseAdapter.java

@@ -0,0 +1,172 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowedBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.entity.OverdueReservationEntity;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ActiveUser;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.AvailableBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.DueDate;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.OverdueReservation;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservationDetails;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservationId;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservedBook;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing.BorrowingDatabase;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.mapper.BorrowedBookRowMapper;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.mapper.ReservedBookRowMapper;
+import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.core.BeanPropertyRowMapper;
+import org.springframework.jdbc.core.JdbcTemplate;
+
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+@RequiredArgsConstructor
+public class BorrowingDatabaseAdapter implements BorrowingDatabase {
+
+    private final JdbcTemplate jdbcTemplate;
+
+    @Override
+    public void save(AvailableBook availableBook) {
+        jdbcTemplate.update(
+                "INSERT INTO available (book_id) VALUES (?)",
+                availableBook.getIdAsLong());
+
+        jdbcTemplate.update(
+                "DELETE FROM reserved WHERE book_id = ?",
+                availableBook.getIdAsLong());
+
+        jdbcTemplate.update(
+                "DELETE FROM borrowed WHERE book_id = ?",
+                availableBook.getIdAsLong());
+    }
+
+    @Override
+    public Optional<AvailableBook> getAvailableBook(Long bookId) {
+        try {
+            return Optional.ofNullable(
+                    jdbcTemplate.queryForObject(
+                    "SELECT book_id FROM available WHERE book_id = ?",
+                    AvailableBook.class,
+                            bookId));
+        } catch (DataAccessException exception) {
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public Optional<ActiveUser> getActiveUser(Long userId) {
+        try {
+            jdbcTemplate.queryForObject(
+                            "SELECT id FROM public.library_user as u WHERE u.id = ?",
+                            Long.class,
+                            userId);
+        } catch (DataAccessException exception) {
+            return Optional.empty();
+        }
+
+        List<ReservedBook> reservedBooksByUser = getReservedBooksByUser(userId);
+        List<BorrowedBook> borrowedBooksByUser = getBorrowedBooksByUser(userId);
+        return Optional.of(new ActiveUser(userId, reservedBooksByUser, borrowedBooksByUser));
+    }
+
+    @Override
+    public ReservationDetails save(ReservedBook reservedBook) {
+       jdbcTemplate.update(
+               "INSERT INTO reserved (book_id, user_id, reserved_date) VALUES (?, ?, ?)",
+               reservedBook.getIdAsLong(),
+               reservedBook.getAssignedUserIdAsLong(),
+               Timestamp.from(reservedBook.getReservedDateAsInstant()));
+
+        jdbcTemplate.update(
+                "DELETE FROM available WHERE book_id = ?",
+                reservedBook.getIdAsLong());
+
+       ReservationId reservationId = jdbcTemplate.queryForObject(
+               "SELECT id FROM reserved WHERE book_id = ?",
+               ReservationId.class,
+               reservedBook.getIdAsLong());
+       return new ReservationDetails(reservationId, reservedBook);
+    }
+
+    @Override
+    public void save(BorrowedBook borrowedBook) {
+        jdbcTemplate.update(
+                "INSERT INTO borrowed (book_id, user_id, borrowed_date) VALUES (?, ?, ?)",
+                borrowedBook.getIdAsLong(),
+                borrowedBook.getAssignedUserIdAsLong(),
+                Timestamp.from(borrowedBook.getBorrowedDateAsInstant()));
+
+        jdbcTemplate.update(
+                "DELETE FROM reserved WHERE book_id = ?",
+                borrowedBook.getIdAsLong());
+
+        jdbcTemplate.update(
+                "DELETE FROM available WHERE book_id = ?",
+                borrowedBook.getIdAsLong());
+
+    }
+
+    @Override
+    public List<OverdueReservation> findReservationsForMoreThan(Long days) {
+        List<OverdueReservationEntity> entities = jdbcTemplate.query(
+                "SELECT id AS reservationId, book_id AS bookIdentification FROM reserved WHERE DATEADD(day, ?, reserved_date) > NOW()",
+                new BeanPropertyRowMapper<OverdueReservationEntity>(OverdueReservationEntity.class),
+               days);
+        return entities.stream()
+                .map(entity -> new OverdueReservation(entity.getReservationId(), entity.getBookIdentification()))
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public Optional<ReservedBook> getReservedBook(Long bookId) {
+        try {
+            return Optional.ofNullable(
+                    jdbcTemplate.queryForObject(
+                            "SELECT book_id, user_id, reserved_date FROM reserved WHERE book_id = ?",
+                            new ReservedBookRowMapper(),
+                            bookId));
+        } catch (DataAccessException exception) {
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public Optional<BorrowedBook> getBorrowedBook(Long bookId) {
+        try {
+            return Optional.ofNullable(
+                    jdbcTemplate.queryForObject(
+                            "SELECT book_id, user_id, borrowed_date FROM borrowed WHERE book_id = ?",
+                            new BorrowedBookRowMapper(),
+                            bookId));
+        } catch (DataAccessException exception) {
+            return Optional.empty();
+        }
+    }
+
+    private List<ReservedBook> getReservedBooksByUser(Long userId) {
+        try {
+            return jdbcTemplate.query(
+                    "SELECT book_id, user_id, reserved_date FROM reserved WHERE user_id = ?",
+                    new ReservedBookRowMapper(),
+                    userId
+            );
+        } catch (DataAccessException exception){
+            return new ArrayList<>();
+        }
+    }
+
+    private List<BorrowedBook> getBorrowedBooksByUser(Long userId) {
+        try {
+            return jdbcTemplate.query(
+                    "SELECT book_id, user_id, borrowed_date FROM borrowed WHERE user_id = ?",
+                    new BorrowedBookRowMapper(),
+                    userId
+            );
+        } catch (DataAccessException exception){
+            return new ArrayList<>();
+        }
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/infrastructure/SpringBorrowingEventPublisherAdapter.java

@@ -0,0 +1,19 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservedEvent;
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.ports.outgoing.BorrowingEventPublisher;
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.stereotype.Component;
+
+@Component
+@RequiredArgsConstructor
+public class SpringBorrowingEventPublisherAdapter implements BorrowingEventPublisher {
+
+    private final ApplicationEventPublisher eventPublisher;
+
+    @Override
+    public void publish(BookReservedEvent event) {
+        eventPublisher.publishEvent(event);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/infrastructure/entity/OverdueReservationEntity.java

@@ -0,0 +1,9 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.entity;
+
+import lombok.Data;
+
+@Data
+public class OverdueReservationEntity {
+    private Long reservationId;
+    private Long bookIdentification;
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/infrastructure/mapper/BorrowedBookRowMapper.java

@@ -0,0 +1,20 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.mapper;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BorrowedBook;
+import org.springframework.jdbc.core.RowMapper;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+
+public class BorrowedBookRowMapper implements RowMapper<BorrowedBook> {
+
+    @Override
+    public BorrowedBook mapRow(ResultSet rs, int rowNum) throws SQLException {
+        return new BorrowedBook(
+                rs.getLong("book_id"),
+                rs.getLong("user_id"),
+                rs.getTimestamp("borrowed_date").toInstant()
+        );
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/borrowing/infrastructure/mapper/ReservedBookRowMapper.java

@@ -0,0 +1,19 @@
+package io.wkrzywiec.hexagonal.library.domain.borrowing.infrastructure.mapper;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.ReservedBook;
+import org.springframework.jdbc.core.RowMapper;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public class ReservedBookRowMapper implements RowMapper<ReservedBook> {
+
+    @Override
+    public ReservedBook mapRow(ResultSet rs, int rowNum) throws SQLException {
+        return new ReservedBook(
+                rs.getLong("book_id"),
+                rs.getLong("user_id"),
+                rs.getTimestamp("reserved_date").toInstant()
+        );
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/application/BookReservedEventHandler.java

@@ -0,0 +1,24 @@
+package io.wkrzywiec.hexagonal.library.domain.email.application;
+
+import io.wkrzywiec.hexagonal.library.domain.borrowing.core.model.BookReservedEvent;
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.SendReservationConfirmationCommand;
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.incoming.SendReservationConfirmation;
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+@Component
+@RequiredArgsConstructor
+public class BookReservedEventHandler {
+
+    private final SendReservationConfirmation sendReservationConfirmation;
+
+    @EventListener
+    public void handle(BookReservedEvent event) {
+        sendReservationConfirmation.handle(
+                new SendReservationConfirmationCommand(
+                        event.getReservationIdAsLong(),
+                        event.getUserIdAsLong(),
+                        event.getBookIdAsLong()));
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/EmailCreator.java

@@ -0,0 +1,18 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core;
+
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.EmailAddress;
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.ReservationConfirmEmail;
+
+class EmailCreator {
+
+    static ReservationConfirmEmail reservationEmail(Long reservationId, String bookTitle, String emailTo){
+
+        EmailAddress from = new EmailAddress("tom@library.com");
+        EmailAddress to = new EmailAddress(emailTo);
+
+        String subject = String.format("Library - book reservation confirmation (id - %d)", reservationId);
+        String content = String.format("Dear reader,%n you have reserved a %s book which will be waiting for you in our library for next 2 days. Your reservation id is %d. %n Have a nice day, %n Library",
+                bookTitle, reservationId);
+        return new ReservationConfirmEmail(from, to, subject, content);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/EmailFacade.java

@@ -0,0 +1,32 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core;
+
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.ReservationConfirmEmail;
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.SendReservationConfirmationCommand;
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.incoming.SendReservationConfirmation;
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing.EmailSender;
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing.EmailDatabase;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class EmailFacade implements SendReservationConfirmation {
+
+    private final EmailSender emailSender;
+    private final EmailDatabase database;
+
+    @Override
+    public void handle(SendReservationConfirmationCommand sendReservationConfirmation) {
+        String bookTitle = database
+                .getTitleByBookId(sendReservationConfirmation.getBookId())
+                .orElseThrow(() -> new IllegalArgumentException("Can't get book title from database. Reason: there is no book with an id: " + sendReservationConfirmation.getBookId()));
+        String userEmailAddress = database
+                .getUserEmailAddress(sendReservationConfirmation.getUserId())
+                .orElseThrow(() -> new IllegalArgumentException("Can't get email address from database. Reason: there is no user with an id: " + sendReservationConfirmation.getUserId()));
+
+        ReservationConfirmEmail reservationConfirmEmail = EmailCreator.reservationEmail(
+                sendReservationConfirmation.getReservationId(),
+                bookTitle,
+                userEmailAddress
+        );
+        emailSender.sendReservationConfirmationEmail(reservationConfirmEmail);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/model/EmailAddress.java

@@ -0,0 +1,24 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.model;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class EmailAddress {
+
+    private final String value;
+
+    public EmailAddress(String value) {
+        Pattern pattern = Pattern.compile("^(.+)@(.+)$");
+        Matcher matcher = pattern.matcher(value);
+        if(matcher.matches()){
+            this.value = value;
+        } else {
+            throw new IllegalArgumentException("Provided value is not an email address");
+        }
+
+    }
+
+    public String getAsString() {
+        return value;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/model/ReservationConfirmEmail.java

@@ -0,0 +1,28 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.model;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class ReservationConfirmEmail {
+
+    private final EmailAddress from;
+    private final EmailAddress to;
+    private final String subject;
+    private final String content;
+
+    public String getFromEmailAddressAsString(){
+        return this.from.getAsString();
+    }
+
+    public String getToEmailAddressAsString(){
+        return this.to.getAsString();
+    }
+
+    public String getSubjectAsString(){
+        return this.subject;
+    }
+
+    public String getContentAsString(){
+        return this.content;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/model/SendReservationConfirmationCommand.java

@@ -0,0 +1,17 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.model;
+
+import lombok.Getter;
+
+@Getter
+public class SendReservationConfirmationCommand {
+
+    private final Long reservationId;
+    private final Long userId;
+    private final Long bookId;
+
+    public SendReservationConfirmationCommand(Long reservationId, Long userId, Long bookId) {
+        this.reservationId = reservationId;
+        this.userId = userId;
+        this.bookId = bookId;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/ports/incoming/SendReservationConfirmation.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.SendReservationConfirmationCommand;
+
+public interface SendReservationConfirmation {
+    void handle(SendReservationConfirmationCommand reservationConfirmationCommand);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/ports/outgoing/EmailDatabase.java

@@ -0,0 +1,8 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing;
+
+import java.util.Optional;
+
+public interface EmailDatabase {
+    Optional<String> getTitleByBookId(Long bookId);
+    Optional<String> getUserEmailAddress(Long userId);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/core/ports/outgoing/EmailSender.java

@@ -0,0 +1,8 @@
+package io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing;
+
+
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.ReservationConfirmEmail;
+
+public interface EmailSender {
+    void sendReservationConfirmationEmail(ReservationConfirmEmail reservationConfirmEmail);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/infrastructure/EmailDatabaseAdapter.java

@@ -0,0 +1,38 @@
+package io.wkrzywiec.hexagonal.library.domain.email.infrastructure;
+
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing.EmailDatabase;
+import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.core.JdbcTemplate;
+
+import java.util.Optional;
+
+@RequiredArgsConstructor
+public class EmailDatabaseAdapter implements EmailDatabase {
+
+    private final JdbcTemplate jdbcTemplate;
+
+    @Override
+    public Optional<String> getTitleByBookId(Long bookId) {
+        try {
+            return Optional.ofNullable(jdbcTemplate.queryForObject(
+                    "SELECT title FROM book WHERE id = ?",
+                    String.class,
+                    bookId));
+        } catch (DataAccessException ex){
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public Optional<String> getUserEmailAddress(Long userId) {
+        try {
+            return Optional.ofNullable(jdbcTemplate.queryForObject(
+                    "SELECT email FROM library_user WHERE id = ?",
+                    String.class,
+                    userId));
+        } catch (DataAccessException ex){
+            return Optional.empty();
+        }
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/email/infrastructure/SendGridEmailSender.java

@@ -0,0 +1,38 @@
+package io.wkrzywiec.hexagonal.library.domain.email.infrastructure;
+
+import com.sendgrid.Method;
+import com.sendgrid.Request;
+import com.sendgrid.SendGrid;
+import com.sendgrid.helpers.mail.Mail;
+import com.sendgrid.helpers.mail.objects.Content;
+import com.sendgrid.helpers.mail.objects.Email;
+import io.wkrzywiec.hexagonal.library.domain.email.core.model.ReservationConfirmEmail;
+import io.wkrzywiec.hexagonal.library.domain.email.core.ports.outgoing.EmailSender;
+
+import java.io.IOException;
+
+public class SendGridEmailSender implements EmailSender {
+
+    @Override
+    public void sendReservationConfirmationEmail(ReservationConfirmEmail reservationConfirmEmail) {
+        Email from = new Email(reservationConfirmEmail.getFromEmailAddressAsString());
+        Email to = new Email(reservationConfirmEmail.getToEmailAddressAsString());
+        Content content = new Content("text/plain", reservationConfirmEmail.getContentAsString());
+        Mail mail = new Mail(
+                from,
+                reservationConfirmEmail.getSubjectAsString(),
+                to,
+                content);
+
+        SendGrid sg = new SendGrid(System.getenv("SENDGRID_API_KEY"));
+        Request request = new Request();
+        try {
+            request.setMethod(Method.POST);
+            request.setEndpoint("mail/send");
+            request.setBody(mail.build());
+            sg.api(request);
+        } catch (IOException ex) {
+            System.out.print(ex);
+        }
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/application/BookCommandController.java

@@ -1,7 +1,7 @@
-package io.wkrzywiec.hexagonal.library.inventory.application;
+package io.wkrzywiec.hexagonal.library.domain.inventory.application;
 
-import io.wkrzywiec.hexagonal.library.inventory.model.AddNewBookCommand;
-import io.wkrzywiec.hexagonal.library.inventory.ports.incoming.AddNewBook;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.AddNewBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.incoming.AddNewBook;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/InventoryFacade.java

@@ -1,12 +1,12 @@
-package io.wkrzywiec.hexagonal.library.inventory;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core;
 
-import io.wkrzywiec.hexagonal.library.inventory.model.AddNewBookCommand;
-import io.wkrzywiec.hexagonal.library.inventory.model.Book;
-import io.wkrzywiec.hexagonal.library.inventory.model.NewBookWasAddedEvent;
-import io.wkrzywiec.hexagonal.library.inventory.ports.incoming.AddNewBook;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.InventoryEventPublisher;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.GetBookDetails;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.InventoryDatabase;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.AddNewBookCommand;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.NewBookWasAddedEvent;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.incoming.AddNewBook;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.InventoryEventPublisher;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.GetBookDetails;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.InventoryDatabase;
 
 
 public class InventoryFacade implements AddNewBook{

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/AddNewBookCommand.java

@@ -1,8 +1,7 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.AllArgsConstructor;
 import lombok.Builder;
-import lombok.Data;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/Author.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.EqualsAndHashCode;
 import lombok.ToString;

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/Book.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.EqualsAndHashCode;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/BookIdentification.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.EqualsAndHashCode;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/Isbn10.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.EqualsAndHashCode;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/Isbn13.java

@@ -1,7 +1,6 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import lombok.EqualsAndHashCode;
-import lombok.ToString;
 
 import javax.persistence.Column;
 import javax.persistence.Embeddable;

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/model/NewBookWasAddedEvent.java

@@ -1,4 +1,4 @@
-package io.wkrzywiec.hexagonal.library.inventory.model;
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.model;
 
 import java.time.Instant;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/ports/incoming/AddNewBook.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.AddNewBookCommand;
+
+public interface AddNewBook {
+    void handle(AddNewBookCommand addNewBookCommand);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/ports/outgoing/GetBookDetails.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
+
+public interface GetBookDetails {
+    Book handle(String bookId);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/ports/outgoing/InventoryDatabase.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
+
+public interface InventoryDatabase {
+    Book save(Book book);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/core/ports/outgoing/InventoryEventPublisher.java

@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.NewBookWasAddedEvent;
+
+public interface InventoryEventPublisher {
+    void publishNewBookWasAddedEvent(NewBookWasAddedEvent event);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/infrastructure/BookRepository.java

@@ -1,6 +1,6 @@
-package io.wkrzywiec.hexagonal.library.inventory.infrastructure;
+package io.wkrzywiec.hexagonal.library.domain.inventory.infrastructure;
 
-import io.wkrzywiec.hexagonal.library.inventory.model.Book;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.stereotype.Repository;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/infrastructure/GoogleBooksAdapter.java

@@ -1,14 +1,14 @@
-package io.wkrzywiec.hexagonal.library.inventory.infrastructure;
+package io.wkrzywiec.hexagonal.library.domain.inventory.infrastructure;
 
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
-import io.wkrzywiec.hexagonal.library.inventory.model.Author;
-import io.wkrzywiec.hexagonal.library.inventory.model.Book;
-import io.wkrzywiec.hexagonal.library.inventory.model.BookIdentification;
-import io.wkrzywiec.hexagonal.library.inventory.model.Isbn10;
-import io.wkrzywiec.hexagonal.library.inventory.model.Isbn13;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.GetBookDetails;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Author;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.BookIdentification;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Isbn10;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Isbn13;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.GetBookDetails;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/infrastructure/InventoryDatabaseAdapter.java

@@ -1,7 +1,7 @@
-package io.wkrzywiec.hexagonal.library.inventory.infrastructure;
+package io.wkrzywiec.hexagonal.library.domain.inventory.infrastructure;
 
-import io.wkrzywiec.hexagonal.library.inventory.model.Book;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.InventoryDatabase;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.Book;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.InventoryDatabase;
 import lombok.RequiredArgsConstructor;
 
 @RequiredArgsConstructor

src/main/java/io/wkrzywiec/hexagonal/library/domain/inventory/infrastructure/SpringInventoryEventPublisherAdapter.java

@@ -1,7 +1,7 @@
-package io.wkrzywiec.hexagonal.library.inventory.infrastructure;
+package io.wkrzywiec.hexagonal.library.domain.inventory.infrastructure;
 
-import io.wkrzywiec.hexagonal.library.inventory.model.NewBookWasAddedEvent;
-import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.InventoryEventPublisher;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.model.NewBookWasAddedEvent;
+import io.wkrzywiec.hexagonal.library.domain.inventory.core.ports.outgoing.InventoryEventPublisher;
 import lombok.RequiredArgsConstructor;
 import org.springframework.context.ApplicationEventPublisher;
 

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/application/UserCommandController.java

@@ -0,0 +1,25 @@
+package io.wkrzywiec.hexagonal.library.domain.user.application;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.AddUserCommand;
+import io.wkrzywiec.hexagonal.library.domain.user.core.ports.incoming.AddNewUser;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/users")
+@RequiredArgsConstructor
+public class UserCommandController {
+
+    private final AddNewUser addNewUser;
+
+    @PostMapping("")
+    public ResponseEntity<String> addNewUser(@RequestBody AddUserCommand addUserCommand){
+        addNewUser.handle(addUserCommand);
+        return new ResponseEntity<>("New user was added to library", HttpStatus.CREATED);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/UserFacade.java

@@ -0,0 +1,25 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.AddUserCommand;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.EmailAddress;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.User;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.UserIdentifier;
+import io.wkrzywiec.hexagonal.library.domain.user.core.ports.incoming.AddNewUser;
+import io.wkrzywiec.hexagonal.library.domain.user.core.ports.outgoing.UserDatabase;
+import lombok.AllArgsConstructor;
+
+@AllArgsConstructor
+public class UserFacade implements AddNewUser {
+
+    private final UserDatabase database;
+
+    @Override
+    public UserIdentifier handle(AddUserCommand addUserCommand) {
+        User user = new User(
+                new EmailAddress(addUserCommand.getEmail()),
+                addUserCommand.getFirstName(),
+                addUserCommand.getLastName()
+        );
+        return database.save(user);
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/model/AddUserCommand.java

@@ -0,0 +1,17 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+public class AddUserCommand {
+
+    private String email;
+    private String firstName;
+    private String lastName;
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/model/EmailAddress.java

@@ -0,0 +1,28 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.model;
+
+import lombok.EqualsAndHashCode;
+
+import javax.persistence.Column;
+import javax.persistence.Embeddable;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@Embeddable
+@EqualsAndHashCode
+public class EmailAddress {
+
+    @Column(name="email")
+    private String value;
+
+    public EmailAddress(String value) {
+        Pattern pattern = Pattern.compile("^(.+)@(.+)$");
+        Matcher matcher = pattern.matcher(value);
+        if(matcher.matches()){
+            this.value = value;
+        } else {
+            throw new IllegalArgumentException("Provided value is not an email address");
+        }
+    }
+
+    private EmailAddress(){}
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/model/User.java

@@ -0,0 +1,43 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.model;
+
+import lombok.EqualsAndHashCode;
+
+import javax.persistence.Column;
+import javax.persistence.Embedded;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name="library_user")
+@EqualsAndHashCode
+public class User {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @EqualsAndHashCode.Exclude
+    private Long id;
+
+    @Embedded
+    private EmailAddress emailAddress;
+
+    @Column(name="first_name")
+    private String firstName;
+
+    @Column(name="last_name")
+    private String lastName;
+
+    public User(EmailAddress emailAddress, String firstName, String lastName) {
+        this.emailAddress = emailAddress;
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public Long getIdentifierAsLong(){
+        return id;
+    }
+
+    private User(){}
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/model/UserIdentifier.java

@@ -0,0 +1,15 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.model;
+
+
+public class UserIdentifier {
+
+    private final Long id;
+
+    public UserIdentifier(Long id) {
+        this.id = id;
+    }
+
+    public Long getAsLong(){
+        return id;
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/ports/incoming/AddNewUser.java

@@ -0,0 +1,8 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.ports.incoming;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.AddUserCommand;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.UserIdentifier;
+
+public interface AddNewUser {
+    UserIdentifier handle(AddUserCommand addUserCommand);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/core/ports/outgoing/UserDatabase.java

@@ -0,0 +1,8 @@
+package io.wkrzywiec.hexagonal.library.domain.user.core.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.User;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.UserIdentifier;
+
+public interface UserDatabase {
+    UserIdentifier save(User user);
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/infrastructure/UserDatabaseAdapter.java

@@ -0,0 +1,18 @@
+package io.wkrzywiec.hexagonal.library.domain.user.infrastructure;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.User;
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.UserIdentifier;
+import io.wkrzywiec.hexagonal.library.domain.user.core.ports.outgoing.UserDatabase;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class UserDatabaseAdapter implements UserDatabase {
+
+    private final UserRepository userRepository;
+
+    @Override
+    public UserIdentifier save(User user) {
+        User savedUser = userRepository.save(user);
+        return new UserIdentifier(savedUser.getIdentifierAsLong());
+    }
+}

src/main/java/io/wkrzywiec/hexagonal/library/domain/user/infrastructure/UserRepository.java

@@ -0,0 +1,9 @@
+package io.wkrzywiec.hexagonal.library.domain.user.infrastructure;
+
+import io.wkrzywiec.hexagonal.library.domain.user.core.model.User;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface UserRepository extends CrudRepository<User, Long> {
+}