readonly-transaction-demo example added

examples/readonly-transaction-demo/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+	<modelVersion>4.0.0</modelVersion>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.5.2</version>
+		<relativePath/> <!-- lookup parent from repository -->
+	</parent>
+
+	<groupId>ru.otus</groupId>
+	<artifactId>readonly-transaction-demo</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>readonly-transaction-demo</name>
+	<description>Readonly transaction demo</description>
+
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+
+	<dependencies>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+
+<!--
+		<dependency>
+			<groupId>org.postgresql</groupId>
+			<artifactId>postgresql</artifactId>
+		</dependency>
+-->
+
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<excludes>
+						<exclude>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok</artifactId>
+						</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

examples/readonly-transaction-demo/src/main/java/ru/otus/demo/ReadonlyTransactionDemoApplication.java

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+package ru.otus.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ReadonlyTransactionDemoApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(ReadonlyTransactionDemoApplication.class, args);
+	}
+
+}

examples/readonly-transaction-demo/src/main/java/ru/otus/demo/model/Person.java

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+package ru.otus.demo.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+@Entity
+public class Person {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+
+    private String name;
+
+}

examples/readonly-transaction-demo/src/main/java/ru/otus/demo/repository/PersonRepository.java

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+package ru.otus.demo.repository;
+
+import ru.otus.demo.model.Person;
+
+import java.util.List;
+
+public interface PersonRepository {
+
+    Person save(Person person);
+
+    List<Person> findAll();
+    Person findById(long id);
+}

examples/readonly-transaction-demo/src/main/java/ru/otus/demo/repository/PersonRepositoryJpa.java

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+package ru.otus.demo.repository;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Repository;
+import ru.otus.demo.model.Person;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.TypedQuery;
+import java.util.List;
+
+@Repository
+@RequiredArgsConstructor
+public class PersonRepositoryJpa implements PersonRepository {
+
+    @PersistenceContext
+    private final EntityManager em;
+
+    @Override
+    public Person save(Person person) {
+        if (person.getId() == 0) {
+            Person savedPerson = new Person(person.getId(), person.getName());
+            em.persist(savedPerson);
+            return savedPerson;
+
+        }
+        return em.merge(person);
+    }
+
+    @Override
+    public List<Person> findAll() {
+        TypedQuery<Person> query = em.createQuery("select p from Person p", Person.class);
+        return query.getResultList();
+    }
+
+    @Override
+    public Person findById(long id) {
+        TypedQuery<Person> query = em.createQuery("select p from Person p where p.id = :id", Person.class);
+        query.setParameter("id", id);
+        return query.getSingleResult();
+
+    }
+}

examples/readonly-transaction-demo/src/main/java/ru/otus/demo/services/PersonService.java

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+package ru.otus.demo.services;
+
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import ru.otus.demo.model.Person;
+import ru.otus.demo.repository.PersonRepository;
+
+@Service
+public class PersonService {
+    private final PersonRepository personRepository;
+
+    public PersonService(PersonRepository personRepository) {
+        this.personRepository = personRepository;
+    }
+
+    public Person findById(long id) {
+        return personRepository.findById(id);
+    }
+
+    @Transactional
+    public void save(Person person){
+        personRepository.save(person);
+    }
+
+    @Transactional
+    public void updateWithNormalTran(long id, String name) {
+        Person person = personRepository.findById(id);
+        person.setName(name);
+    }
+
+    @Transactional(readOnly = true)
+    public void updateWithReadonlyTran(long id, String name) {
+        Person person = personRepository.findById(id);
+        person.setName(name);
+    }
+}

examples/readonly-transaction-demo/src/main/resources/application.yml

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+spring:
+  datasource:
+    #url: jdbc:postgresql://localhost:5432/persons
+    #username: postgres
+    #password: postgres
+
+    url: jdbc:h2:mem:testdb
+
+    initialization-mode: always
+
+  jpa:
+    generate-ddl: false
+    hibernate:
+      ddl-auto: none
+
+    show-sql: true
+    properties:
+      hibernate:
+      #format_sql: true

examples/readonly-transaction-demo/src/main/resources/schema.sql

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+drop table if exists person;
+
+create table person  (
+    id bigserial,
+    name varchar(200),
+    primary key(id)
+);

examples/readonly-transaction-demo/src/test/java/ru/otus/demo/services/PersonServiceTest.java

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+package ru.otus.demo.services;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.transaction.annotation.Propagation;
+import org.springframework.transaction.annotation.Transactional;
+import ru.otus.demo.model.Person;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+@SpringBootTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@Transactional(propagation = Propagation.NOT_SUPPORTED)
+@DirtiesContext(classMode = DirtiesContext.ClassMode.BEFORE_EACH_TEST_METHOD)
+class PersonServiceTest {
+
+    @Autowired
+    private PersonService personService;
+
+    @BeforeEach
+    void setUp() {
+        personService.save(new Person(0, "Igor"));
+    }
+
+    @Test
+    void updateWithNormalTran() {
+        personService.updateWithNormalTran(1, "Vasya");
+        Person actualPerson = personService.findById(1);
+        assertThat(actualPerson).extracting(Person::getName).isEqualTo("Vasya");
+    }
+
+    @Test
+    void updateWithReadonlyTran() {
+        personService.updateWithReadonlyTran(1, "Vasya");
+        Person actualPerson = personService.findById(1);
+        assertThat(actualPerson).extracting(Person::getName).isEqualTo("Igor");
+    }
+}