Persistance context example

persistence-modules/spring-boot-persistence/src/main/java/com/baeldung/persistancecontext/PersistentContextDemoApplication.java

@@ -0,0 +1,13 @@
+package com.baeldung.persistancecontext;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+
+@SpringBootApplication
+@ComponentScan(basePackages="com.baeldung.persistancecontext")
+public class PersistentContextDemoApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(PersistentContextDemoApplication.class, args);
+    }
+}

persistence-modules/spring-boot-persistence/src/main/java/com/baeldung/persistancecontext/controller/UserController.java

@@ -0,0 +1,51 @@
+package com.baeldung.persistancecontext.controller;
+
+import org.springframework.beans.factory.annotation.Autowired;
+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.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.persistancecontext.entity.User;
+import com.baeldung.persistancecontext.service.ExtendedPersistenceContextUserService;
+import com.baeldung.persistancecontext.service.TransctionPersistenceContextUserService;
+
+@RestController
+public class UserController{
+
+    @Autowired
+    private TransctionPersistenceContextUserService userServiceTransctionPersistenceContext1;
+    @Autowired
+    private ExtendedPersistenceContextUserService userServiceExtendedPersistenceContext1;
+
+    @RequestMapping(value = "v1/user", method = RequestMethod.POST, consumes = "application/json", produces = "application/json")
+    public User saveUserV1(@RequestBody User user) {
+        return userServiceTransctionPersistenceContext1.insert(user);
+    }
+
+    @RequestMapping(value = "v2/user", method = RequestMethod.POST, consumes = "application/json", produces = "application/json")
+    public User saveUserV2(@RequestBody User user) {
+        return userServiceExtendedPersistenceContext1.insert(user);
+    }
+    
+    @RequestMapping(value = "v3/user", method = RequestMethod.POST, consumes = "application/json", produces = "application/json")
+    public User saveUserV3(@RequestBody User user) {
+        return userServiceExtendedPersistenceContext1.insertWithManagedTransaction(user);
+    }
+    
+    @RequestMapping(value = "v4/user", method = RequestMethod.POST, consumes = "application/json", produces = "application/json")
+    public User saveUserV4(@RequestBody User user) {
+        return userServiceTransctionPersistenceContext1.insertWithoutTransaction(user);
+    }
+
+    @RequestMapping(value = "v1/user/{id}", method = RequestMethod.GET, produces = "application/json")
+    public User getUserV1(@PathVariable("id") Long id) {
+        return userServiceTransctionPersistenceContext1.find(id);
+    }
+
+    @RequestMapping(value = "v2/user/{id}", method = RequestMethod.GET, produces = "application/json")
+    public User getUserV2(@PathVariable("id") Long id) {
+        return userServiceExtendedPersistenceContext1.find(id);
+    }
+}

persistence-modules/spring-boot-persistence/src/main/java/com/baeldung/persistancecontext/entity/User.java

@@ -0,0 +1,36 @@
+package com.baeldung.persistancecontext.entity;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+
+    @Id
+    private Long id;
+    private String name;
+    private String role;
+
+    public User() {
+
+    }
+
+    public User(Long id, String name, String role) {
+        this.id = id;
+        this.name = name;
+        this.role = role;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getRole() {
+        return role;
+    }
+
+}

persistence-modules/spring-boot-persistence/src/main/java/com/baeldung/persistancecontext/service/ExtendedPersistenceContextUserService.java

@@ -0,0 +1,37 @@
+package com.baeldung.persistancecontext.service;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.PersistenceContextType;
+import javax.transaction.Transactional;
+
+import org.springframework.stereotype.Component;
+
+import com.baeldung.persistancecontext.entity.User;
+
+@Component
+public class ExtendedPersistenceContextUserService {
+
+    @PersistenceContext(type = PersistenceContextType.EXTENDED)
+    private EntityManager entityManager;
+
+    public EntityManager getEntityManager() {
+        return entityManager;
+    }
+
+    public User insert(User user) {
+        entityManager.persist(user);
+        return user;
+    }
+
+    @Transactional
+    public User insertWithManagedTransaction(User user) {
+        entityManager.persist(user);
+        return user;
+    }
+
+    public User find(long id) {
+        User user = entityManager.find(User.class, id);
+        return user;
+    }
+}

persistence-modules/spring-boot-persistence/src/main/java/com/baeldung/persistancecontext/service/TransctionPersistenceContextUserService.java

@@ -0,0 +1,36 @@
+package com.baeldung.persistancecontext.service;
+
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.transaction.Transactional;
+
+import org.springframework.stereotype.Component;
+
+import com.baeldung.persistancecontext.entity.User;
+
+@Component
+public class TransctionPersistenceContextUserService {
+
+    @PersistenceContext
+    private EntityManager entityManager;
+    
+    public EntityManager getEntityManager() {
+        return entityManager;
+    }
+
+    @Transactional
+    public User insert(User user) {
+        entityManager.persist(user);
+        return user;
+    }
+    
+    public User insertWithoutTransaction(User user) {
+        entityManager.persist(user);
+        return user;
+    }
+    
+    public User find(long id) {
+        return entityManager.find(User.class, id);
+    }
+}

persistence-modules/spring-boot-persistence/src/test/java/com/baeldung/persistancecontext/PersistanceContextIntegrationTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.persistancecontext;
+
+import org.hamcrest.core.Is;
+import org.hamcrest.core.IsNull;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.web.client.HttpServerErrorException;
+import org.springframework.web.client.RestTemplate;
+
+import com.baeldung.persistancecontext.entity.User;
+
+import static org.junit.Assert.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = PersistentContextDemoApplication.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+
+public class PersistanceContextIntegrationTest {
+    @LocalServerPort
+    private int port;
+    private RestTemplate restTemplate;
+
+    @Before
+    public void setUp() {
+        restTemplate = new RestTemplate();
+    }
+
+    @Test
+    public void testThatWhenUserSavedWithTransctionPersistenceContextThenUserShouldGetSavedInDB() {
+        User user = new User(121L, "Devender", "admin");
+        restTemplate.postForEntity(buildRequestUrl("v1/user/"), user, User.class);
+        User userFromTransctionPersistenceContext = restTemplate.getForObject(buildRequestUrl("v1/user/121"), User.class);
+        User userFromExtendedPersistenceContext = restTemplate.getForObject(buildRequestUrl("v2/user/121"), User.class);
+        assertThat(userFromTransctionPersistenceContext, Is.is(IsNull.notNullValue()));
+        assertThat(userFromExtendedPersistenceContext, Is.is(IsNull.notNullValue()));
+    }
+
+    @Test(expected = HttpServerErrorException.class)
+    public void testThatWhenUserSaveWithOutTransactionInPersistanceContextTypeTransactionThenShouldFailOnPersist() {
+        User user = new User(122L, "Devender", "admin");
+        restTemplate.postForEntity(buildRequestUrl("v4/user/"), user, User.class);
+    }
+
+    @Test
+    public void testThatWhenUserSavedWithExtendedPersistenceContextWithoutTransactionThenUserShouldGetBeCached() {
+        User user = new User(123L, "Devender", "admin");
+        restTemplate.postForEntity(buildRequestUrl("v2/user/"), user, User.class);
+        User userFromExtendedPersistenceContext = restTemplate.getForObject(buildRequestUrl("v2/user/123"), User.class);
+        User userFromTransctionPersistenceContext = restTemplate.getForObject(buildRequestUrl("v1/user/123"), User.class);
+        assertThat(userFromExtendedPersistenceContext, Is.is(IsNull.notNullValue()));
+        assertThat(userFromTransctionPersistenceContext, Is.is(IsNull.nullValue()));
+    }
+
+    @Test
+    public void testThatWhenUserSavedWithExtendedPersistenceContextWithTransactionThenUserShouldFlushCachedEntityIntoDB() {
+        User user = new User(124L, "Devender", "admin");
+        restTemplate.postForEntity(buildRequestUrl("v2/user/"), user, User.class);
+        user = new User(125L, "Devender", "admin");
+        restTemplate.postForEntity(buildRequestUrl("v3/user/"), user, User.class);
+        User userFromExtendedPersistenceContextuser1 = restTemplate.getForObject(buildRequestUrl("v2/user/124"), User.class);
+        User userFromExtendedPersistenceContextuser2 = restTemplate.getForObject(buildRequestUrl("v2/user/125"), User.class);
+        User userFromTransctionPersistenceContextuser1 = restTemplate.getForObject(buildRequestUrl("v1/user/124"), User.class);
+        User userFromTransctionPersistenceContextuser2 = restTemplate.getForObject(buildRequestUrl("v1/user/125"), User.class);
+        assertThat(userFromExtendedPersistenceContextuser1, Is.is(IsNull.notNullValue()));
+        assertThat(userFromExtendedPersistenceContextuser2, Is.is(IsNull.notNullValue()));
+        assertThat(userFromTransctionPersistenceContextuser1, Is.is(IsNull.notNullValue()));
+        assertThat(userFromTransctionPersistenceContextuser2, Is.is(IsNull.notNullValue()));
+    }
+
+    private String buildRequestUrl(String path) {
+        return "http://localhost:" + port + path;
+    }
+}