BAEL-4565 Object States in Hibernate's Session (#10107)

persistence-modules/spring-boot-persistence-2/src/main/java/com/baeldung/states/Application.java

@@ -0,0 +1,12 @@
+package com.baeldung.states;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+    
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

persistence-modules/spring-boot-persistence-2/src/main/java/com/baeldung/states/UserEntity.java

@@ -0,0 +1,27 @@
+package com.baeldung.states;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+
+@Entity
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+public class UserEntity {
+    @Id
+    private String name;
+
+    @ManyToOne
+    private UserEntity manager;
+
+    public UserEntity(String name) {
+        this.name = name;
+    }
+}

persistence-modules/spring-boot-persistence-2/src/main/java/com/baeldung/states/UserEntityWithCascade.java

@@ -0,0 +1,28 @@
+package com.baeldung.states;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+
+@Entity
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+public class UserEntityWithCascade {
+    @Id
+    private String name;
+
+    @ManyToOne(cascade = CascadeType.PERSIST)
+    private UserEntityWithCascade manager;
+
+    public UserEntityWithCascade(String name) {
+        this.name = name;
+    }
+}

persistence-modules/spring-boot-persistence-2/src/test/java/com/baeldung/states/UserEntityIntegrationTest.java

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+package com.baeldung.states;
+
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
+import org.junit.jupiter.api.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import javax.persistence.EntityManagerFactory;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+class UserEntityIntegrationTest {
+    @Autowired
+    private EntityManagerFactory entityManagerFactory;
+
+    @Test
+    void givenName_thenShouldCreateDetachedUserEntity() {
+        // given
+        Session session = openSession();
+        UserEntity userEntity = new UserEntity("John");
+
+        // then
+        assertThat(session.contains(userEntity)).isFalse();
+        session.close();
+    }
+
+    @Test
+    void givenName_whenPersisted_thenShouldCreatePersistentUserEntity() {
+        // given
+        Session session = openSession();
+        UserEntity userEntity = new UserEntity("John");
+
+        // when
+        session.persist(userEntity);
+
+        // then
+        assertThat(session.contains(userEntity)).isTrue();
+        session.close();
+    }
+
+    @Test
+    void givenPersistentEntity_whenSessionClosed_thenShouldDetachEntity() {
+        // given
+        Session session = openSession();
+        UserEntity userEntity = new UserEntity("John");
+        session.persist(userEntity);
+        assertThat(session.contains(userEntity)).isTrue();
+
+        // when
+        session.close();
+
+        // then
+        assertThat(session.isOpen()).isFalse();
+        assertThatThrownBy(() -> session.contains(userEntity));
+    }
+
+    @Test
+    void givenPersistentEntity_whenAddedTransientManager_thenShouldThrowException() {
+        // given
+        Session session = openSession();
+        Transaction transaction = session.beginTransaction();
+        UserEntity userEntity = new UserEntity("John");
+        session.persist(userEntity);
+        UserEntity manager = new UserEntity("Adam");
+
+        // when
+        userEntity.setManager(manager);
+
+
+        // then
+        assertThatThrownBy(() -> {
+            session.saveOrUpdate(userEntity);
+            transaction.commit();
+        });
+        session.close();
+    }
+
+    @Test
+    void givenPersistentEntity_whenAddedPersistentManager_thenShouldSave() {
+        // given
+        Session session = openSession();
+        Transaction transaction = session.beginTransaction();
+        UserEntity userEntity = new UserEntity("John");
+        session.persist(userEntity);
+        UserEntity manager = new UserEntity("Adam");
+        session.persist(manager);
+
+        // when
+        userEntity.setManager(manager);
+
+
+        // then
+        session.saveOrUpdate(userEntity);
+        transaction.commit();
+        session.close();
+
+        Session otherSession = openSession();
+        UserEntity savedUser = otherSession.get(UserEntity.class, "John");
+        assertThat(savedUser.getManager().getName()).isEqualTo("Adam");
+    }
+
+    @Test
+    void givenPersistentEntityWithCascade_whenAddedTransientManager_thenShouldSave() {
+        // given
+        Session session = openSession();
+        Transaction transaction = session.beginTransaction();
+        UserEntityWithCascade userEntity = new UserEntityWithCascade("John");
+        session.persist(userEntity);
+        UserEntityWithCascade manager = new UserEntityWithCascade("Adam");
+
+        // when
+        userEntity.setManager(manager);
+
+
+        // then
+        session.saveOrUpdate(userEntity);
+        transaction.commit();
+        session.close();
+
+        Session otherSession = openSession();
+        UserEntityWithCascade savedUser = otherSession.get(UserEntityWithCascade.class, "John");
+        assertThat(savedUser.getManager().getName()).isEqualTo("Adam");
+    }
+
+
+    private Session openSession() {
+        return entityManagerFactory.unwrap(SessionFactory.class).openSession();
+    }
+}