Added test examples for the article "Hibernate: save, persist, update, merge, saveOrUpdate" (#487)

spring-hibernate4/README.md

@@ -9,6 +9,7 @@
 - [Sorting with Hibernate](http://www.baeldung.com/hibernate-sort)
 - [Auditing with JPA, Hibernate, and Spring Data JPA](http://www.baeldung.com/database-auditing-jpa)
 - [Stored Procedures with Hibernate](http://www.baeldung.com/stored-procedures-with-hibernate-tutorial)
+- [Hibernate: save, persist, update, merge, saveOrUpdate](http://www.baeldung.com/hibernate-save-persist-update-merge-saveorupdate/)
 
 ### Quick Start
 

spring-hibernate4/pom.xml

@@ -149,6 +149,13 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.hsqldb</groupId>
+            <artifactId>hsqldb</artifactId>
+            <version>2.3.4</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <build>

spring-hibernate4/src/main/java/com/baeldung/persistence/model/Person.java

@@ -0,0 +1,31 @@
+package com.baeldung.persistence.model;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+@Entity
+public class Person {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

spring-hibernate4/src/test/java/com/baeldung/persistence/save/SaveMethodsTest.java

@@ -0,0 +1,272 @@
+package com.baeldung.persistence.save;
+
+
+import com.baeldung.persistence.model.Person;
+import org.hibernate.HibernateException;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.dialect.HSQLDialect;
+import org.hibernate.service.ServiceRegistry;
+import org.junit.*;
+
+import static org.junit.Assert.*;
+
+/**
+ * Testing specific implementation details for different methods:
+ * persist, save, merge, update, saveOrUpdate.
+ */
+public class SaveMethodsTest {
+
+    private static SessionFactory sessionFactory;
+
+    private Session session;
+
+    @BeforeClass
+    public static void beforeTests() {
+        Configuration configuration = new Configuration()
+                .addAnnotatedClass(Person.class)
+                .setProperty("hibernate.dialect", HSQLDialect.class.getName())
+                .setProperty("hibernate.connection.driver_class", org.hsqldb.jdbcDriver.class.getName())
+                .setProperty("hibernate.connection.url", "jdbc:hsqldb:mem:test")
+                .setProperty("hibernate.connection.username", "sa")
+                .setProperty("hibernate.connection.password", "")
+                .setProperty("hibernate.hbm2ddl.auto", "update");
+        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(
+                configuration.getProperties()).build();
+        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
+    }
+
+    @Before
+    public void setUp() {
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+    }
+
+
+    @Test
+    public void whenPersistTransient_thenSavedToDatabaseOnCommit() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.persist(person);
+
+        session.getTransaction().commit();
+        session.close();
+
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+
+        assertNotNull(session.get(Person.class, person.getId()));
+
+    }
+
+    @Test
+    public void whenPersistPersistent_thenNothingHappens() {
+
+        Person person = new Person();
+        person.setName("John");
+
+        session.persist(person);
+        Long id1 = person.getId();
+
+        session.persist(person);
+        Long id2 = person.getId();
+
+        assertEquals(id1, id2);
+    }
+
+    @Test(expected = HibernateException.class)
+    public void whenPersistDetached_thenThrowsException() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.persist(person);
+        session.evict(person);
+
+        session.persist(person);
+
+    }
+
+    @Test
+    public void whenSaveTransient_thenIdGeneratedImmediately() {
+
+        Person person = new Person();
+        person.setName("John");
+
+        assertNull(person.getId());
+
+        Long id = (Long) session.save(person);
+
+        assertNotNull(id);
+
+        session.getTransaction().commit();
+        session.close();
+
+        assertEquals(id, person.getId());
+
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+
+        assertNotNull(session.get(Person.class, person.getId()));
+
+    }
+
+    @Test
+    public void whenSavePersistent_thenNothingHappens() {
+
+        Person person = new Person();
+        person.setName("John");
+        Long id1 = (Long) session.save(person);
+        Long id2 = (Long) session.save(person);
+        assertEquals(id1, id2);
+
+    }
+
+    @Test
+    public void whenSaveDetached_thenNewInstancePersisted() {
+
+        Person person = new Person();
+        person.setName("John");
+        Long id1 = (Long) session.save(person);
+        session.evict(person);
+
+        Long id2 = (Long) session.save(person);
+        assertNotEquals(id1, id2);
+
+    }
+
+    @Test
+    public void whenMergeDetached_thenEntityUpdatedFromDatabase() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+        session.evict(person);
+
+        person.setName("Mary");
+        Person mergedPerson = (Person) session.merge(person);
+
+        assertNotSame(person, mergedPerson);
+        assertEquals("Mary", mergedPerson.getName());
+
+    }
+
+    @Test
+    public void whenMergeTransient_thenNewEntitySavedToDatabase() {
+
+        Person person = new Person();
+        person.setName("John");
+        Person mergedPerson = (Person) session.merge(person);
+
+        session.getTransaction().commit();
+        session.beginTransaction();
+
+        assertNull(person.getId());
+        assertNotNull(mergedPerson.getId());
+
+    }
+
+    @Test
+    public void whenMergePersistent_thenReturnsSameObject() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+
+        Person mergedPerson = (Person) session.merge(person);
+
+        assertSame(person, mergedPerson);
+
+    }
+
+    @Test
+    public void whenUpdateDetached_thenEntityUpdatedFromDatabase() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+        session.evict(person);
+
+        person.setName("Mary");
+        session.update(person);
+        assertEquals("Mary", person.getName());
+
+    }
+
+    @Test(expected = HibernateException.class)
+    public void whenUpdateTransient_thenThrowsException() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.update(person);
+
+    }
+
+    @Test
+    public void whenUpdatePersistent_thenNothingHappens() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+
+        session.update(person);
+
+    }
+
+    @Test
+    public void whenSaveOrUpdateDetached_thenEntityUpdatedFromDatabase() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+        session.evict(person);
+
+        person.setName("Mary");
+        session.saveOrUpdate(person);
+        assertEquals("Mary", person.getName());
+
+    }
+
+    @Test
+    public void whenSaveOrUpdateTransient_thenSavedToDatabaseOnCommit() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.saveOrUpdate(person);
+
+        session.getTransaction().commit();
+        session.close();
+
+        session = sessionFactory.openSession();
+        session.beginTransaction();
+
+        assertNotNull(session.get(Person.class, person.getId()));
+
+
+    }
+
+    @Test
+    public void whenSaveOrUpdatePersistent_thenNothingHappens() {
+
+        Person person = new Person();
+        person.setName("John");
+        session.save(person);
+
+        session.saveOrUpdate(person);
+
+    }
+
+    @After
+    public void tearDown() {
+        session.getTransaction().commit();
+        session.close();
+    }
+
+    @AfterClass
+    public static void afterTests() {
+        sessionFactory.close();
+    }
+
+}