hibernate identifiers examples (#2977)

* hibernate identifiers examples

* fix conflict

* change to longstream

* change to format

hibernate5/src/main/java/com/baeldung/hibernate/HibernateUtil.java

@@ -2,8 +2,17 @@ package com.baeldung.hibernate;
 
 import com.baeldung.hibernate.pojo.Employee;
 import com.baeldung.hibernate.pojo.EntityDescription;
+import com.baeldung.hibernate.pojo.OrderEntry;
+import com.baeldung.hibernate.pojo.OrderEntryIdClass;
+import com.baeldung.hibernate.pojo.OrderEntryPK;
+import com.baeldung.hibernate.pojo.Product;
 import com.baeldung.hibernate.pojo.Phone;
 import com.baeldung.hibernate.pojo.TemporalValues;
+import com.baeldung.hibernate.pojo.Course;
+import com.baeldung.hibernate.pojo.Student;
+import com.baeldung.hibernate.pojo.User;
+import com.baeldung.hibernate.pojo.UserProfile;
+
 import org.hibernate.SessionFactory;
 import org.hibernate.boot.Metadata;
 import org.hibernate.boot.MetadataSources;
@@ -33,6 +42,14 @@ public class HibernateUtil {
         metadataSources.addAnnotatedClass(Phone.class);
         metadataSources.addAnnotatedClass(EntityDescription.class);
         metadataSources.addAnnotatedClass(TemporalValues.class);
+        metadataSources.addAnnotatedClass(User.class);
+        metadataSources.addAnnotatedClass(Student.class);
+        metadataSources.addAnnotatedClass(Course.class);
+        metadataSources.addAnnotatedClass(Product.class);
+        metadataSources.addAnnotatedClass(OrderEntryPK.class);
+        metadataSources.addAnnotatedClass(OrderEntry.class);
+        metadataSources.addAnnotatedClass(OrderEntryIdClass.class);
+        metadataSources.addAnnotatedClass(UserProfile.class);
 
         Metadata metadata = metadataSources.buildMetadata();
         return metadata.getSessionFactoryBuilder()

hibernate5/src/main/java/com/baeldung/hibernate/pojo/Course.java

@@ -0,0 +1,27 @@
+package com.baeldung.hibernate.pojo;
+
+import java.util.UUID;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+@Entity
+public class Course {
+
+    @Id
+    @GeneratedValue
+    private UUID courseId;
+
+    public UUID getCourseId() {
+        return courseId;
+    }
+
+    public void setCourseId(UUID courseId) {
+        this.courseId = courseId;
+    }
+    
+    
+
+   
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/Department.java

@@ -0,0 +1,25 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.TableGenerator;
+
+@Entity
+public class Department {
+    @Id
+    @GeneratedValue(strategy = GenerationType.TABLE, generator="table-generator")
+    @TableGenerator (name="table-generator", table="dep_ids", pkColumnName="seq_id", valueColumnName="seq_value")
+    private long depId;
+
+    public long getDepId() {
+        return depId;
+    }
+
+    public void setDepId(long depId) {
+        this.depId = depId;
+    }
+    
+    
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/OrderEntry.java

@@ -0,0 +1,20 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.EmbeddedId;
+import javax.persistence.Entity;
+
+@Entity
+public class OrderEntry {
+
+    @EmbeddedId
+    private OrderEntryPK entryId;
+
+    public OrderEntryPK getEntryId() {
+        return entryId;
+    }
+
+    public void setEntryId(OrderEntryPK entryId) {
+        this.entryId = entryId;
+    }
+
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/OrderEntryIdClass.java

@@ -0,0 +1,31 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+
+@Entity
+@IdClass(OrderEntryPK.class)
+public class OrderEntryIdClass {
+    @Id
+    private long orderId;
+    @Id
+    private long productId;
+
+    public long getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(long orderId) {
+        this.orderId = orderId;
+    }
+
+    public long getProductId() {
+        return productId;
+    }
+
+    public void setProductId(long productId) {
+        this.productId = productId;
+    }
+
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/OrderEntryPK.java

@@ -0,0 +1,46 @@
+package com.baeldung.hibernate.pojo;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class OrderEntryPK implements Serializable {
+
+    private long orderId;
+    private long productId;
+
+    public long getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(long orderId) {
+        this.orderId = orderId;
+    }
+
+    public long getProductId() {
+        return productId;
+    }
+
+    public void setProductId(long productId) {
+        this.productId = productId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        OrderEntryPK pk = (OrderEntryPK) o;
+        return Objects.equals(orderId, pk.orderId) && Objects.equals(productId, pk.productId);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId, productId);
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/Product.java

@@ -0,0 +1,26 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+import org.hibernate.annotations.GenericGenerator;
+import org.hibernate.annotations.Parameter;
+
+@Entity
+public class Product {
+
+    @Id
+    @GeneratedValue(generator = "prod-generator")
+    @GenericGenerator(name = "prod-generator", parameters = @Parameter(name = "prefix", value = "prod"), strategy = "com.baeldung.hibernate.pojo.generator.MyGenerator")
+    private String prodId;
+
+    public String getProdId() {
+        return prodId;
+    }
+
+    public void setProdId(String prodId) {
+        this.prodId = prodId;
+    }
+
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/Student.java

@@ -0,0 +1,23 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Student {
+
+    @Id
+    @GeneratedValue (strategy = GenerationType.SEQUENCE)
+    private long studentId;
+
+    public long getStudentId() {
+        return studentId;
+    }
+
+    public void setStudent_id(long studentId) {
+        this.studentId = studentId;
+    }
+    
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/User.java

@@ -0,0 +1,24 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.SequenceGenerator;
+
+@Entity
+public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequence-generator")
+    @SequenceGenerator(name = "sequence-generator", sequenceName = "user_sequence", initialValue = 4)
+    private long userId;
+
+    public long getUserId() {
+        return userId;
+    }
+
+    public void setUserId(long userId) {
+        this.userId = userId;
+    }
+
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/UserProfile.java

@@ -0,0 +1,34 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.MapsId;
+import javax.persistence.OneToOne;
+
+@Entity
+public class UserProfile {
+
+    @Id
+    private long profileId;
+
+    @OneToOne
+    @MapsId
+    private User user;
+
+    public long getProfileId() {
+        return profileId;
+    }
+
+    public void setProfileId(long profileId) {
+        this.profileId = profileId;
+    }
+    
+    public User getUser() {
+        return user;
+    }
+
+    public void setUser(User user) {
+        this.user = user;
+    }
+    
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/generator/MyGenerator.java

@@ -0,0 +1,41 @@
+package com.baeldung.hibernate.pojo.generator;
+
+import java.io.Serializable;
+import java.util.Properties;
+import java.util.stream.Stream;
+
+import org.hibernate.HibernateException;
+import org.hibernate.MappingException;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.id.Configurable;
+import org.hibernate.id.IdentifierGenerator;
+import org.hibernate.service.ServiceRegistry;
+import org.hibernate.type.Type;
+
+public class MyGenerator implements IdentifierGenerator, Configurable {
+
+    private String prefix;
+
+    @Override
+    public Serializable generate(SharedSessionContractImplementor session, Object obj) throws HibernateException {
+
+        String query = String.format("select %s from %s", 
+            session.getEntityPersister(obj.getClass().getName(), obj).getIdentifierPropertyName(),
+            obj.getClass().getSimpleName());
+
+        Stream<String> ids = session.createQuery(query).stream();
+
+        Long max = ids.map(o -> o.replace(prefix + "-", ""))
+            .mapToLong(Long::parseLong)
+            .max()
+            .orElse(0L);
+
+        return prefix + "-" + (max + 1);
+    }
+
+    @Override
+    public void configure(Type type, Properties properties, ServiceRegistry serviceRegistry) throws MappingException {
+        prefix = properties.getProperty("prefix");
+    }
+
+}

hibernate5/src/test/java/com/baeldung/hibernate/IdentifiersIntegrationTest.java

@@ -0,0 +1,100 @@
+package com.baeldung.hibernate;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.hibernate.Transaction;
+import java.io.IOException;
+import org.hibernate.Session;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.baeldung.hibernate.pojo.Product;
+import com.baeldung.hibernate.pojo.Course;
+import com.baeldung.hibernate.pojo.OrderEntry;
+import com.baeldung.hibernate.pojo.OrderEntryIdClass;
+import com.baeldung.hibernate.pojo.OrderEntryPK;
+import com.baeldung.hibernate.pojo.Student;
+import com.baeldung.hibernate.pojo.User;
+import com.baeldung.hibernate.pojo.UserProfile;
+
+public class IdentifiersIntegrationTest {
+    private Session session;
+
+    private Transaction transaction;
+
+    @Before
+    public void setUp() throws IOException {
+        session = HibernateUtil.getSessionFactory()
+            .openSession();
+        transaction = session.beginTransaction();
+    }
+
+    @After
+    public void tearDown() {
+        transaction.rollback();
+        session.close();
+    }
+
+    @Test
+    public void whenSaveSimpleIdEntities_thenOk() {
+        Student student = new Student();
+        session.save(student);
+        User user = new User();
+        session.save(user);
+       
+        assertThat(student.getStudentId()).isEqualTo(1L);
+        assertThat(user.getUserId()).isEqualTo(4L);
+
+        Course course = new Course();
+        session.save(course);
+
+    }
+
+    @Test
+    public void whenSaveCustomGeneratedId_thenOk() {
+        Product product = new Product();
+        session.save(product);
+        Product product2 = new Product();
+        session.save(product2);
+
+        assertThat(product2.getProdId()).isEqualTo("prod-2");
+    }
+
+    @Test
+    public void whenSaveCompositeIdEntity_thenOk() {
+        OrderEntryPK entryPK = new OrderEntryPK();
+        entryPK.setOrderId(1L);
+        entryPK.setProductId(30L);
+
+        OrderEntry entry = new OrderEntry();
+        entry.setEntryId(entryPK);
+        session.save(entry);
+
+        assertThat(entry.getEntryId()
+            .getOrderId()).isEqualTo(1L);
+    }
+
+    @Test
+    public void whenSaveIdClassEntity_thenOk() {
+        OrderEntryIdClass entry = new OrderEntryIdClass();
+        entry.setOrderId(1L);
+        entry.setProductId(30L);
+        session.save(entry);
+
+        assertThat(entry.getOrderId()).isEqualTo(1L);
+    }
+
+    @Test
+    public void whenSaveDerivedIdEntity_thenOk() {
+        User user = new User();
+        session.save(user);
+
+        UserProfile profile = new UserProfile();
+        profile.setUser(user);
+        session.save(profile);
+
+        assertThat(profile.getProfileId()).isEqualTo(user.getUserId());
+    }
+
+}