BAEL-4723 Defining Indexes in JPA (#10247)

* BAEL-4723 Defining Indexes in JPA

* unit -> integration test

Co-authored-by: mateusz.szablak <mateusz.szablak@accenture.com>

persistence-modules/java-jpa-3/src/main/java/com/baeldung/jpa/index/Student.java

@@ -0,0 +1,70 @@
+package com.baeldung.jpa.index;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.Index;
+import javax.persistence.Table;
+import java.io.Serializable;
+import java.util.Objects;
+
+@Entity
+@Table(indexes = {
+        @Index(columnList = "firstName"),
+        @Index(name = "fn_index", columnList = "id"),
+        @Index(name = "multiIndex1", columnList = "firstName, lastName"),
+        @Index(name = "multiIndex2", columnList = "lastName, firstName"),
+        @Index(name = "multiSortIndex", columnList = "firstName, lastName DESC"),
+        @Index(name = "uniqueIndex", columnList = "firstName", unique = true),
+        @Index(name = "uniqueMultiIndex", columnList = "firstName, lastName", unique = true)
+})
+public class Student implements Serializable {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String firstName;
+    private String lastName;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Student student = (Student) o;
+        return Objects.equals(id, student.id) &&
+                Objects.equals(firstName, student.firstName) &&
+                Objects.equals(lastName, student.lastName);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, firstName, lastName);
+    }
+}

persistence-modules/java-jpa-3/src/main/resources/META-INF/persistence.xml

@@ -40,4 +40,19 @@
             <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
         </properties>
     </persistence-unit>
+    <persistence-unit name="jpa-index">
+		    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+		    <class>com.baeldung.jpa.index.Student</class>
+		    <exclude-unlisted-classes>true</exclude-unlisted-classes>
+		    <properties>
+		    	<property name="javax.persistence.jdbc.driver" value="org.h2.Driver" />
+		    	<property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:test" />
+		    	<property name="javax.persistence.jdbc.user" value="sa" />
+		    	<property name="javax.persistence.jdbc.password" value="" />
+   			<property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
+   			<property name="hibernate.hbm2ddl.auto" value="create-drop" />
+   			<property name="show_sql" value="true" />
+   			<property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />
+   		</properties>
+   	</persistence-unit>
 </persistence>

persistence-modules/java-jpa-3/src/main/resources/logback.xml

@@ -8,7 +8,7 @@
             </pattern>
         </encoder>
     </appender>
-
+    <logger name="org.hibernate.SQL" level="DEBUG" />
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>

persistence-modules/java-jpa-3/src/test/java/com/baeldung/jpa/index/IndexIntegrationTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.jpa.index;
+
+import org.hibernate.exception.ConstraintViolationException;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import java.util.Optional;
+
+public class IndexIntegrationTest {
+    private static EntityManagerFactory factory;
+    private static EntityManager entityManager;
+
+    @BeforeClass
+    public static void setup() {
+        factory = Persistence.createEntityManagerFactory("jpa-index");
+        entityManager = factory.createEntityManager();
+    }
+
+    @Test
+    public void givenStudent_whenPersistStudentWithSameFirstName_thenConstraintViolationException() {
+        Student student = new Student();
+        student.setFirstName("FirstName");
+        student.setLastName("LastName");
+
+        Student student2 = new Student();
+        student2.setFirstName("FirstName");
+        student2.setLastName("LastName2");
+
+        entityManager.getTransaction().begin();
+        entityManager.persist(student);
+        entityManager.getTransaction().commit();
+
+        Assert.assertEquals(1L, (long) student.getId());
+
+        entityManager.getTransaction().begin();
+        try {
+            entityManager.persist(student2);
+            entityManager.getTransaction().commit();
+            Assert.fail("Should raise an exception - unique key violation");
+        } catch (Exception ex) {
+            Assert.assertTrue(Optional.of(ex).map(Throwable::getCause).map(Throwable::getCause).filter(x -> x instanceof ConstraintViolationException).isPresent());
+        } finally {
+            entityManager.getTransaction().rollback();
+        }
+    }
+}