HHH-7669 - Oracle sequences ordered

hibernate-envers/src/main/java/org/hibernate/envers/configuration/metadata/MetadataTools.java

@@ -49,7 +49,7 @@ public class MetadataTools {
         if (useRevisionEntityWithNativeId) {
             generator_mapping.addAttribute("class", "native");
         } else {
-            generator_mapping.addAttribute("class", "org.hibernate.id.enhanced.SequenceStyleGenerator");
+            generator_mapping.addAttribute("class", "org.hibernate.envers.enhanced.OrderedSequenceGenerator");
             generator_mapping.addElement("param").addAttribute("name", "sequence_name").setText("REVISION_GENERATOR");
             generator_mapping.addElement("param").addAttribute("name", "table_name").setText("REVISION_GENERATOR");
             generator_mapping.addElement("param").addAttribute("name", "initial_value").setText("1");

hibernate-envers/src/main/java/org/hibernate/envers/enhanced/OrderedSequenceGenerator.java

@@ -0,0 +1,23 @@
+package org.hibernate.envers.enhanced;
+
+import org.hibernate.HibernateException;
+import org.hibernate.dialect.Dialect;
+import org.hibernate.dialect.Oracle8iDialect;
+import org.hibernate.id.enhanced.SequenceStyleGenerator;
+import org.hibernate.internal.util.StringHelper;
+
+/**
+ * Revision number generator has to produce values in ascending order (gaps may occur).
+ * @author Lukasz Antoniak (lukasz dot antoniak at gmail dot com)
+ */
+public class OrderedSequenceGenerator extends SequenceStyleGenerator {
+	@Override
+	public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
+		String[] create = super.sqlCreateStrings( dialect );
+		if ( dialect instanceof Oracle8iDialect ) {
+			// Make sure that sequence produces increasing values in Oracle RAC environment.
+			create = StringHelper.suffix( create, " order" );
+		}
+		return create;
+	}
+}

hibernate-envers/src/main/java/org/hibernate/envers/enhanced/SequenceIdRevisionEntity.java

@@ -47,7 +47,7 @@ public class SequenceIdRevisionEntity implements Serializable {
     @Id
     @GeneratedValue(generator = "RevisionNumberSequenceGenerator")
     @GenericGenerator(name = "RevisionNumberSequenceGenerator",
-                      strategy = "org.hibernate.id.enhanced.SequenceStyleGenerator",
+                      strategy = "org.hibernate.envers.enhanced.OrderedSequenceGenerator",
                       parameters = {@Parameter(name = "table_name", value = "REVISION_GENERATOR"),
                                     @Parameter(name = "sequence_name", value = "REVISION_GENERATOR"),
                                     @Parameter(name = "initial_value", value = "1"),

hibernate-envers/src/test/java/org/hibernate/envers/test/integration/reventity/MonotonicRevisionNumberTest.java

@@ -0,0 +1,38 @@
+package org.hibernate.envers.test.integration.reventity;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.hibernate.dialect.Oracle8iDialect;
+import org.hibernate.envers.enhanced.OrderedSequenceGenerator;
+import org.hibernate.envers.enhanced.SequenceIdRevisionEntity;
+import org.hibernate.envers.test.BaseEnversFunctionalTestCase;
+import org.hibernate.envers.test.entities.StrIntTestEntity;
+import org.hibernate.id.IdentifierGenerator;
+import org.hibernate.persister.entity.EntityPersister;
+import org.hibernate.testing.RequiresDialect;
+import org.hibernate.testing.TestForIssue;
+
+/**
+ * @author Lukasz Antoniak (lukasz dot antoniak at gmail dot com)
+ */
+@TestForIssue(jiraKey = "HHH-7669")
+@RequiresDialect(Oracle8iDialect.class)
+public class MonotonicRevisionNumberTest extends BaseEnversFunctionalTestCase {
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[]{ StrIntTestEntity.class }; // Otherwise revision entity is not generated.
+	}
+
+	@Test
+	public void testOracleSequenceOrder() {
+		EntityPersister persister = sessionFactory().getEntityPersister( SequenceIdRevisionEntity.class.getName() );
+		IdentifierGenerator generator = persister.getIdentifierGenerator();
+		Assert.assertTrue( OrderedSequenceGenerator.class.isInstance( generator ) );
+		OrderedSequenceGenerator seqGenerator = (OrderedSequenceGenerator) generator;
+		Assert.assertTrue(
+				"Oracle sequence needs to be ordered in RAC environment.",
+				seqGenerator.sqlCreateStrings( getDialect() )[0].endsWith( " order" )
+		);
+	}
+}