Allow to configure PersistenceUnitPostProcessor

This commit updates EntityManagerFactoryBuilder so that persistence unit
post processors can be registered and applied when creating an
EntityManagerFactory.

See gh-25443

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/orm/jpa/AbstractJpaAutoConfigurationTests.java

@@ -21,6 +21,7 @@ import java.util.Map;
 import java.util.UUID;
 
 import javax.persistence.EntityManagerFactory;
+import javax.persistence.spi.PersistenceUnitInfo;
 import javax.sql.DataSource;
 
 import org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform;
@@ -229,6 +230,19 @@ abstract class AbstractJpaAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	void customPersistenceUnitPostProcessors() {
+		this.contextRunner.withUserConfiguration(TestConfigurationWithCustomPersistenceUnitPostProcessors.class)
+				.run((context) -> {
+					LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = context
+							.getBean(LocalContainerEntityManagerFactoryBean.class);
+					PersistenceUnitInfo persistenceUnitInfo = entityManagerFactoryBean.getPersistenceUnitInfo();
+					assertThat(persistenceUnitInfo).isNotNull();
+					assertThat(persistenceUnitInfo.getManagedClassNames())
+							.contains("customized.attribute.converter.class.name");
+				});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class TestTwoDataSourcesConfiguration {
 
@@ -388,6 +402,18 @@ abstract class AbstractJpaAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@TestAutoConfigurationPackage(AbstractJpaAutoConfigurationTests.class)
+	static class TestConfigurationWithCustomPersistenceUnitPostProcessors {
+
+		@Bean
+		EntityManagerFactoryBuilderCustomizer entityManagerFactoryBuilderCustomizer() {
+			return (builder) -> builder.setPersistenceUnitPostProcessors(
+					(pui) -> pui.addManagedClassName("customized.attribute.converter.class.name"));
+		}
+
+	}
+
 	@SuppressWarnings("serial")
 	static class CustomJpaTransactionManager extends JpaTransactionManager {
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/orm/jpa/EntityManagerFactoryBuilder.java

@@ -29,6 +29,7 @@ import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.orm.jpa.JpaVendorAdapter;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
 import org.springframework.orm.jpa.persistenceunit.PersistenceUnitManager;
+import org.springframework.orm.jpa.persistenceunit.PersistenceUnitPostProcessor;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
@@ -58,6 +59,8 @@ public class EntityManagerFactoryBuilder {
 
 	private AsyncTaskExecutor bootstrapExecutor;
 
+	private PersistenceUnitPostProcessor[] persistenceUnitPostProcessors;
+
 	/**
 	 * Create a new instance passing in the common pieces that will be shared if multiple
 	 * EntityManagerFactory instances are created.
@@ -104,6 +107,16 @@ public class EntityManagerFactoryBuilder {
 		this.bootstrapExecutor = bootstrapExecutor;
 	}
 
+	/**
+	 * Set the PersistenceUnitPostProcessors to be applied to the PersistenceUnitInfo used
+	 * for creating this EntityManagerFactory.
+	 * @param persistenceUnitPostProcessors internal persistence unit post processors
+	 * @since 2.5.0
+	 */
+	public void setPersistenceUnitPostProcessors(PersistenceUnitPostProcessor... persistenceUnitPostProcessors) {
+		this.persistenceUnitPostProcessors = persistenceUnitPostProcessors;
+	}
+
 	/**
 	 * A fluent builder for a LocalContainerEntityManagerFactoryBean.
 	 */
@@ -232,6 +245,8 @@ public class EntityManagerFactoryBuilder {
 			if (EntityManagerFactoryBuilder.this.bootstrapExecutor != null) {
 				entityManagerFactoryBean.setBootstrapExecutor(EntityManagerFactoryBuilder.this.bootstrapExecutor);
 			}
+			entityManagerFactoryBean
+					.setPersistenceUnitPostProcessors(EntityManagerFactoryBuilder.this.persistenceUnitPostProcessors);
 			return entityManagerFactoryBean;
 		}