Add support for background initialization of EntityManagerFactory

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/JpaBaseConfiguration.java

@@ -44,6 +44,7 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.context.annotation.Primary;
+import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.orm.jpa.JpaTransactionManager;
 import org.springframework.orm.jpa.JpaVendorAdapter;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
@@ -107,11 +108,13 @@ public JpaVendorAdapter jpaVendorAdapter() {
 	@ConditionalOnMissingBean
 	public EntityManagerFactoryBuilder entityManagerFactoryBuilder(
 			JpaVendorAdapter jpaVendorAdapter,
-			ObjectProvider<PersistenceUnitManager> persistenceUnitManagerProvider) {
+			ObjectProvider<PersistenceUnitManager> persistenceUnitManagerProvider,
+			ObjectProvider<AsyncTaskExecutor> bootstrapExecutorProvider) {
 		EntityManagerFactoryBuilder builder = new EntityManagerFactoryBuilder(
 				jpaVendorAdapter, this.properties.getProperties(),
 				persistenceUnitManagerProvider.getIfAvailable(),
-				determinePersistenceUnitRootLocation());
+				determinePersistenceUnitRootLocation(),
+				bootstrapExecutorProvider.getIfUnique());
 		builder.setCallback(getVendorCallback());
 		return builder;
 	}

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

@@ -41,13 +41,17 @@
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.orm.jpa.JpaTransactionManager;
 import org.springframework.orm.jpa.JpaVendorAdapter;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
 import org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager;
 import org.springframework.orm.jpa.persistenceunit.PersistenceUnitManager;
 import org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter;
 import org.springframework.orm.jpa.support.OpenEntityManagerInViewInterceptor;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 
@@ -58,6 +62,7 @@
  *
  * @author Phillip Webb
  * @author Dave Syer
+ * @author Vedran Pavic
  */
 public abstract class AbstractJpaAutoConfigurationTests {
 
@@ -196,6 +201,41 @@ public void customPersistenceUnitManager() throws Exception {
 				.isEqualTo(this.context.getBean(PersistenceUnitManager.class));
 	}
 
+	@Test
+	public void withTaskExecutor() {
+		setupTestConfiguration(TestConfigurationWithTaskExecutor.class);
+		this.context.refresh();
+		LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = this.context
+				.getBean(LocalContainerEntityManagerFactoryBean.class);
+		AsyncTaskExecutor bootstrapExecutor = (AsyncTaskExecutor) ReflectionTestUtils
+				.getField(entityManagerFactoryBean, "bootstrapExecutor");
+		assertThat(bootstrapExecutor).isEqualTo(
+				this.context.getBean(AsyncTaskExecutor.class));
+	}
+
+	@Test
+	public void withMultipleTaskExecutors() {
+		setupTestConfiguration(TestConfigurationWithMultipleTaskExecutors.class);
+		this.context.refresh();
+		LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = this.context
+				.getBean(LocalContainerEntityManagerFactoryBean.class);
+		AsyncTaskExecutor bootstrapExecutor = (AsyncTaskExecutor) ReflectionTestUtils
+				.getField(entityManagerFactoryBean, "bootstrapExecutor");
+		assertThat(bootstrapExecutor).isNull();
+	}
+
+	@Test
+	public void withPrimaryTaskExecutor() {
+		setupTestConfiguration(TestConfigurationWithPrimaryTaskExecutor.class);
+		this.context.refresh();
+		LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = this.context
+				.getBean(LocalContainerEntityManagerFactoryBean.class);
+		AsyncTaskExecutor bootstrapExecutor = (AsyncTaskExecutor) ReflectionTestUtils
+				.getField(entityManagerFactoryBean, "bootstrapExecutor");
+		assertThat(bootstrapExecutor).isEqualTo(
+				this.context.getBean("taskExecutorOne", AsyncTaskExecutor.class));
+	}
+
 	protected void setupTestConfiguration() {
 		setupTestConfiguration(TestConfiguration.class);
 	}
@@ -306,6 +346,47 @@ public PersistenceUnitManager persistenceUnitManager() {
 
 	}
 
+	@Configuration
+	protected static class TestConfigurationWithTaskExecutor extends TestConfiguration {
+
+		@Bean
+		public ThreadPoolTaskExecutor taskExecutor() {
+			return new ThreadPoolTaskExecutor();
+		}
+
+	}
+
+	@Configuration
+	protected static class TestConfigurationWithMultipleTaskExecutors extends TestConfiguration {
+
+		@Bean
+		public ThreadPoolTaskExecutor taskExecutorOne() {
+			return new ThreadPoolTaskExecutor();
+		}
+
+		@Bean
+		public ThreadPoolTaskExecutor taskExecutorTwo() {
+			return new ThreadPoolTaskExecutor();
+		}
+
+	}
+
+	@Configuration
+	protected static class TestConfigurationWithPrimaryTaskExecutor extends TestConfiguration {
+
+		@Bean
+		@Primary
+		public ThreadPoolTaskExecutor taskExecutorOne() {
+			return new ThreadPoolTaskExecutor();
+		}
+
+		@Bean
+		public ThreadPoolTaskExecutor taskExecutorTwo() {
+			return new ThreadPoolTaskExecutor();
+		}
+
+	}
+
 	@SuppressWarnings("serial")
 	static class CustomJpaTransactionManager extends JpaTransactionManager {
 	}

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

@@ -25,6 +25,7 @@
 
 import javax.sql.DataSource;
 
+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;
@@ -41,6 +42,7 @@
  * @author Dave Syer
  * @author Phillip Webb
  * @author Stephane Nicoll
+ * @author Vedran Pavic
  * @since 1.3.0
  */
 public class EntityManagerFactoryBuilder {
@@ -53,6 +55,8 @@ public class EntityManagerFactoryBuilder {
 
 	private final URL persistenceUnitRootLocation;
 
+	private final AsyncTaskExecutor bootstrapExecutor;
+
 	private EntityManagerFactoryBeanCallback callback;
 
 	/**
@@ -82,10 +86,31 @@ public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
 	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
 			Map<String, ?> jpaProperties, PersistenceUnitManager persistenceUnitManager,
 			URL persistenceUnitRootLocation) {
+		this(jpaVendorAdapter, jpaProperties, persistenceUnitManager,
+				persistenceUnitRootLocation, null);
+	}
+
+	/**
+	 * Create a new instance passing in the common pieces that will be shared if multiple
+	 * EntityManagerFactory instances are created.
+	 * @param jpaVendorAdapter a vendor adapter
+	 * @param jpaProperties JPA properties to be passed to the persistence provider.
+	 * @param persistenceUnitManager optional source of persistence unit information (can
+	 * be null)
+	 * @param persistenceUnitRootLocation the persistence unit root location to use as a
+	 * fallback (can be null)
+	 * @param bootstrapExecutor optional asynchronous executor for background
+	 * bootstrapping (can be null)
+	 * @since 1.5.0
+	 */
+	public EntityManagerFactoryBuilder(JpaVendorAdapter jpaVendorAdapter,
+			Map<String, ?> jpaProperties, PersistenceUnitManager persistenceUnitManager,
+			URL persistenceUnitRootLocation, AsyncTaskExecutor bootstrapExecutor) {
 		this.jpaVendorAdapter = jpaVendorAdapter;
 		this.persistenceUnitManager = persistenceUnitManager;
 		this.jpaProperties = new LinkedHashMap<String, Object>(jpaProperties);
 		this.persistenceUnitRootLocation = persistenceUnitRootLocation;
+		this.bootstrapExecutor = bootstrapExecutor;
 	}
 
 	public Builder dataSource(DataSource dataSource) {
@@ -192,7 +217,10 @@ public LocalContainerEntityManagerFactoryBean build() {
 			}
 			entityManagerFactoryBean.setJpaVendorAdapter(
 					EntityManagerFactoryBuilder.this.jpaVendorAdapter);
-
+			if (EntityManagerFactoryBuilder.this.bootstrapExecutor != null) {
+				entityManagerFactoryBean.setBootstrapExecutor(
+						EntityManagerFactoryBuilder.this.bootstrapExecutor);
+			}
 			if (this.jta) {
 				entityManagerFactoryBean.setJtaDataSource(this.dataSource);
 			}