Get published DataSource from EntityManager

Update DataSourceInitializedPublisher to always attempt to obtain the
published DataSource directly from the EntityManager. In the case where
the EntityManager doesn't provide a DataSource, the previous logic is
used.

Fixes gh-8296

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,20 +64,33 @@ class DataSourceInitializedPublisher implements BeanPostProcessor {
 		if (bean instanceof JpaProperties) {
 			this.properties = (JpaProperties) bean;
 		}
-		if (bean instanceof EntityManagerFactory && this.dataSource != null
-				&& isInitializingDatabase()) {
-			this.applicationContext
-					.publishEvent(new DataSourceInitializedEvent(this.dataSource));
+		if (bean instanceof EntityManagerFactory) {
+			publishEventIfRequired((EntityManagerFactory) bean);
 		}
 		return bean;
 	}
 
-	private boolean isInitializingDatabase() {
+	private void publishEventIfRequired(EntityManagerFactory entityManagerFactory) {
+		DataSource dataSource = findDataSource(entityManagerFactory);
+		if (dataSource != null && isInitializingDatabase(dataSource)) {
+			this.applicationContext
+					.publishEvent(new DataSourceInitializedEvent(dataSource));
+		}
+	}
+
+	private DataSource findDataSource(EntityManagerFactory entityManagerFactory) {
+		Object dataSource = entityManagerFactory.getProperties()
+				.get("javax.persistence.nonJtaDataSource");
+		return (dataSource != null && dataSource instanceof DataSource
+				? (DataSource) dataSource : this.dataSource);
+	}
+
+	private boolean isInitializingDatabase(DataSource dataSource) {
 		if (this.properties == null) {
 			return true; // better safe than sorry
 		}
 		Map<String, String> hibernate = this.properties
-				.getHibernateProperties(this.dataSource);
+				.getHibernateProperties(dataSource);
 		if (hibernate.containsKey("hibernate.hbm2ddl.auto")) {
 			return true;
 		}