[bs-127] Add DataSourceTransactionManager if no others are in use

* If the auto config class has a high Order it can check for
an existing transaction manager
* Unit tests added, and checked also witrh petclinic

[Fixes #50064347]

spring-bootstrap/src/main/java/org/springframework/bootstrap/autoconfigure/jdbc/DataSourceTransactionManagerAutoConfiguration.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2012-2013 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.bootstrap.autoconfigure.jdbc;
+
+import javax.sql.DataSource;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.bootstrap.context.annotation.ConditionalOnBean;
+import org.springframework.bootstrap.context.annotation.ConditionalOnClass;
+import org.springframework.bootstrap.context.annotation.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
+import org.springframework.transaction.PlatformTransactionManager;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+@Configuration
+@ConditionalOnClass({ JdbcTemplate.class, PlatformTransactionManager.class })
+public class DataSourceTransactionManagerAutoConfiguration implements Ordered {
+
+	@Override
+	public int getOrder() {
+		return Integer.MAX_VALUE;
+	}
+
+	@Autowired(required = false)
+	private DataSource dataSource;
+
+	@Bean
+	@ConditionalOnMissingBean(name = "transactionManager")
+	@ConditionalOnBean(DataSource.class)
+	public PlatformTransactionManager transactionManager() {
+		return new DataSourceTransactionManager(this.dataSource);
+	}
+
+}

spring-bootstrap/src/main/resources/META-INF/spring.factories

@@ -4,6 +4,7 @@ org.springframework.bootstrap.autoconfigure.MessageSourceAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.jdbc.DataSourceAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.data.JpaRepositoriesAutoConfiguration,\
+org.springframework.bootstrap.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.batch.BatchAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
 org.springframework.bootstrap.autoconfigure.web.EmbeddedContainerCustomizerConfiguration,\