Use transactional connection during db population

Previously, DatabasePopulatorUtils#execute looked up a Connection from
the given DataSource directly which resulted in the executed statements
not being executed against a transactional connection (if any) which in
turn resulted in the statements executed by the populator potentially
not being rolled back.

Now DataSourceUtils#getConnection is used to transparently take part in
any active transaction and #releaseConnection is used to ensure the
connection is closed if appropriate.

Issue: SPR-9457

spring-jdbc/src/test/java/org/springframework/jdbc/datasource/init/DatabasePopulatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -19,17 +19,24 @@ package org.springframework.jdbc.datasource.init;
 import static org.junit.Assert.assertEquals;
 
 import java.sql.Connection;
+import java.sql.SQLException;
+
+import org.easymock.EasyMock;
 
 import org.junit.After;
 import org.junit.Test;
+
 import org.springframework.core.io.ClassRelativeResourceLoader;
 import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.datasource.DataSourceUtils;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabase;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
+import org.springframework.transaction.support.TransactionSynchronizationManager;
 
 /**
  * @author Dave Syer
  * @author Sam Brannen
+ * @author Oliver Gierke
  */
 public class DatabasePopulatorTests {
 
@@ -54,6 +61,12 @@ public class DatabasePopulatorTests {
 
 	@After
 	public void shutDown() {
+
+		if (TransactionSynchronizationManager.isSynchronizationActive()) {
+			TransactionSynchronizationManager.clear();
+			TransactionSynchronizationManager.unbindResource(db);
+		}
+
 		db.shutdown();
 	}
 
@@ -207,4 +220,22 @@ public class DatabasePopulatorTests {
 		assertEquals(1, jdbcTemplate.queryForInt("select COUNT(NAME) from T_TEST where NAME='Dave'"));
 	}
 
+	/**
+	 * @see SPR-9457
+	 */
+	@Test
+	public void usesBoundConnectionIfAvailable() throws SQLException {
+
+		TransactionSynchronizationManager.initSynchronization();
+		Connection connection = DataSourceUtils.getConnection(db);
+
+		DatabasePopulator populator = EasyMock.createMock(DatabasePopulator.class);
+		populator.populate(connection);
+		EasyMock.expectLastCall();
+		EasyMock.replay(populator);
+
+		DatabasePopulatorUtils.execute(populator, db);
+
+		EasyMock.verify(populator);
+	}
 }