INT-1039, Fixed missing assertion on MailMessage.to value

org.springframework.integration.mail/src/main/java/org/springframework/integration/mail/MailSendingMessageHandler.java

@@ -47,6 +47,7 @@ import org.springframework.util.StringUtils;
  * 
  * @author Marius Bogoevici
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 public class MailSendingMessageHandler implements MessageHandler {
 
@@ -127,7 +128,9 @@ public class MailSendingMessageHandler implements MessageHandler {
 			mailMessage.setSubject(subject);
 		}
 		String[] to = this.retrieveHeaderValueAsStringArray(headers, MailHeaders.TO);
-		mailMessage.setTo(to);
+		if (to != null){
+			mailMessage.setTo(to);
+		}	
 		if (mailMessage instanceof SimpleMailMessage) {
 			Assert.state(!ObjectUtils.isEmpty(((SimpleMailMessage) mailMessage).getTo()),
 					"No recipient has been provided on the MailMessage or the 'MailHeaders.TO' header.");
@@ -152,15 +155,18 @@ public class MailSendingMessageHandler implements MessageHandler {
 
 	private String[] retrieveHeaderValueAsStringArray(MessageHeaders headers, String key) {
 		Object value = headers.get(key);
+		String[] returnedHeaders = null;
 		if (value != null) {
 			if (value instanceof String[]) {
-				return (String[]) value;
-			}
-			if (value instanceof String) {
-				return StringUtils.commaDelimitedListToStringArray((String) value);
-			}
+				returnedHeaders = (String[]) value;
+			} else if (value instanceof String) {
+				returnedHeaders = StringUtils.commaDelimitedListToStringArray((String) value);
+			}	
 		}
-		return null;
+		if (returnedHeaders == null || ObjectUtils.isEmpty(returnedHeaders)){
+			returnedHeaders = null;
+		}
+		return returnedHeaders;
 	}
 
 }

org.springframework.integration.mail/src/test/java/org/springframework/integration/mail/MailSendingMessageHandlerTests.java

@@ -30,14 +30,14 @@ import javax.mail.internet.MimeMessage;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-
 import org.springframework.integration.message.MessageBuilder;
 import org.springframework.mail.SimpleMailMessage;
 
 /**
  * @author Marius Bogoevici
+ * @author Oleg Zhurakousky
  */
-public class MailSendingMessageHandlerTests {
+public class MailSendingMessageHandlerTests { 
 
 	private MailSendingMessageHandler handler;
 
@@ -49,7 +49,7 @@ public class MailSendingMessageHandlerTests {
 		this.mailSender = new StubJavaMailSender(new MimeMessage((Session) null));
 		this.handler = new MailSendingMessageHandler(this.mailSender);
 	}
-
+  
 	@After
 	public void reset() {
 		this.mailSender.reset();
@@ -99,5 +99,25 @@ public class MailSendingMessageHandlerTests {
 		assertEquals("message content different from expected",
 				mailMessage, mailSender.getSentSimpleMailMessages().get(0));
 	}
+	@Test
+	public void simpleMailMessage() {
+		SimpleMailMessage mailMessage = MailTestsHelper.createSimpleMailMessage();
+		String[] toHeaders = mailMessage.getTo();
+		this.handler.handleMessage(MessageBuilder.withPayload(mailMessage).build());
+		assertEquals("only one simple message must be sent",
+				1, mailSender.getSentSimpleMailMessages().size());
+		SimpleMailMessage sentMessage = mailSender.getSentSimpleMailMessages().get(0);
+		assertTrue(sentMessage.getTo().equals(toHeaders));
+	}
+	@Test
+	public void simpleMailMessageOverrideWithHeaders() {
+		SimpleMailMessage mailMessage = MailTestsHelper.createSimpleMailMessage();
+		String[] toHeaders = mailMessage.getTo();
+		this.handler.handleMessage(MessageBuilder.withPayload(mailMessage).setHeader(MailHeaders.TO, new String[]{"foo@bar.bam"}).build());
+		assertEquals("only one simple message must be sent",
+				1, mailSender.getSentSimpleMailMessages().size());
+		SimpleMailMessage sentMessage = mailSender.getSentSimpleMailMessages().get(0);
+		assertTrue(sentMessage.getTo()[0].equals("foo@bar.bam"));
+	}
 
 }