INT-3623: Make MailSendingMH More Generic

JIRA: https://jira.spring.io/browse/INT-3623

**Cherry-pick to 4.1.x**

INT-3623: Address PR comments

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -23,6 +23,7 @@ import org.springframework.core.io.ByteArrayResource;
 import org.springframework.integration.handler.AbstractMessageHandler;
 import org.springframework.integration.mapping.MessageMappingException;
 import org.springframework.mail.MailMessage;
+import org.springframework.mail.MailSender;
 import org.springframework.mail.SimpleMailMessage;
 import org.springframework.mail.javamail.JavaMailSender;
 import org.springframework.mail.javamail.MimeMailMessage;
@@ -49,19 +50,19 @@ import org.springframework.util.StringUtils;
  * @author Marius Bogoevici
  * @author Mark Fisher
  * @author Oleg Zhurakousky
+ * @author Artem Bilan
  */
 public class MailSendingMessageHandler extends AbstractMessageHandler {
 
-	private final JavaMailSender mailSender;
+	private final MailSender mailSender;
 
 
 	/**
-	 * Create a MailSendingMessageConsumer.
-	 *
-	 * @param mailSender the {@link JavaMailSender} instance to which this
+	 * Create a MailSendingMessageHandler.
+	 * @param mailSender the {@link MailSender} instance to which this
 	 * adapter will delegate.
 	 */
-	public MailSendingMessageHandler(JavaMailSender mailSender) {
+	public MailSendingMessageHandler(MailSender mailSender) {
 		Assert.notNull(mailSender, "'mailSender' must not be null");
 		this.mailSender = mailSender;
 	}
@@ -73,12 +74,15 @@ public class MailSendingMessageHandler extends AbstractMessageHandler {
 
 	@Override
 	protected final void handleMessageInternal(Message<?> message) {
-		MailMessage mailMessage = this.convertMessageToMailMessage(message);
+		MailMessage mailMessage = convertMessageToMailMessage(message);
 		if (mailMessage instanceof SimpleMailMessage) {
 			this.mailSender.send((SimpleMailMessage) mailMessage);
 		}
 		else if (mailMessage instanceof MimeMailMessage) {
-			this.mailSender.send(((MimeMailMessage) mailMessage).getMimeMessage());
+			Assert.state(this.mailSender instanceof JavaMailSender,
+					"this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'");
+
+			((JavaMailSender) this.mailSender).send(((MimeMailMessage) mailMessage).getMimeMessage());
 		}
 		else {
 			throw new IllegalArgumentException(
@@ -111,25 +115,32 @@ public class MailSendingMessageHandler extends AbstractMessageHandler {
 		}
 		else {
 			throw new MessageHandlingException(message, "Unable to create MailMessage from payload type ["
-					+ message.getPayload().getClass().getName() + "], expected MimeMessage, MailMessage, byte array or String.");
+					+ message.getPayload().getClass().getName() + "], " +
+					"expected MimeMessage, MailMessage, byte array or String.");
 		}
 		this.applyHeadersToMailMessage(mailMessage, message.getHeaders());
 		return mailMessage;
 	}
 
 	private MailMessage createMailMessageWithContentType(Message<String> message, String contentType){
-		MimeMessage mimeMessage = this.mailSender.createMimeMessage();
+		Assert.state(this.mailSender instanceof JavaMailSender,
+				"this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'");
+
+		MimeMessage mimeMessage = ((JavaMailSender) this.mailSender).createMimeMessage();
 		try {
 			mimeMessage.setContent(message.getPayload(), contentType);
 			return new MimeMailMessage(mimeMessage);
 		}
 		catch (Exception e) {
-			throw new org.springframework.messaging.MessagingException("Failed to creaet MimeMessage with contentType: " +
-																			contentType, e);
+			throw new org.springframework.messaging.MessagingException("Failed to create MimeMessage with contentType: "
+					+ contentType, e);
 		}
 	}
 
 	private MailMessage createMailMessageFromByteArrayMessage(Message<byte[]> message) {
+		Assert.state(this.mailSender instanceof JavaMailSender,
+				"this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'");
+
 		String attachmentFileName = message.getHeaders().get(MailHeaders.ATTACHMENT_FILENAME, String.class);
 		if (attachmentFileName == null) {
 			throw new MessageMappingException(message, "Header '" + MailHeaders.ATTACHMENT_FILENAME
@@ -139,7 +150,8 @@ public class MailSendingMessageHandler extends AbstractMessageHandler {
 		if (multipartMode == null) {
 			multipartMode = MimeMessageHelper.MULTIPART_MODE_MIXED;
 		}
-		MimeMessage mimeMessage = this.mailSender.createMimeMessage();
+
+		MimeMessage mimeMessage = ((JavaMailSender) this.mailSender).createMimeMessage();
 		try {
 			MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, multipartMode);
 			helper.addAttachment(attachmentFileName, new ByteArrayResource(message.getPayload()));

spring-integration-mail/src/test/java/log4j.properties

@@ -1,4 +1,4 @@
-log4j.rootCategory=DEBUG, stdout
+log4j.rootCategory=WARN, stdout
 
 log4j.appender.stdout=org.apache.log4j.ConsoleAppender
 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

spring-integration-mail/src/test/java/org/springframework/integration/mail/MailSendingMessageHandlerContextTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -16,10 +16,14 @@
 
 package org.springframework.integration.mail;
 
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.instanceOf;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 import java.io.DataInputStream;
 
@@ -34,11 +38,12 @@ import org.junit.runner.RunWith;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.messaging.MessageChannel;
 import org.springframework.integration.mapping.MessageMappingException;
-import org.springframework.messaging.support.GenericMessage;
 import org.springframework.integration.support.MessageBuilder;
 import org.springframework.mail.SimpleMailMessage;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.MessageHandlingException;
+import org.springframework.messaging.support.GenericMessage;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
@@ -47,7 +52,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
  * @author Artem Bilan
  */
 @RunWith(value = SpringJUnit4ClassRunner.class)
-@ContextConfiguration(locations = {"classpath:/org/springframework/integration/mail/mailSendingMessageHandlerContextTests.xml"})
+@ContextConfiguration
 public class MailSendingMessageHandlerContextTests {
 
 	@Autowired
@@ -57,9 +62,15 @@ public class MailSendingMessageHandlerContextTests {
 	@Autowired
 	private StubJavaMailSender mailSender;
 
+	@Autowired
+	private StubMailSender simpleMailSender;
+
 	@Autowired
 	private MessageChannel sendMailOutboundChainChannel;
 
+	@Autowired
+	private MessageChannel simpleEmailChannel;
+
 	@Autowired
 	private BeanFactory beanFactory;
 
@@ -121,4 +132,47 @@ public class MailSendingMessageHandlerContextTests {
 		assertEquals("message content different from expected", mailMessage, this.mailSender.getSentSimpleMailMessages().get(0));
 	}
 
+	@Test
+	public void testOutboundChannelAdapterWithSimpleMailSender() {
+		this.simpleEmailChannel.send(MailTestsHelper.createIntegrationMessage());
+		assertEquals(1, this.simpleMailSender.getSentMessages().size());
+		assertEquals(MailTestsHelper.createSimpleMailMessage(), this.simpleMailSender.getSentMessages().get(0));
+
+		try {
+			this.simpleEmailChannel.send(new GenericMessage<byte[]>(new byte[0]));
+			fail("IllegalStateException expected");
+		}
+		catch (Exception e) {
+			assertThat(e, instanceOf(MessageHandlingException.class));
+			assertThat(e.getCause(), instanceOf(IllegalStateException.class));
+			assertThat(e.getMessage(), 
+					containsString("this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'"));
+		}
+
+		try {
+			this.simpleEmailChannel.send(MessageBuilder.withPayload("foo")
+					.setHeader(MailHeaders.CONTENT_TYPE, "text/plain")
+					.setHeader(MailHeaders.TO, "foo@com.foo")
+					.build());
+			fail("IllegalStateException expected");
+		}
+		catch (Exception e) {
+			assertThat(e, instanceOf(MessageHandlingException.class));
+			assertThat(e.getCause(), instanceOf(IllegalStateException.class));
+			assertThat(e.getMessage(), 
+					containsString("this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'"));
+		}
+
+		try {
+			this.simpleEmailChannel.send(new GenericMessage<MimeMessage>(this.mailSender.createMimeMessage()));
+			fail("IllegalStateException expected");
+		}
+		catch (Exception e) {
+			assertThat(e, instanceOf(MessageHandlingException.class));
+			assertThat(e.getCause(), instanceOf(IllegalStateException.class));
+			assertThat(e.getMessage(), 
+					containsString("this adapter requires a 'JavaMailSender' to send a 'MimeMailMessage'"));
+		}
+	}
+
 }

spring-integration-mail/src/test/java/org/springframework/integration/mail/StubMailSender.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2015 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.integration.mail;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.mail.MailException;
+import org.springframework.mail.MailSender;
+import org.springframework.mail.SimpleMailMessage;
+
+/**
+ * @author Artem Bilan
+ * @since 4.1.3
+ */
+public class StubMailSender implements MailSender {
+
+	private final List<SimpleMailMessage> sentMessages = new ArrayList<SimpleMailMessage>();
+
+	@Override
+	public void send(SimpleMailMessage simpleMessage) throws MailException {
+		this.sentMessages.add(simpleMessage);
+	}
+
+	@Override
+	public void send(SimpleMailMessage... simpleMessages) throws MailException {
+		this.sentMessages.addAll(Arrays.asList(simpleMessages));
+	}
+
+	public List<SimpleMailMessage> getSentMessages() {
+		return this.sentMessages;
+	}
+
+	public void reset() {
+		this.sentMessages.clear();
+	}
+
+}

spring-integration-mail/src/test/java/org/springframework/integration/mail/mailSendingMessageHandlerContextTests-context.xml

@@ -25,4 +25,8 @@
 		<int-mail:outbound-channel-adapter id="mail-outbound-channel-adapter-within-chain" mail-sender="javaMailSender"/>
 	</int:chain>
 
+	<bean id="mailSender" class="org.springframework.integration.mail.StubMailSender"/>
+
+	<int-mail:outbound-channel-adapter id="simpleEmailChannel" mail-sender="mailSender"/>
+
 </beans>