INT-3309 Pluggable MessageBuilder

This is still a work in process.

There are a bunch of TODOs in classes
that are not managed by Spring and so
need to have the MessageBuilderFactory
injected.

But I am looking for feedback on the
approach.

INT-3309 Resolve TODOs

Provide access to the MessageBuilderFactory in all classes.

INT-3309 Polishing + Tests

* Fallback to 'fromMessage()' if mutating and inbound message is not MutableMessage
* Add 'alwaysMutate' boolean to MutableMessageBuilderFactory - coerces 'fromMessage' calls to 'mutateMessage'
* Add tests

INT-3309 Polishing; PR Comments

Also add tests to parent/child contexts where the parent has the
default message builder and the child has a mutable message builder.

INT-3309 More Polish; PR Comments

Also fix removeHeader in MMB.

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

@@ -36,7 +36,6 @@ import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.integration.endpoint.MessageProducerSupport;
 import org.springframework.integration.mail.event.MailIntegrationEvent;
-import org.springframework.integration.support.MessageBuilder;
 import org.springframework.integration.transaction.IntegrationResourceHolder;
 import org.springframework.integration.transaction.TransactionSynchronizationFactory;
 import org.springframework.scheduling.TaskScheduler;
@@ -247,7 +246,7 @@ public class ImapIdleChannelAdapter extends MessageProducerSupport implements Be
 			@Override
 			public void run() {
 				org.springframework.messaging.Message<?> message =
-						MessageBuilder.withPayload(mailMessage).build();
+						ImapIdleChannelAdapter.this.getMessageBuilderFactory().withPayload(mailMessage).build();
 
 				if (TransactionSynchronizationManager.isActualTransactionActive()) {
 					if (transactionSynchronizationFactory != null){

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

@@ -22,10 +22,15 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.integration.context.IntegrationContextUtils;
+import org.springframework.integration.core.MessageSource;
+import org.springframework.integration.support.DefaultMessageBuilderFactory;
+import org.springframework.integration.support.MessageBuilderFactory;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessagingException;
-import org.springframework.integration.core.MessageSource;
-import org.springframework.integration.support.MessageBuilder;
 import org.springframework.util.Assert;
 
 /**
@@ -38,7 +43,8 @@ import org.springframework.util.Assert;
  * @author Gary Russell
  * @author Oleg Zhurakousky
  */
-public class MailReceivingMessageSource implements MessageSource<javax.mail.Message> {
+public class MailReceivingMessageSource implements MessageSource<javax.mail.Message>,
+		BeanFactoryAware {
 
 	private final Log logger = LogFactory.getLog(this.getClass());
 
@@ -46,12 +52,31 @@ public class MailReceivingMessageSource implements MessageSource<javax.mail.Mess
 
 	private final Queue<javax.mail.Message> mailQueue = new ConcurrentLinkedQueue<javax.mail.Message>();
 
+	private volatile BeanFactory beanFactory;
+
+	private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
+
 
 	public MailReceivingMessageSource(MailReceiver mailReceiver) {
 		Assert.notNull(mailReceiver, "mailReceiver must not be null");
 		this.mailReceiver = mailReceiver;
 	}
 
+	@Override
+	public final void setBeanFactory(BeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+		this.messageBuilderFactory = IntegrationContextUtils.getMessageBuilderFactory(this.beanFactory);
+	}
+
+	protected BeanFactory getBeanFactory() {
+		return beanFactory;
+	}
+
+	protected MessageBuilderFactory getMessageBuilderFactory() {
+		return messageBuilderFactory;
+	}
+
+	@Override
 	public Message<javax.mail.Message> receive() {
 		try {
 			javax.mail.Message mailMessage = this.mailQueue.poll();
@@ -66,7 +91,7 @@ public class MailReceivingMessageSource implements MessageSource<javax.mail.Mess
 				if (logger.isDebugEnabled()) {
 					logger.debug("received mail message [" + mailMessage + "]");
 				}
-				return MessageBuilder.withPayload(mailMessage).build();
+				return this.messageBuilderFactory.withPayload(mailMessage).build();
 			}
 		}
 		catch (Exception e) {

spring-integration-mail/src/main/java/org/springframework/integration/mail/transformer/AbstractMailMessageTransformer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -25,25 +25,47 @@ import javax.mail.Message.RecipientType;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.messaging.Message;
-import org.springframework.messaging.MessagingException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.integration.context.IntegrationContextUtils;
 import org.springframework.integration.mail.MailHeaders;
-import org.springframework.integration.support.MessageBuilder;
+import org.springframework.integration.support.AbstractIntegrationMessageBuilder;
+import org.springframework.integration.support.DefaultMessageBuilderFactory;
+import org.springframework.integration.support.MessageBuilderFactory;
 import org.springframework.integration.transformer.MessageTransformationException;
 import org.springframework.integration.transformer.Transformer;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessagingException;
 import org.springframework.util.Assert;
 
 /**
  * Base class for Transformers that convert from a JavaMail Message to a
  * Spring Integration Message.
- * 
+ *
  * @author Mark Fisher
+ * @author Gary Russell
  */
-public abstract class AbstractMailMessageTransformer<T> implements Transformer {
+public abstract class AbstractMailMessageTransformer<T> implements Transformer,
+		BeanFactoryAware {
 
 	protected final Log logger = LogFactory.getLog(this.getClass());
 
+	private volatile BeanFactory beanFactory;
 
+	private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
+
+
+	@Override
+	public final void setBeanFactory(BeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+		this.messageBuilderFactory = IntegrationContextUtils.getMessageBuilderFactory(this.beanFactory);
+	}
+
+	protected MessageBuilderFactory getMessageBuilderFactory() {
+		return messageBuilderFactory;
+	}
+
+	@Override
 	public Message<?> transform(Message<?> message) {
 		Object payload = message.getPayload();
 		if (!(payload instanceof javax.mail.Message)) {
@@ -51,7 +73,7 @@ public abstract class AbstractMailMessageTransformer<T> implements Transformer {
 					+ " requires a javax.mail.Message payload");
 		}
 		javax.mail.Message mailMessage = (javax.mail.Message) payload;
-		MessageBuilder<T> builder = null;
+		AbstractIntegrationMessageBuilder<T> builder = null;
 		try {
 			builder = this.doTransform(mailMessage);
 		}
@@ -65,7 +87,7 @@ public abstract class AbstractMailMessageTransformer<T> implements Transformer {
 		return builder.build();
 	}
 
-	protected abstract MessageBuilder<T> doTransform(javax.mail.Message mailMessage) throws Exception;
+	protected abstract AbstractIntegrationMessageBuilder<T> doTransform(javax.mail.Message mailMessage) throws Exception;
 
 
 	private Map<String, Object> extractHeaderMapFromMailMessage(javax.mail.Message mailMessage) {

spring-integration-mail/src/main/java/org/springframework/integration/mail/transformer/MailToStringTransformer.java

@@ -21,7 +21,7 @@ import java.nio.charset.Charset;
 
 import javax.mail.Multipart;
 
-import org.springframework.integration.support.MessageBuilder;
+import org.springframework.integration.support.AbstractIntegrationMessageBuilder;
 import org.springframework.util.Assert;
 
 /**
@@ -31,6 +31,7 @@ import org.springframework.util.Assert;
  * an output stream of bytes using the provided charset (or UTF-8 by default).
  *
  * @author Mark Fisher
+ * @author Gary Russell
  */
 public class MailToStringTransformer extends AbstractMailMessageTransformer<String> {
 
@@ -50,15 +51,15 @@ public class MailToStringTransformer extends AbstractMailMessageTransformer<Stri
 	}
 
 	@Override
-	protected MessageBuilder<String> doTransform(javax.mail.Message mailMessage) throws Exception {
+	protected AbstractIntegrationMessageBuilder<String> doTransform(javax.mail.Message mailMessage) throws Exception {
 		Object content = mailMessage.getContent();
 		if (content instanceof String) {
-			return MessageBuilder.withPayload((String) content);
+			return this.getMessageBuilderFactory().withPayload((String) content);
 		}
 		if (content instanceof Multipart) {
 			ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
 			((Multipart) content).writeTo(outputStream);
-			return MessageBuilder.withPayload(
+			return this.getMessageBuilderFactory().withPayload(
 					new String(outputStream.toByteArray(), this.charset));
 		}
 		throw new IllegalArgumentException("failed to transform contentType ["