Added MessageHeaders and MessageBuilder. Messages are now immutable (including header maps).

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/ResultToDocumentTransformer.java

@@ -66,7 +66,7 @@ public class ResultToDocumentTransformer implements MessageTransformer {
 			throw new MessagingException(message, "Failed to create document from payload type ["
 					+ message.getPayload().getClass().getName() + "]");
 		}
-		return new GenericMessage<Document>(doc, message.getHeader());
+		return new GenericMessage<Document>(doc, message.getHeaders());
 	}
 
 	@SuppressWarnings("unchecked")

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/SourceCreatingTransformer.java

@@ -45,7 +45,7 @@ public class SourceCreatingTransformer implements MessageTransformer {
 
 	public Message<?> transform(Message<?> message) {
 		Source source = this.sourceFactory.getSourceForMessage(message);
-		return new GenericMessage<Source>(source, message.getHeader());
+		return new GenericMessage<Source>(source, message.getHeaders());
 	}
 
 }

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/XmlPayloadMarshallingTransformer.java

@@ -74,7 +74,7 @@ public class XmlPayloadMarshallingTransformer implements MessageTransformer {
 		if (transformedPayload == null) {
 			throw new MessageHandlingException(message, "failed to transform payload");
 		}
-		return new GenericMessage(transformedPayload, message.getHeader());
+		return new GenericMessage(transformedPayload, message.getHeaders());
 	}
 
 }

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/XmlPayloadUnmarshallingTransformer.java

@@ -69,7 +69,7 @@ public class XmlPayloadUnmarshallingTransformer implements MessageTransformer {
 
 		try {
 			Object unmarshalled = this.unmarshaller.unmarshal(source);
-			return new GenericMessage(unmarshalled, message.getHeader());
+			return new GenericMessage(unmarshalled, message.getHeaders());
 		}
 		catch (IOException e) {
 			throw new MessagingException(message, "Failed to unamrshal payload", e);

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/transformer/XsltPayloadTransformer.java

@@ -77,7 +77,7 @@ public class XsltPayloadTransformer implements MessageTransformer {
 	protected Message<Result> transformSource(Message message, Source source) throws TransformerException {
 		Result result = resultFactory.getNewResult(message);
 		this.templates.newTransformer().transform(source, result);
-		return new GenericMessage<Result>(result, message.getHeader());
+		return new GenericMessage<Result>(result, message.getHeaders());
 	}
 
 	public void setSourceFactory(SourceFactory sourceFactory) {