Preserve comments when using JibxMarshaller

Prior to this commit, JibxMarshaller used a SAX ContentHandler to
marshal to StAX XMLEventWriters, which inadvertently resulted in the
deletion of XML comments.

After this commit, JibxMarshaller adapts the XMLEventWriter into an
XMLStreamWriter and comments are preserved.

Issue: SPR-9768

spring-core/src/main/java/org/springframework/util/xml/StaxUtils.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.
@@ -309,6 +309,15 @@ public static XMLStreamReader createEventStreamReader(XMLEventReader eventReader
 		return new XMLEventStreamReader(eventReader);
 	}
 
+	/**
+	 * Return a {@link XMLStreamWriter} that writes to a {@link XMLEventWriter}.
+	 * @return a stream writer that writes to an event writer
+	 * @since 3.2
+	 */
+	public static XMLStreamWriter createEventStreamWriter(XMLEventWriter eventWriter) {
+		return new XMLEventStreamWriter(eventWriter, XMLEventFactory.newFactory());
+	}
+
 	/**
 	 * Return a {@link XMLStreamWriter} that writes to a {@link XMLEventWriter}.
 	 * @return a stream writer that writes to an event writer

spring-core/src/main/java/org/springframework/util/xml/XMLEventStreamWriter.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.
@@ -193,7 +193,7 @@ public void close() throws XMLStreamException {
 
 	private void writeStartElement(StartElement startElement) throws XMLStreamException {
 		eventWriter.add(startElement);
-		endElements.add(eventFactory.createEndElement(startElement.getName(), null));
+		endElements.add(eventFactory.createEndElement(startElement.getName(), startElement.getNamespaces()));
 	}
 
 	private void writeNamespace(Namespace namespace) throws XMLStreamException {

spring-core/src/test/java/org/springframework/util/xml/XMLEventStreamWriterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 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.
@@ -29,8 +29,7 @@
 public class XMLEventStreamWriterTests {
 
 	private static final String XML =
-			"<?pi content?><root xmlns='namespace'><prefix:child xmlns:prefix='namespace2'>content</prefix:child></root>"
-			;
+			"<?pi content?><root xmlns='namespace'><prefix:child xmlns:prefix='namespace2'><!--comment-->content</prefix:child></root>";
 
 	private XMLEventStreamWriter streamWriter;
 
@@ -52,6 +51,7 @@ public void write() throws Exception {
 		streamWriter.writeDefaultNamespace("namespace");
 		streamWriter.writeStartElement("prefix", "child", "namespace2");
 		streamWriter.writeNamespace("prefix", "namespace2");
+		streamWriter.writeComment("comment");
 		streamWriter.writeCharacters("content");
 		streamWriter.writeEndElement();
 		streamWriter.writeEndElement();
@@ -61,4 +61,4 @@ public void write() throws Exception {
 	}
 
 
-}
+}

spring-oxm/src/main/java/org/springframework/oxm/jibx/JibxMarshaller.java

@@ -338,8 +338,8 @@ private void transformAndMarshal(Object graph, Result result) throws IOException
 
 	@Override
 	protected void marshalXmlEventWriter(Object graph, XMLEventWriter eventWriter) {
-		ContentHandler contentHandler = StaxUtils.createContentHandler(eventWriter);
-		marshalSaxHandlers(graph, contentHandler, null);
+		XMLStreamWriter streamWriter = StaxUtils.createEventStreamWriter(eventWriter);
+		marshalXmlStreamWriter(graph, streamWriter);
 	}