Small Stax fixes.

org.springframework.core/src/main/java/org/springframework/util/xml/StaxEventContentHandler.java

 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 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.
@@ -32,6 +32,7 @@ import javax.xml.stream.util.XMLEventConsumer;
 import org.xml.sax.Attributes;
 import org.xml.sax.Locator;
 
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -58,6 +59,7 @@ class StaxEventContentHandler extends AbstractStaxContentHandler {
 	 * @param consumer the consumer to write events to
 	 */
 	StaxEventContentHandler(XMLEventConsumer consumer) {
+		Assert.notNull(consumer, "'consumer' must not be null");
 		eventFactory = XMLEventFactory.newInstance();
 		eventConsumer = consumer;
 	}

org.springframework.core/src/main/java/org/springframework/util/xml/StaxEventXMLReader.java

@@ -43,6 +43,7 @@ import org.xml.sax.SAXException;
 import org.xml.sax.ext.Locator2;
 import org.xml.sax.helpers.AttributesImpl;
 
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -78,6 +79,7 @@ class StaxEventXMLReader extends AbstractStaxXMLReader {
 	 * @throws IllegalStateException if the reader is not at the start of a document or element
 	 */
 	StaxEventXMLReader(XMLEventReader reader) {
+		Assert.notNull(reader, "'reader' must not be null");
 		try {
 			XMLEvent event = reader.peek();
 			if (event != null && !(event.isStartDocument() || event.isStartElement())) {

org.springframework.core/src/main/java/org/springframework/util/xml/StaxStreamContentHandler.java

 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 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.
@@ -24,6 +24,7 @@ import javax.xml.stream.XMLStreamWriter;
 import org.xml.sax.Attributes;
 import org.xml.sax.Locator;
 
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -44,6 +45,7 @@ class StaxStreamContentHandler extends AbstractStaxContentHandler {
 	 * @param streamWriter the stream writer to write to
 	 */
 	StaxStreamContentHandler(XMLStreamWriter streamWriter) {
+		Assert.notNull(streamWriter, "'streamWriter' must not be null");
 		this.streamWriter = streamWriter;
 	}
 

org.springframework.core/src/main/java/org/springframework/util/xml/StaxStreamXMLReader.java

@@ -27,6 +27,7 @@ import org.xml.sax.SAXException;
 import org.xml.sax.ext.Locator2;
 import org.xml.sax.helpers.AttributesImpl;
 
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -60,6 +61,7 @@ class StaxStreamXMLReader extends AbstractStaxXMLReader {
 	 * @throws IllegalStateException if the reader is not at the start of a document or element
 	 */
 	StaxStreamXMLReader(XMLStreamReader reader) {
+		Assert.notNull(reader, "'reader' must not be null");
 		int event = reader.getEventType();
 		if (!(event == XMLStreamConstants.START_DOCUMENT || event == XMLStreamConstants.START_ELEMENT)) {
 			throw new IllegalStateException("XMLEventReader not at start of document or element");