consistent update of HeaderValueHolder class

org.springframework.web.servlet/src/test/java/org/springframework/mock/web/HeaderValueHolder.java

 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -71,6 +71,10 @@ class HeaderValueHolder {
 		return (!this.values.isEmpty() ? this.values.get(0) : null);
 	}
 
+	public String getStringValue() {
+		return (!this.values.isEmpty() ? this.values.get(0).toString() : null);
+	}
+
 
 	/**
 	 * Find a HeaderValueHolder by name, ignoring casing.

org.springframework.web/src/test/java/org/springframework/mock/web/HeaderValueHolder.java

 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -71,6 +71,10 @@ class HeaderValueHolder {
 		return (!this.values.isEmpty() ? this.values.get(0) : null);
 	}
 
+	public String getStringValue() {
+		return (!this.values.isEmpty() ? this.values.get(0).toString() : null);
+	}
+
 
 	/**
 	 * Find a HeaderValueHolder by name, ignoring casing.