ETag in Spring (ShallowEtagHeaderFilter)

Question

Hi guys,

I've followed http://static.springsource.org/spring/docs/3.0.2.RELEASE/spring-framework-reference/html/mvc.html#mvc-etag and put ShallowEtagHeaderFilter in my web.xml like this:

<filter> 
  <filter-name>etagFilter</filter-name> 
  <filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class> 
</filter> 

<filter-mapping> 
  <filter-name>etagFilter</filter-name> 
  <servlet-name>myServlet</servlet-name>
  <!-- I've even tried <url-pattern>/*</url-pattern>  -->
</filter-mapping> 

But whenever I load my pages, I don't get any etag headers in my response. Any suggestions as to what might be going on? Is there any kind of ordering my filters should have? (I'm also using OpenSessionInViewFilter and DelegatingFilterProxy

Cheers

Nik