On 1/30/12 3:15 PM, Greg Wilkins wrote:
>
> currently the spec says in 6.2.1 - 4
>
> /The filter may invoke the next entity in the filter chain. The next
> entity may be
> another filter, or if the filter making the invocation is the last
> filter configured in the
> deployment descriptor for this chain, the next entity is the target
> Web resource. The
> invocation of the next entity is effected by calling the doFilter
> method on the
> FilterChain object, and passing in the request and response with which
> it was
> called or passing in wrapped versions it may have created.
> The filter chain’s implementation of the doFilter method, provided by the
> container, must locate the next entity in the filter chain and invoke
> its doFilter
> method, passing in the appropriate request and response objects.
> /
>
>
> This strongly indicates that it is the thread calling doFilter that
> invokes the next element of the chain, be that a filter or
> servlet. Also it is a very common pattern to use try{}finally{}
> in filters to allocate and free resources, so it is essential to keep
> the invocation chain intact.
>
> Thus if we clarify this, is must be to say:
>
> The service method is required to run in the same thread as all
> filters that apply to the servlet.
+1
>
>
> regards
>
>
>
>
> On 31 January 2012 08:08, Shing Wai Chan <shing.wai.chan_at_oracle.com
> <mailto:shing.wai.chan_at_oracle.com>> wrote:
>
> In an internal platform discussion, there is a question of whether
> all filters need to be run in the same thread as in servlets.
> In Section 6.2 of Servlet 3.0, there is a description on how
> filters work.
> There is "no" explicit requirement that the filters need to be run
> in the same thread.
> Is it a tacit assumption?
>
> We propose that the spec ought to say either:
>
> - The service method is required to run in the same thread as all
> filters
> that apply to the servlet.
>
> or
>
> - The service method is **not** required to run in the same thread
> as filters
> that apply to the servlet, and filters should not depend on sharing
> thread local data with the servlet.
>
>
> Shing Wai Chan
>
>