Here's "Example 3" where a ClientResponseFilter and a ReaderInterceptor
work beautifully together. This also shows why you might want to allow
a ReaderInterceptor the ability to return a java.lang.Object.
-- Example 3: Client-side Caching --
Flow:
0. Application code calls:
Response response = target.request().get();
1. ClientRequestFilter find that the request URL is cached, but the
cache may have expired
2. ClientRequestFilter adds If-None-Match, If-Modified-Since headers and
does a conditional GET
3. ClientResponseFilter processes the response.
4. ClientResponseFilter finds that cached entity is still valid.
5. ClientResponseFilter updates cache entry with any new Cache-Control
metadata
6. ClientResponseFilter sets the response InputStream to the raw
representation of the resource (a gzipped XML document in this case)
6. ClientResponseFilter adds Content-Type header and changes Response
code to 200.
7. ClientResponseFilter adds the cache entry to the its context's
property map so that the ReaderInterceptor can reference it.
7. Application code calls:
Foo foo = response.getEntity(Foo.class);
8. Caching ReaderInterceptor pulls the cache entry from context property map
9. Caching ReaderInterceptor asks the cache entry if it has ever
unmarshalled Foo.class. If it has, it returns it. Done. *THIS IS AN
EXAMPLE OF a READER INTERCEPTOR CHANGING THE ENTITY*. In this case, it
totally bypasses the MBR.
10. Caching ReaderInterceptor just proceeds to the next ReaderInterceptor
11. GZIP ReaderInterceptor sees that the cached InputStream is gzip
encoded by seeing a Content-Encoding header. It wraps the InputStream.
12. MBR unmarshalls the GZIPPED XML Document.
--
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com