I have a couple subsystems (data access subsystem,
authorization, logging, etc..) that I initialize by extending
ActionServlet. It would be nice to not have to extend
ActionServlet and initialize each extension/subsystem manually.
One approach would be to trigger initialization of the
services off of the struts-config.xml.
For each service you want to use, you'd just list it in
your struts-config.xml:
<extension class="org.apache.strutsx.some.Extension"/>.
Another issue is how to configure these extensions/subsystems.
Right now I'm using the Digester class to configure
my subsystems off of seperate config files.
Each subsystem having its own configuration file
is simple (e.g. each config file can have a separate
format and DTD, and each subsystem can register
its own configuration rules with the Digester),
but you end up having to manage
a bunch of configuration files instead of just one.
By the way, thanks to whoever worked on the Digester -
very useful and a breeze to use.
--Ron
David Winterfeldt wrote:
> It might be nice if there was a way to register an
> interface with the ActionServlet in the config file
> for it to initialize a service. All the
> ValidatorServlet I made does is parse the xml file
> with the Digester and put an object into application
> scope. If a class could be registered, then a servlet
> wouldn't hang around for no reason and it wouldn't
> need to be defined in the web.xml. And it sounds like
> a lot of people extend the ActionServlet just to
> initialize resources on startup.
>
> David
>
> --- Ted Husted <[EMAIL PROTECTED]> wrote:
> > I agree that most extensions would be best written
> > as independant
> > servlets that plug into the application alongside
> > the Struts
> > ActionServlet. Though, I'm not sure they would need
> > to register with the
> > ActionServlet to access other parts of the
> > framework.
> >
> > I haven't worked with the Digester directly, but
> > most of the other
> > Struts services are already exposed through the
> > application context.
> > Custom tags, for example, already access the Action
> > Mappings this way.
> > So any other servlet in the application (since
> > that's all JSP's are)
> > should be able to do the same.
> >
> > Another example is the Generic Connection Pool. The
> > datasource is
> > exposed through the application context and other
> > services, like the
> > TagLibs JDBC tags, can use the pool without knowing
> > anything about
> > Struts (or Struts knowing anything about them).
> >
> > So I would suggest that if there are other services
> > that an extension
> > needs to share that we expose them through the
> > Application context.
> >
> > Oleg V Alexeev wrote:
> >
> > > To support flexible extensions mechanism for
> > struts there are can be
> > > made some additions to the core structure of the
> > framework -
> > >
> > > 1. Add ability to register components or external
> > servlets (at
> > > application level) via struts-config file.
> > > 2. Give such external components or servlets
> > ability to use action
> > > mappings database from ActionServlet.
> > > 3. Extend core API of struts to support pluggable
> > extensions - for
> > > example use event model or direct calls via
> > registrations in action
> > > mappiongs database.
> > >
> > > The best way for my mind is to write external
> > servlets, register it in
> > > struts ActionServlet and use it as external
> > services. This approach
> > > can be useful in case of mutliple ActionServlet
> > instances in one
> > > application - every ActionServlet subscribe to use
> > and uses some
> > > amount of external services.
>
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