"Steven W. Rock" wrote:
> Hi All,
>
> Thanks for your thoughtful and enlightening threads of discussion on the
> Model 2 architecture. I have been building a web site using Servlets, beans,
> java classes and JSP based on this model. The one question I have which
> seems to be missing from these discussions is where do I store the
> Connection Pool? My current thoughts are to initialize the connection pool
> in the controller servlet init() function, create the Pool as a Singleton,
> then any java class at the persistence level that needs a connection just to
> call ConnectionPool.getInstance(). Is this what most people are doing? The
> other option I suppose is to pass a connection through the Java Bean Action
> class, down through the persistence java classes.
>
One option to consider is storing the connection pool as a servlet context
attribute. Go ahead and create it in the init() method of your controller servlet,
then execute:
ConnectionPool pool = ...;
getServletContext().setAttribute("pool", pool);
Now, if you've read my suggestions on the method signature of the perform method in
action classes, you will note that I pass the servlet itself as an argument:
public interface Action {
public void perform(HttpServlet servlet,
HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException;
}
One of the main reasons I do this is so that action classes have access to the
resources of the servlet context. In particular, from within the perform() method
of an action class, I can call:
ConnectionPool pool = (ConnectionPool)
servlet.getServletContext().getAttribute("pool");
Connection conn = pool.getConnection();
and pass the connection on to business logic beans that need it.
>
> In a similar vein, how do people handle logging. I wish to have one logger
> class accessible by all classes in my application. This includes the
> Servlets, beans and regular java classes.
>
I use the same technique for other application-wide shared resources as I described
for connection pools above -- store them in the servlet context attributes. As an
added bonus, I can even refer to these resources in a JSP page:
<jsp:useBean id="logger" class="com.mycompany.mypackage.MyLogger"
scope="application"/>
or in an action class:
MyLogger logger = (MyLogger)
servlet.getServletContext().getAttribute("logger");
> I've programmed with a proprietary Application Server Web Objects, that had
> one Application class that was accusable by all other classes in the
> application. Here I stored the logging, and any other global services. How
> would I handle this with Servlets, JSP, bean Model 2 architecture.
>
That's pretty much what servlet context attributes are for.
>
> Thanks for your time in this matter.
>
> -Steven Rock
> hitmusic.com - choose and watch music videos of today's top hits.
>
Craig McClanahan
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