Hi
Let me specify a similar (more general) scenario:
Suposse a servlet-based application without several entry points.
There isn't an unique initial point, so you can't initialize the DBPool, or others
common resources,
in a particular servlet. Each servlet is able to manage the users by some kind of
session management,
or authentication.
In this context, we use the following aproach to solve the problem (DBPool
initialization).
The DBPool class, has a Hashtable with the active pools.
This class has a methods like:
public static Connection getConnection(String user, String password){
}
or more sophisticated:
public static Connection getConnection(String user, String password, String
jdbc_driver, int number_of_connections)
The returned connection is binded to the proper DBPool by another Hashtable, so
may be released with
a method like:
public static void release(Connection conn){
// which DBPool is binded with this connection?
DBPool pool = hash_connections_dbpools.get(conn);
// mark the connection as ready for a new request
pool.hash_locked.remove(conn):
pool.hash_unlocked.put(conn, new Long(System.currentTimeMillis())):
}
(The currentTimeMillis can be used by a cleaner thread that release connections
after a long time,
as a prevention from unreleased connections)
When a servlet (or whatever) claim for a connection of a pool, the DBPool class
checks if
there are a created pool with the specified
user/password/jdbc_driver/number_of_connetcions...
and is created if necessary.
Then return an available connection of that pool.
You can also specify a default number of connections, JDBC driver, ..., so the
client doesn't see the pool,
just a connection (the goal here is encapsulation).
In this way there is no need for a ServletContext, or preloading servlets.
Any idea are wellcome.
Bing Zhang wrote:
> I just found out that servletrunner can not preload a servlet. I am using
> the servletrunner to test my application. If you only use servletrunner to
> test your application, the way to get around is in your calling code you
> call the servlet you want to preload first.
>
> Apache/Jserv has the capability to preload the servlet.
>
> Bing
>
> At 12:06 PM 6/10/99 +0200, you wrote:
> >How do you preload a servlet ??? (I'm using the jsdk2.1 servletrunner)
> >
> >> How about construct a faceless servlet,i.e. GenericSerlet, preload it and
> >> initialize the connection pool and store it as a static member of a class.
> >> The subsequent servlet just call a method of this class, be it static or
> >> non static. In this case you do not need ServletContext.
> >>
> >> Bing
> >>
> >> At 08:41 PM 6/9/99 +0100, you wrote:
> >>>What about the following:
> >>>
> >>>The first time DbServlet is called, get the ServletContext and assign it to
> >>>a static variable. Also create a public static method in DbServlet to
> return
> >>>the ServletContext. Any class could then retrieve the SessionContext.
> >>>
> >>>Not sure if this is the best way of doing it, but hope it helps.
> >>>
> >>>Stephen Baishya
> >>>
> >>>----- Original Message -----
> >>>From: tmueller <[EMAIL PROTECTED]>
> >>>To: <[EMAIL PROTECTED]>
> >>>Sent: Tuesday, June 08, 1999 10:13 PM
> >>>Subject: Connection Pooling Servlet
> >>>
> >>>
> >>>> Hello all,
> >>>>
> >>>> Im writing a servlet (DbServlet) that uses the DbConnectionBroker as
> >>>> explained in chapter 9 pg. 266 of the Jason Hunter (O'Reilly) book that
> >>>will
> >>>> hand off connection objects.
> >>>>
> >>>> The problem is that the classes of another servlet cannot use
> >>>> getServletContext() to get the reference to the DbServlet
> >>>> since the classes have no servlet context of thier own.
> >>>>
> >>>> So my question is : Is there a way to get to the DbServlet with out
> having
> >>>> to hand out the ServletContext to every class
> >>>> and the classes they use?
> >>>>
> >>>> Thanks in advance.
--
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Manuel Hurtado Sanchez
Telefonica Data
Phone: +34 917548650
Fax: +34 917548692
Julian Camarillo,6
28037 Madrid, Spain.
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