>From this description, it seems to me like you just need the regular
<jsp:useBean> tag. If your page contains this (somewhere near the top):
<jsp:useBean id="myBean" class="in.co.tcs.delhi.MyBean" scope="session">
... your bean initialization code goes here...
</jsp:useBean>
Then you'll have a session bean that is (a) created and initialised the
first time it is referenced, and (b) only created once (per session). I
think that is what you wanted, right?
Hope this helps.
--
Martin Cooper
Tumbleweed Communications
----- Original Message -----
From: "ShriKant Vashishtha" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, October 11, 2000 11:17 PM
Subject: Re: Singleton Pattern and JSP
> Hi,
>
> Actually I would like to clarify my requirement. The screens are related
to e-com
> selection criteria. There are so many combobox in any of those screens for
which
> the data needs to be fetched from the database. But the same data can be
reused in
> other screens too. For example if I need country list for selection in one
of the
> screen, the same list is used for selection in other screens too. But
these screens
> may be related or may not be. So what I want, the first time I need the
country
> list, I will be fetching those details from the data base and will store
in a bean
> to avoid the traffic to the database. For subsequent requests, the list
will be
> fetched from the bean only. Similarly whenever any other list is needed,
it will be
> fetched from the database and will be stored in the same bean.
>
> Now I want to create only one instance of the bean throughout the session
which
> could be reused in other screens too. That's why I thought of using
Singleton
> pattern. But at present I am not clear, whether the bean instance which is
being
> created in one of the JSP could be used in other JSPs too, ie if Singleton
instance
> is created in one of the screen, it should not be created in subsequent
screens.
>
> Please suggest.
> -ShriKant
>
> Rathna wrote:
>
> > hi shri,
> >
> > The bean Object access scope will be limited to the page
> > where it has been instantiated regardless of the bean scope.
> >
> > But when you instantiate the object in the subsequent page
> > the creation of the object will be decided upon the scope
> > of the object.for example you are trying to create the object
> > again which is in the scope 'session' then you will get the
> > same reference.
> >
> > In case of singleton ,provide a static method to get the
> > object of the class and have the implementation as follows,
> >
> > create the object of it's own when it does not exists in
> > the JVM and return the reference.Make sure you are having
> > the constructor as private.
> >
> > Then call the static method of the class to get the reference
> > instead of using usebean tag.
> >
> > hope this helps,
> >
> > with regards,
> > rathna.
> >
> > >>Hi,
> >
> > I have a requirement where I have to store the data in a persistent java
> > class and then whenever user requires it he can use it. So per session I
> > want to create only one instance of the class which will be used in
> > different JSPs.
> >
> > I want to use Singleton pattern to maintain only one instance per
> > session. So in any JSP if user wants to create another instance of the
> > class, the same instance should be returned to the user.
> >
> > My doubt is, whether the scope of the class object instantiated in a JSP
> > will be limited to that page only or class object can be accessed if
> > exists, in subsequent pages also.
> >
> > Please clarify.
> > Thanks in advance
> >
> >
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