----- Original Message -----
From: "Wagoner, Mark" <[EMAIL PROTECTED]>
To: "'Tomcat Users List'" <[EMAIL PROTECTED]>
Sent: Tuesday, March 26, 2002 2:12 PM
Subject: RE: AW: Multiple users share java bean?
> Are you sure you really want independent instances of the bean, or just
the
> ability to keep the variable values separate by user? If it is the
latter,
> then just use local variables in your bean methods.
>
It seems that couldn't work. The value of such variables can be updated by
another user's when there are two or more users calling the same java bean
almost at the same time. Here is my main work. First jsp write uname (when a
user login the website, there is a user name "uname") to the bean and
activate it, and get the result or save it to the database.
Jsp file:
<jsp:useBean id="mb" class="mybean.test" scope="page" />
???How about the scope value? session or request or page?
<jsp:setProperty name="mb" property="uname" value="<%=loginname) %>"/>
<p>The result is:
<%= mb.test() %></p>
Bean code:
public class test
{
String uname= "";
public synchronized int test()
{
int real=0;
int eventCounter=0;
int numEvents;
// connect to the database and get the numEvents according to the
uname.
.........;
while(eventCounter<=numEvents)
{
real=eventCounter;
// wait for 0.01 second
try{wait(10);}
catch(InterruptedException e){};
eventCounter++;
}
return real;
}
public synchronized void setUname(String sec)
{
uname= sec;
}
}
For user1, numEvents=100; and user2, it's 120. So I want to run them at the
same time, and hope to get resuls 100 and 120 respectively. But in fact I
got both 100 or 120. Have any idea? If my description is not clear, tell me
please.
> -----Original Message-----
> From: Chenming Zhao [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, March 26, 2002 2:06 PM
> To: Tomcat Users List
> Subject: Re: AW: Multiple users share java bean?
>
>
> What's the meaning of JMS? I'm not sure my problem is just what you said.
I
> want to get independent instance or the same bean for each user. So they
can
> work independently, and won't influence with each other. Thanks.
>
> ----- Original Message -----
> From: "peter lin" <[EMAIL PROTECTED]>
> To: "Tomcat Users List" <[EMAIL PROTECTED]>
> Sent: Tuesday, March 26, 2002 1:32 PM
> Subject: Re: AW: Multiple users share java bean?
>
>
> >
> > One common technique to solve this is to use JMS. All beans that are
> > instances of the same user listen to the same topic. when one instance
> > of the user's bean is updated, the other instances are notified. Each
> > bean then goes to the database to refresh itself.
> >
> > peter lin
> >
> >
> > Chenming Zhao wrote:
> > >
> > > In fact, it's a good and difficult topic. Now I haven't still
understood
> it
> > > completely. I have a question about my application.
> > >
> > > I describe the work what I need to finish.
> > > First the jsp file gets a user name, then pass it to java bean. And
the
> bean
> > > get some values from the database accoding to the user name, then get
a
> > > result and save it to database. The idea of synchronized objects
cannot
> > > work. I want to acitvate independent instance of java bean for any
user.
> How
> > > can I do? Is there any good book or material? Or maybe you can show me
> some
> > > simple example?
> > >
> > > Thanks.
> > >
> > > --
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> >
>
>
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