What's a DVO?
On Thu, Jun 13, 2002 at 12:56:38PM +0530, Vikram Goyal01 wrote: > >Also, how do we deal with the situation where we need to build up > >information over a series of requests before we can actually save it or do > >something with it (ie: wizards etc...) > > In reply to an earlier post regarding something similar, my idea is to encapsulate >the information required for the wizard in a DVO and not a form bean. This helps keep >form beans in request and thus enables thread safety. On each page of the wizard, you >update the DVO with the values in the form bean and only keep the DVO in session. > I agree with Craig when he says that the form bean should only be kept in request >scope. > > Rgs > Vikram > > > -----Original Message----- > From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]] > Sent: Thursday, June 13, 2002 14:17 > To: Struts Users Mailing List > Subject: Re: thread safety > > > > > On Wed, 12 Jun 2002, Noah Levitt wrote: > > > Date: Wed, 12 Jun 2002 19:57:39 -0400 > > From: Noah Levitt <[EMAIL PROTECTED]> > > Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]> > > To: [EMAIL PROTECTED] > > Subject: thread safety > > > > Hello struts users, > > > > The issue of thread safety bugs me. It seems as though it is > > standard practice to write servlets thread-*unsafely*. The > > odds of it ever being a problem are slim, but still. > > > > It seems to me that form bean setters (and probably getters) > > should be synchronized. I found the following two quotes > > from Craig McClanahan. To me, they seem contradictory. > > However, even if we use the "that's going to be real > > unusual" standard, shouldn't we synchronize setters, since, > > in theory, it's the only thread-safe thing to do? > > > > http://archive.covalent.net/jakarta/struts-dev/2000/06/0117.xml > > > > Craig: > > "For the form beans, you are creating them in a particular > > user's session. If the user does two submits to the same > > form at the same time you might have overlapping setXxx > > method calls going on, but that's going to be real > > unusual." > > > > http://archive.covalent.net/jakarta/struts-user/2001/03/0013.xml > > > > Craig: > > "It is surprisingly easy to have multiple requests active > > at the same time for the same session." > > > > The simplest way to avoid this whole set of problems is to use request > scope for your form beans. Then, the container guarantees that only one > thread can access these beans, so you don't need to be concerned at all > about thread safety in them. > > Following this advice will also be beneficial, in general, to the > scalability of your application -- because the server will not need to > store the form beans in memory "in between" requests. > > Craig > > > > Noah > > > > > > -- > > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > > > > > > > -- > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
