Correction to previous post: I can only imagine having a JPAConversational scope built around a Custom RequestCycle or is there other things involved on this?
On Fri, Apr 15, 2011 at 8:37 PM, Juan Carlos Garcia <[email protected]>wrote: > @Igor, this is really interesting. I can only imagine having a > JPAConversational scope built around a Custom RequestCycle or is there could > be other thing involved on this? > > > On Fri, Apr 15, 2011 at 11:58 AM, Igor Vaynberg-2 [via Apache Wicket] < > [email protected]> wrote: > >> we use conversations a lot, mostly for keeping a jpa session open >> across requests. >> >> imagine the following situation: >> >> you have a person entity that has a one to many relation to an address >> entity and address has a many to one relationship with a city. you >> have a page where the user can add multiple addresses to the person, >> but the requirement is that none of the addresses are saved until the >> user presses the save button. should the user add two addresses and >> then press cancel none of the addresses are safe. this is a general >> "atomic action across multiple requests" example. >> >> how do you do this with models? even if your entities are >> serializable, which they probably should not be, you have a problem >> with address->city linkage because it will become stale across >> requests where each request has its own jpa session. so the easiest >> but messiest way is to reserve to using some sort of dto to keep track >> of added addresses, remove addresses, edited addresses, etc. the big >> problem with the dto is now your components have to work with a dto as >> well. eg you have to support add(new AddressEditor("foo", address)) >> and add(new AddressEditor("foo", addressDto));, and no - they cant >> implement some interface unless the address dto knows how to lazy load >> city from jpa session,etc, etc. look how long it took just to describe >> this. >> >> using a conversation workflows page or pages like this are *no >> different* then others. we store our jpa session in conversation. when >> the page loads we mark conversation as persistent so it will survive >> across requests and is passed from page to page - unless user >> navigates to a bookmarkable page. we also set the jpa session to flush >> mode manual. all code works like it normally would, with entity >> models. it doesnt know that it is working across requests. our entity >> models are smart enough to know that until the entity has an database >> id it should be stored in a special conversational store that is >> basically a map:uuid->object. when the user presses save we flush the >> session and all of their changes are persisted in a transaction. when >> the user presses cancel we clear the session and close the converation >> - which undoes all their changes. this has the added bonus of the >> session acting as a database cache for the workflow. >> >> -igor >> >> >> On Fri, Apr 15, 2011 at 12:45 AM, Carl-Eric Menzel >> <[hidden >> email]<http://user/SendEmail.jtp?type=node&node=3452263&i=0&by-user=t>> >> wrote: >> >> > I have to admit I've never quite understood the need for seam-style >> > conversations in Wicket. Whenever I need to do some kind of >> > defined workflow, I simply use appropriate IModel instances that get >> > passed around between the participating components. What is the use >> > case of using a conversation construct over models? >> > >> > Carl-Eric >> > www.wicketbuch.de >> > >> > On Thu, 14 Apr 2011 23:14:14 -0700 >> > Igor Vaynberg <[hidden >> > email]<http://user/SendEmail.jtp?type=node&node=3452263&i=1&by-user=t>> >> wrote: >> > >> >> seam-wicket provides a full implementation. >> >> >> >> if you want "clean" you can build it yourself, its not too difficult. >> >> subclass session and inside put a map of <conversationId,conversation> >> >> and manage that map however you see fit in your app. >> >> >> >> -igor >> >> >> >> >> >> On Thu, Apr 14, 2011 at 10:55 PM, YK <[hidden >> >> email]<http://user/SendEmail.jtp?type=node&node=3452263&i=2&by-user=t>> >> wrote: >> >> > Are you planning to develop a conversation/workspace module ? >> >> > >> >> > What I mean by "conversation" is a "session portion" or >> >> > manageable/controllable "mini" session >> >> > that can be started and finished programmatically. >> >> > >> >> > This allows building multi-step programs and/or workflow and permits >> >> > generally memory (objects in session) management. >> >> > >> >> > I know that wicket-seam provides this (partially) but what I would >> >> > like to know is : could we have a "pure" >> >> > wicket one ? and if it is feasible. >> >> > >> >> > >> >> > Thanks >> >> > >> >> > -- >> >> > View this message in context: >> >> > >> http://apache-wicket.1842946.n4.nabble.com/wicket-conversation-workspace-tp3451294p3451294.html<http://apache-wicket.1842946.n4.nabble.com/wicket-conversation-workspace-tp3451294p3451294.html?by-user=t> >> >> > Sent from the Forum for Wicket Core developers mailing list archive >> >> > at Nabble.com. >> >> > >> > >> > >> >> >> ------------------------------ >> If you reply to this email, your message will be added to the discussion >> below: >> >> http://apache-wicket.1842946.n4.nabble.com/wicket-conversation-workspace-tp3451294p3452263.html >> To start a new topic under Apache Wicket, email >> [email protected] >> To unsubscribe from Apache Wicket, click >> here<http://apache-wicket.1842946.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=1842946&code=amNnYXJjaWFtQGdtYWlsLmNvbXwxODQyOTQ2fDEyNTYxMzc3ODY=>. >> >> > > > > -- > Sincerely, > JC (http://www.linkedin.com/in/jcgarciam) > --Anyone who has never made a mistake has never tried anything new.-- > > > -- -- JC -- View this message in context: http://apache-wicket.1842946.n4.nabble.com/wicket-conversation-workspace-tp3451294p3453215.html Sent from the Forum for Wicket Core developers mailing list archive at Nabble.com.
