Are you saying that you've tried to call two mappings, one with an associated actionForm and another without, and when calling action without associated form you get a valid reference to a form? Are you sure? Because it does not sound right, you should get null.
On 5/3/06, Kyle W. Cartmell <[EMAIL PROTECTED]> wrote:
So in a Struts web application if I supply two mappings for a single action, one that has a form and one that does not, and I call the one with the form and then a few seconds later call the one without, the form parameter to the execute method is not null on the second call. I don't understand why this would be so... Michael Jouravlev wrote: > On 5/3/06, Kyle W. Cartmell <[EMAIL PROTECTED]> wrote: >> I did some tinkering and found that even though my setup action is >> indeed associated with a form bean, and my reset method is defined and >> sets my values to null, when I return to an action from a validation >> failure or forwarded from another action, the form that I originally >> used to populate the data on that page is present and intact. >> >> 1. Is it reasonable to simply make use of this mechanic to allow this >> data to persist? > > How many forms do you have: one or two? If two, do they have > properties with the same names? If I remember correctly, this should > work somewhat like this: > > * You submit an HTML form to a submit action, well, actually to an > action mapping > * If actionform is defined for the mapping, it is initialized. That > means, that if it has request scope, it is created. If it has session > scope it is usually reused (this is not guaranteed, but I've yet to > encounter the situation when session-scoped form was not reused). > * reset() is called on form > * form is populated from request parameters > * if "validate" attribute of the action mapping is set to true, > validate() is called > * if validate() returns non-empty object and you have "input" > attribute set, then control is forwarded to the location defined in > the "input". (Hmm, what happens if you have validate="true" but do not > have "input" attribute?) By the way, it is possible to redirect to > "input" location instead of forwarding, but this is done globally for > all mappings in the config file. > * If you do a regular forward using "input" attribute, the > request/response sequence has not been finished yet, so all objects > that were created when you submitted the request, are still there, > including request-scoped actionform and request object itself. So, if > you forward to a regular JSP page, you can pull data from the > actionform or from request object. > * Now, the fun part. If you forward to a setup action, then Struts > will look for an actionform associated with this mapping, and will > call reset() on it, then it will try to populate it from the request > object, then it will call validate() if you have validate="true". So, > if you forward to a setup action and you have changed content of the > actionform, you should either NOT associate a form with an action. > Because otherwise your changes to actionform fields will be > overwritted from the request object. Does it make sense? ;-) > >> 2. I find that I am shocked by some astounding discovery regarding >> Struts functionallity, and I have gone through all of the documentation >> on the website, can anyone direct me toward comprehensive (or as close >> as possible) documentation of Struts internals in hopes that I can stop >> posting silly questions here and not have to resort to reading source? > > I think that it all clears when you understand how scoped objects are > managed, and how the request/response cycle works. The key here is > that Struts runs its portion of request/response code whenever you > call an action mapping, even if you make a server-side forward. > > I wrote a small article on that topic [1]. It is not perfect and, > frankly, needs a rewrite (I introduced my own names to some of the > action/form combinations), I would do some things differently. But > some sections of it are still valuable. Take a look at "Two actions, > one form" and "Two actions, two forms" sections. Currently I prefer to > use only one actionform and two action classes (input and render) for > one web resource. > > Oh yeah, and as the article says, use the same scope if you use the > same form name :-) Otherwise you'll get some funny results. > > Michael. > > [1] > http://www.theserverside.com/articles/article.tss?l=StrutsActionMapping -- Kyle W. Cartmell Sr. Software Developer LAP Holdings, LLC dba First Finance Phone: (480) 222-0050 Toll Free: (800) 355-3135 [EMAIL PROTECTED] www.efirstfinance.com
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