That forum thread is several years old and I don't think it applies anymore. For one, it talks about using components in a <c:forEach> loop. I haven't been able to use an EL expression to set an id. I get an error when I try.
My orignal thread isn't about there being duplicate ids. It's about there not being duplicate ids but an error saying there is and the reason for that being that the serialization and deserialization of state is broken. I think the error you were seeing is because myfaces generates id's for component in a place where the RI doesn't. ----- Original Message ----- From: "Jon Travis" <[EMAIL PROTECTED]> To: "MyFaces Discussion" <[email protected]> Sent: Thursday, April 28, 2005 7:13 PM Subject: Re: duplicate ids > Just wanted to point out something interesting > in my investigation: > > I've been pretty busy with other things, but decided > to try throwing the Sun reference implementation in > with custom MyFaces components. > > Well, I booted up my app -- things started to look > promising, then I hit a page and got an error with: > > "The following JSF tags are required to contain IDs:"h:outputText"" > > On further investigation, I found this on the web: > http://forum.java.sun.com/thread.jspa? > forumID=427&messageID=2126299&threadID=446525 > > I'm a long way from being able to convert all my JSF components > to having IDs, but it's a start. Rob, if you have a smaller > app, you might want to give this a try. > > -- Jon > > > > > On Apr 23, 2005, at 7:24 AM, Rob Decker wrote: > > > That's my point. The problems don't occur until you reach a size and > > level > > of complexity that you would probably find in alot of real world apps. > > A > > simple example isn't going to cause them. > > > > Test case 1: > > > > Just take a fairly complex html or jsp page, throw a panelGrid in it > > somewhere, add a bunch of verbatim tags where needed (now we are in a > > subview) and away you go. > > > > Replace the error message with "lost track in the component tree > > structure". > > > > Test case 2: > > > > Add a fairly complex tree2 structure, add a dataTable that uses the > > same > > backing data, render the tree, hide the tree and render the dataTable, > > hide > > the dataTable and render the tree. Click on a node in the tree to > > expand it. > > > > Replace the error message with "lost track in the component tree > > structure". > > > > The fix: > > > > The findComponent method is part of the deserialization process for the > > component tree. These errors could be occuring because the > > serialization was > > probably broken. > > > > I don't know enough about the specification (see the findComponent > > javadoc > > for some info) at this point to fully understand what's happening here > > but I > > think it is necessary for anyone who is going to fix these issue to > > understand the process fully (specification) and all the related code > > that > > implements it. > > > > Once that's accomplished you'll be going "ah hah!"...refactor/rewrite > > then... > > > > Simple examples aren't going to cut it alone. Fairly complex test > > cases are > > going to be needed to put the code through it's paces. The two above > > would > > be a start. In the end the code needs to be able to serialize and > > deserialize a component tree structure of any complexity without > > throwing > > fatal exceptions (ok maybe you want to throw for real duplicate id's > > but you > > could also ignore all but the first, or last, and let the user figure > > out > > where they went). > > > > These aren't actually all that complex examples. I'd think they'd be > > pretty > > common usage for myfaces/jsf applications. In fact, I'm sure there is a > > potential to become even more complex once myfaces gets past these > > issues. > > > > > > ----- Original Message ----- > > From: "Jon Travis" <[EMAIL PROTECTED]> > > To: "MyFaces Discussion" <[email protected]> > > Sent: Saturday, April 23, 2005 12:22 AM > > Subject: Re: duplicate ids > > > > > >> If you have a very simple example that shows this problem, > >> please post it so we can work on a solution. Unfortunately > >> my setup that breaks is fairly large. > >> > >> -- Jon > >> > >> > >> On Apr 22, 2005, at 4:15 PM, Rob Decker wrote: > >> > >>> I've seen that exception with the verbatim tag as well. It was one of > >>> the > >>> reasons I started stripping out jsp/html code. > >>> > >>> In my opinion, release software shouldn't be throwing out fatal > >>> exceptions > >>> like these two examples. > >>> > >>> Specifying ID's everywhere will not help all that much. If the > >>> component > >>> tree gets too big and complex, things start breaking. Code like this > >>> is not > >>> designed to handle it and the fact that it's throwing an exception > >>> with a > >>> misleading message to mask an earlier blunder is just an indication > >>> of > >>> what's underneath it. > >>> > >>> This code needs to be fixed if myfaces is going to move forward to > >>> handle > >>> real world application development. The application I'm writing is > >>> really > >>> simple from the UI perspective. I shouldn't be having this much > >>> trouble with > >>> it. Personally I think software marketeers should tag there 1.x > >>> releases as > >>> betas just to show a little honesty and integrity. > >>> > >>> > >>> > >>> ----- Original Message ----- > >>> From: "Jon Travis" <[EMAIL PROTECTED]> > >>> To: "MyFaces Discussion" <[email protected]> > >>> Sent: Friday, April 22, 2005 6:40 PM > >>> Subject: Re: duplicate ids > >>> > >>> > >>>> Seems as though there are more problems with that method > >>>> than just the one you're pointing out (may be related, though). > >>>> > >>>> I have a verbatim tag that actually blows up with a > >>>> ClassCastException > >>>> in the doEndTag when trying to cast to a UIOutput. > >>>> > >>>> Since the component type is defined to be javax.faces.Output, > >>>> you'd expect that this would always succeed. > >>>> > >>>> Unfortunately, in the UIComponentTag, findComponent() does: > >>>> > >>>> _componentInstance = parent.findComponent(id) > >>>> > >>>> which (in my case) happens to return a panel grid. > >>>> > >>>> Note, I'm not specifying any IDs in any of my tags. It appears > >>>> that if you want to be safely using myfaces, you'll have to be > >>>> specifying IDs everywhere. > >>>> > >>>> -- Jon > >>>> > >>>> > >>>> > >>>> > >>>> On Apr 22, 2005, at 8:32 AM, Rob Decker wrote: > >>>> > >>>>> I'm looking over the UIComponentTag.findComponent(id) method where > >>>>> this "problem with > >>>>> duplicate ids" exception is thrown. This code doesn't even check to > >>>>> see if the id is a > >>>>> duplicate. It simply checks if more children were added to the > >>>>> parent > >>>>> than the size of > >>>>> the list of children the parent has. The component in question > >>>>> isn't > >>>>> one of the > >>>>> children because just prior to (and the reason for) executing the > >>>>> code > >>>>> that throws > >>>>> this exception was that the id wasn't found as a child of the > >>>>> component. > >>>>> > >>>>> The issue here is that sometime earlier the code lost track of the > >>>>> count of siblings > >>>>> and this exception only masks that bug. The comments don't give a > >>>>> reason for adding > >>>>> this index check but there is a comment about it: > >>>>> > >>>>> * Revision 1.16 2004/04/20 10:54:21 royalts > >>>>> * added index check to findComponent > >>>>> > >>>>> > >>>>> Does anyone have any info on this? > >>>>> > >>>>> -- > >>>>> Rob > >>>>> > >>>>> @objectsource.org > >>>>> > >>>>> > >>>>> > >>>> > >>> > >>> > >>> > >> > > > > > > > >
