In Seam, in the pages.xml or mypage.page.xml files, you note that a given page requires the user to be logged in to view the page. It is a very easy way of handling simple security. What happens is if a user attempts to access a page with the login-required="true" attribute and they are not logged in, they are automatically redirected to your login page (as defined in your pages.xml). Once they login, they are automatically redirected back to the page they had attempted to access initially. Very elegant, and much easier than writing all that yourself.

There is however a "gotcha" you should be aware of in this flow. If you use the login page, or logic, to start a long running conversation (I do this because my User entity object has some large binary properties which I want lazily loaded), the post-login redirection will kill that conversation. In my case this led to lazy loading exceptions down the road.

It took me a while to figure out the cause, as it only happened much later in the application, and most of the time it worked (when I logged in purposefully from the main page), but sometimes would break (when I'd had an expired session and gone through the login auto-redirection flow). Eventually though I was able to track it down to those two scenarios.

What is happening is this: before the first redirection happens (to the login page), the Seam Redirect classes captureCurrentView method is called. This basically saves the information about the page you were trying to view (it's a little more complex than that- being all Faces like and whatnot, but that's the gist of it). This method creates a long running conversation in order to hold this state across the multiple pages. If there was no previous long running conversation to join, and it had to create a new conversation, it stores a conversationBegun flag of true.

Then you hit the login page, where the page (or code) would Begin a long running conversation, except you almost certainly have join=true, so it joins the existing long running conversation, which was created by the captureCurrentView method. This is the conversation your User entity was loaded up in.

After your login was successful, the Redirect classes returnToCapturedView method is called to send you back to where you'd tried to go initially.

This method has the following block:

 
if (conversationBegun) {
       Conversation.instance().end();
}
 

This ends the conversation you had loaded your User entity within, and when you hit your destination page, there is no long running conversation at all. Then, a few minutes later, it's lazy loading exception time.

The downside is there isn't a really clean fix that I am aware of yet.

The upside is there is a pretty simple hack: just add a <begin-conversation join="true" /> to all of your pages which have the login-required="true" attribute. This creates a new long running conversation before the Redirect does it's work, so it in turn joins that conversation instead of creating a new one, the conversationBegun flag is false, and the returnToCapturedView method doesn't end your conversation. It's a hack, and you have to remember to add it to every page which requires a logged in state, but it does work.

Let's say that when a user clicks on something, perhaps selecting something from a DataTable or DataGrid, you want to call some server side code, and then popup a modal panel which needs to show content based on the new state setup by your server side call. In my case I have a DataGrid showing a number of items, and when a user clicks on an item I want to set the current selected item on a Seam component on the server, and then popup a modal panel to display detailed information about the item, and provide the user some actions within the modal panel.

Looking at the solution it seems so simple, but for some reason it took me hours of trying different combinations, orders, tags, JavaScripts, etc... before I could get this to work correctly. I had the panel appearing with the old data, or appearing with the old data and then disappearing completely, only to show the so called new data the next time I clicked on an item, or rendering on the page itself below the footer, or not popping up at all, or popping up with null data, or.... So I'm posting it up here for myself and anyone else who runs into issues.

First, create your modal panel (rich:modalPanel). I do this in a separate .xhtml file, as I will use the same model panel in various pages throughout the site. In your modal-panel.xhtml file (or whatever you choose to name it), start with a <ui:composition> tag, define your RichFaces xml namespace (and any other JSF libs you'll be using), and then setup your <rich:modalPanel>. You need to give the modalPanel a unique id, in this case we'll call it "myModalPanel".

<rich:modalPanel id="myModalPanel" autosized="true" zindex="2000">

Inside your modalPanel tag, you need to define an inner div. This is the div which you will be rerendering after the server action is complete. I use tags, as I'm using Seam. Ensure that any references to backing beans or data that you want refreshed are within these div tags. You must give this div a unique id as well, in this case we'll call it "myModalDiv".

<s:div id="myModalDiv">

The one limitation that I've run into here, and if you know how to solve this, please let me know, is that the <f:facet> tags for your header text and controls can't be inside this div, and you can't put the div around the whole modalPanel (or it makes the panel disappear when you rerender). As such you can't make anything from the <f:facet>s be updated on rerender. This is preventing me from having the modal panel header displaying the current selected item's name. Not great, but not the end of the world.

So inside this div you have your dynamic output. I have lots of

<h:outputText value="#{backingBean.selectedItem.property}" />

type entries in mine.

On your actual page where you will be displaying the modal panel from you need to include the modal-panel.xhtml file, I use a:

<a:include viewId="/modal-panel.xhtml" />

Then, I have my page, which includes a rich:dataGrid, and inside it has an <a:commandLink> which creates the AJAX clickable item. This commandLink has to call the backend action, display the modal panel, and rerender your div.

 
<a:commandLink id="showItem" action="#{backingBean.setSelectedItem(item)}"
oncomplete="Richfaces.showModalPanel('myModalPanel',{width:550, top:200});"
reRender="myModalDiv">
    Click Here!
</a:commandLink>
 

This makes the panel display, and then the new content is rendered in the panel. It seems to work just how I wanted it to. With the minor annoyance of having to use a static modalPanel header.

RichFaces, a collection of open source JSF Components for building "rich" AJAXy interfaces, unfortunately makes Safari crash or hang or lock up with many of it's components.

I'm not the one who figured this out, but I wanted to document it here.

You can solve this the same way you solve the JSF/Google Ad issue:

Add this just before the tag on your .xhtml pages or template file:

<f:view contentType="text/html" />
 

I upgraded the JBoss instance on my server just over a week ago from 4.0.5 to 4.2.0. Two things happened after that: Firstly, my google adsense revenue dropped by half, secondly I was contacted by two different people who were having some e-mails show a big error in Firefox, instead of showing up correctly. I don't use Firefox myself, I use Safari about 98% of the time and Camino when I find a site that doesn't render correctly in Safari. Today I discovered, while working on a new ad layout, that in Firefox the Google ads weren't rendering at all, throwing this error in the Firefox error console:

Error: uncaught exception: [Exception... "Object cannot be created in this context" code: "9" nsresult: "0x80530009 (NS_ERROR_DOM_NOT_SUPPORTED_ERR)" location: "http://pagead2.googlesyndication.com/pagead/show_ads.js Line: 4"]

Basically iframes can't be programatically inserted into strict xhtml elements. I did some googling and discovered that there were some discussions around this, but most of them simply said "either ditch google ads, or use text/html instead." But I WAS using text/html, both in the meta content tag in the pages, and then later (while working on this issue) in the JBossWeb web.xml mime type configuration for xhtml, just in case. Using wget with --save-headers didn't show anything unexpected. However, Firefox kept getting the response header saying the page was application/xhtml+xml which caused it to perform very strict validation, both breaking the google ads, and not letting sloppy tags or duplicated tags into the page, which are inherently going to happen when you're rendering html e-mail within a page.

The cause of the break was not moving to JBossWeb in 4.2.0, nor any JBoss code itself. It turns out that when the JSF implementation was changed from MyFaces to Sun's JSF-RI as part of the JBoss and Seam upgrade I did, the default content mime type changed as well. JSF-RI sets it to application/xhtml+xml. The fix was simple, add the following tag just before the <head> tag in each .xhtml faclets page:

<f:view contentType="text/html"/>