Raible Designs

Mapping buttons to methods

In AppFuse, I use Struts' LookupDispatchAction to map submit buttons to methods in my Actions. It's caused quite a headache for i18n, but Jaap provided a workaround and now everything works fine. However, as I did the Spring MVC implementation this weekend, I didn't have to do any complicated "button value -> method name" mapping. Part of it was because I didn't need to, but also because I discovered that you can easily just check if the button's name was passed in. Explaining this with code is probably easier. Let's say you have three buttons on a page:

The HTML code for the above buttons is:

<input type="submit" name="save" value="Save" />
<input type="submit" name="delete" value="Delete" />
<input type="submit" name="cancel" value="Cancel" />

Using the name as your key, you can easily check in your Action/Controller/etc. to see which button was clicked:

if (request.getParameter("save") != null) { 
    // do something
}

The nice thing about this is that it doesn't care what value you put on your button - just what you name it. It seems like all frameworks should use something like this, rather than a single parameter name (i.e. "method") that requires JavaScript on a button to change the method invoked. About a month ago, Rick Hightower mentioned that he uses a ButtonNameDispatcher for Struts. Rick, if you're reading this - I'm ready for that bad boy!

Converting AppFuse to use Spring for MVC

It's been a long and painful week - with 3 or 4 nights where I was up to 4 or 5 in the morning. Last night I was up until 4:30 and Abbie woke me up promptly at 7:30. Ugh, sleeping more is probably a good idea. I started on the Spring MVC layer for AppFuse on Thursday night and it took me almost 2 days to convert everything. There's still a few kinks and workarounds - but if you're running it through a browser, everything works the same as it did with the Struts version. The hardest part about it was writing the unit tests. With Struts, it's rather easy b/c I use StrutsTestCase, which provides a very simple API for testing Actions. I'm sure Spring will soon have this same capability with its Servlet API Mocks, but I was definitely banging my head against the wall a few times. I did manage to convert the LabelTag to recognize required fields and error messages. The JSP conversion was a slight pain - but mostly because you have to type a lot more for input fields than you do for Struts. I'm looking forward to WebWork which requires one line to do the whole table row. It has Velocity templates for its tags and they write the <tr>, <label> and the <input>. Pretty slick IMO - less typing is always attractive to me.

I'd like to write-up a detailed entry on "migrating from Struts to Spring" on JRoller, but it's been flakey over there for a few days now - so I might just do it here. We'll see - the lack of sleep is draining my motivation to write. I hope to do the Ant-based installation for Spring in the next couple of days - then I'll release 1.5 beta. My main reason for the beta is because the Spring stuff can probably be cleaned up a lot, as well as it gives me time to write documentation before the final release.

Why Hibernate Rocks - easy database switching

The app I've been developing over the last 6 months is going live next week. As part of that process, my client decided they wanted to put the production database on their AS400, rather than their JDE/WebSphere/DB2 Server. Hibernate and AppFuse made this super-easy. Add the JDBC Driver, specify a new dialect/jdbc url/driver name, and voila - we're talking to DB2400! After creating the initial tables using Ant we noticed that the table names were too long since the 400 has a limit of 10 characters. To fix this, I simply modified my XDoclet @hibernate.class table="..." to have shorter table names. After that, I simply had to re-arrange a few tables in my sample-data.xml file (for DBUnit) to avoid referential integrity issues. All-in-all, we migrated from MySQL to DB2 on an AS400 in a little under an hour this morning. Hibernate makes my development life soooo much easier.

What should we do with Tiles?

There's some discussions taking place on the Struts Developer Mailing List about what to do with Tiles. Tiles is gaining popularity in frameworks other than Struts - i.e. Spring and JSF. Personally, I don't mind that Tiles is buried deep inside struts.jar b/c it's basically the difference between a 500 KB JAR and a 100 KB JAR - and disc space is cheap! However, an advantage of extracting Tiles from Struts is that it then has the opportunity to become friendlier to other web frameworks. I'd even like to see a Sitemesh-like Filter so you could do Sitemesh stuff with Tiles. Or maybe just bundle Sitemesh with Tiles as a kick-ass templating engine.

So the question is: What should we do with it? Should it become a Jakarta Commons project or a Jakarta Project? Or even a java.net project? Tiles Users - we need your feedback!

Goals for the week with XDoclet, Spring and AppFuse

I have a lot that I want to accomplish this week. Hopefully a few late nights will make it possible. I'm posting this list here in case someone has already done some of this.

• XDoclet: duplicate the Struts-specific <validationxml> Ant task for Spring. Make it work with POJOs. This is primarily motivated by the fact that I got the commons validator stuff to work just like it does with Struts.
• XDoclet: create a new <strutsform> task that doesn't depend on ejbdoclet. This will allow me to remove AppFuse's dependency on j2ee.jar.
• Spring: extract the mock objects used in Spring's internal test suite so I can use them to test Spring Controllers (springtestcase? ;-)).
• AppFuse: finish Spring MVC integration and release 1.5 beta.

Phew - it's gonna be a rough week with very little sleep. Fortunately, it'll all be worth it if I can pull it off.

Update: Sometimes things just click: generate validation.xml for Spring and generate ActionForms from POJOs w/o an EJB dependency. I also discovered that <hibernatedoclet> requires that xdoclet.modules.ejb.EjbDocletTask is in the classpath. It doesn't make sense, but the compiler doesn't lie.

Logout your users automatically after their session times out

One of the common issues I see in webapps is a user leaves their computer, their session times out, and when they come back to do something - the app throws errors b/c their session is null. There are several easy ways to fix this. If you use Container Managed Authentication, the user will likely be prompted to do login and can continue as before. If you're using a slick Remember Me feature (like AppFuse has), the user won't even notice. However, you might not have these options available to you. For those circumstances, I recommend you put a meta-refresh in your app to automatically show the uses a timeout message when their session expires. It's as simple as the following:

<meta http-equiv="Refresh" 
  content="${pageContext.session.maxInactiveInterval}; url=timeout.jsp"/>

I used JSP 2.0's EL in this example for simplification. If you're using a JSP 1.2 container - you'll have to wrap that expression with a <c:out> tag.

CSS Drop Shadows

A List Apart has a new article on how to make CSS Drop Shadows that work in IE. The first article shows how to do it for all the other browsers. I dig the technique, so I've decided to use it on this site. To add it, all I did was add the following to the <head> of this page:

<style type="text/css">
    div.alpha-shadow {
        clear: both;
        float: left;
        background: url(http://www.alistapart.com/d/cssdrop2/img/shadow.gif) no-repeat bottom right;
        margin: 5px 0 0 10px;
    }
    div.alpha-shadow div {
        background: url(http://www.alistapart.com/d/cssdrop2/img/shadow2.png) no-repeat left top !important;
        background: url(http://www.alistapart.com/d/cssdrop2/img/shadow2.gif) no-repeat left top;
        float: left;
        padding: 0px 6px 6px 0px;
    }
    div.alpha-shadow img {
        background-color: #fff;
        border: 1px solid #a9a9a9;
        padding: 4px;
        margin: 0;
    }
</style>
<!--[if gte ie 5.5000]>
<link rel="stylesheet" type="text/css" href="http://www.alistapart.com/articles/cssdrop2/ie.css" />
<![endif]-->

Then I wrapped the following image with:

<div class="alpha-shadow">
  <div><img src="..." alt=""/></div>
</div>

If I decide I like this, I'll make sure and download the images/stylesheets locally so not to hog bandwidth from alistapart.com. Too bad there's not a technique to make text drop-shadows work. To see what I mean, see my Struts Resume demo. All the <h1> tags (titles) should have a drop-shadow - and they do in Mozilla, Firefox and Safari (but no go in IE).

The real question is - how do I get it to NOT float:left, but still get the drop-shadows to work? I guess I'll have to ask that question on alistapart.com.

Hmmmmm, my version doesn't work in Safari, what's up with that?!

Happy Anniversary Julie!

Today is Julie and I's 4-year anniversary. It's hard to believe that 4 years has gone by so fast. That's part of the reason I started this weblog - so I'd be able to document my life and know exactly what I was thinking on a certain date. Unfortunately, if I look back, I'll probably just see that (most of the time), a new Hibernate release came out. ;-)

I couldn't ask for a better wife or mother of my children. She really is the one for me and I couldn't be a luckier guy. Just for kicks, here's a picture on our wedding day. The funny thing is the picture is from exactly 4 years, 15 minutes ago. We got married at 5 p.m. EDT, and I suspect this picture was taken around 5:45. We'll be celebrating tonight with a babysitter and a nice dinner out.

Full Time vs. Contract

I talked with some folks yesterday about joining their company as a full-time employee. Their opportunity sounds awesome: using open source tools to develop a product. The opportunity certainly appeals to me. In a sense - I could get paid to work on AppFuse. I could get paid to do the stuff I wake up early and go to bed late for. I could spend more time with my family because I'm doing my "moonlighting" stuff during the daytime.

At least that was their sales pitch.

In reality, no company in their right mind is going to pay me to work on all the open source projects I contribute to: AppFuse, Roller, Struts Resume, Struts Menu and DisplayTag. Sure, they might allow me to work on AppFuse and Roller for a few hours a week, but I can guarantee that I'll still want to contribute to the others - and hence, continue to burn the midnight oil. I've also started to think that the main reason for doing stuff "after hours" is because I spend my evenings with Julie and Abbie - whereas I used to work in the evening.

More than anything, the opportunity really got me thinking about doing full-time work vs. contract work. I've been doing contract work for almost 3 years now - and I've only had 2 months of no work in that 3 year period. So that whole contracting is so unstable has been a myth for me. In fact, I see contracting as more stable than an employee position because I control my own destiny for the most part. NOTE: This post is likely a bit biased because my contract just got extended until the end of the year and I'm working on an AppFuse-based application. In other words, I love my job right now.

The thing I enjoy the most about contracting over full-time is freedom. I am planning to take 7 weeks off in the next few months (3 weeks for Spring Live, 4 weeks for the new baby) - and with a full-time gig, that would be impossible. I also like the ability (again, this is probably because my current client is so cool) to take a week off to attend a conference, or take a few days off to run off and do some training. The fact that I'm not tied down to one client/company is awesome. With the full-time opportunity I'm considering, I feel like I'd be marrying a woman I met just a few weeks ago. I guess most full-time gigs are like this after you've been set free with contracting.

One of the main reasons I'm considering this full-time gig is because I don't know where I want to be in 5 years. Most of my career aspirations have been met. When I started in this industry, I wanted to gain enough knowledge about what I do to speak at conferences and such. I did that last week and it was a blast - but I don't really want to do that every month - especially if I have to travel. Traveling away from my family is no fun - and happiness is more important than anything. The nice thing about the full-time gig is that its centered around a product, rather than services. Services (i.e. consulting) are great - but they're only good as long as I'm capable of working. Developing products that earn money while you're on vacation - that's the ideal situation.

The only thing I don't like about my current contract is that I'm a lone wolf. I'm the only guy developing the current app - which is great, but there's no "team spirit." My favorite job ever had awesome team spirit. This opportunity is a startup, which often leads to team spirit - but they also enticed me with ideas of working with a smart bunch of developers. If you've ever worked with smart people, you know that this is a real treat. Learning from your peers just by going into the office is quite a rush. When someone tries to find their answer on Google before asking you - it's refreshing. But is this worth giving up freedom for?

Another important consideration is compensation. Contracting tends to pay 50%-100% more than a full-time position. Of course, this full-time opportunity has options (which supposedly narrows the gap), but we all know that those rarely come to fruition. And if they do - it usually takes a couple of years. I am well aware that a cool job is waaayyy better than a good paying one, but still - getting paid well is nice.

Lastly, to throw a wrench into everything, someone sent me an e-mail last night suggesting they might (someday) be interested in paying me to do full-time AppFuse development. Heh - now that sounds like the ultimate dream job.

How does your MVC framework handle duplicate posts?

One of the problems that you'll often see in webapps is that when a record is added - hitting refresh on the browser will cause a 2nd record to be added. This is because the "Save" action usually does a forward, rather than a redirect, and the full post is re-created. I'm curious to know how other MVC Frameworks handle this issue, particularly Spring, WebWork, Tapestry and JSF. In Struts, it's pretty simple to solve. When the form is first displayed, you'll likely go through an Action. In AppFuse, this would be something like UserAction.edit(). In the edit method, you add a saveToken() call to put a token into the session:

Then in the save() method, you can check for a duplicate post using the isTokenValid() method:

How does your Java MVC framework handle this? Do you have to programmatically handle it like Struts - or is it built-in to the framework to handle it auto-magically?