Raible Designs

AppFuse 2.0: JDK 5, Annotations and JSP 2.0

For the most part, I haven't used JDK 5 on any of my recent projects. You can compile and run AppFuse with JDK 5, but it doesn't use any JDK 5 features. After doing a code review at Bouvet last week and seeing how much cleaner their code is with Generics, Varargs and the Enhanced for Loop, I think it's time to dig in. I don't know how soon we'll start, but I think it's time to start creating a branch for AppFuse 2.0 - which will use these features. For AppFuse 2.0, I'd like to go whole hog, bleeding-edge and use all the stuff that's out there to make developer's lives easier. This includes JSP 2.0, Annotations (especially for Hibernate and Spring, as well as Tapestry) and all the JDK 5 features that seem useful.

Since most developers won't be able to deploy on a JDK 5-compliant server for quite some time, we'll continue to maintain the 1.x branch as JDK 1.4-compliant. I expect to release AppFuse 1.8.1 later this week (with mostly bug fixes + latest releases of Hibernate/Spring) and 1.9 in the next month or so. From there, we'll likely do 1.9.x releases with bug fixes and do all the major upgrades (i.e. Tapestry 4.0.x) in the new branch. Working with new features in JDK 5 should be a lot of fun.

I'm hopeful that we can get rid of XDoclet and we may even give Maven 2 a run for its money. Last week in Norway, I found that most Java developers were using Maven on their projects and I also discovered that many of the core Maven 2 developers are getting paid to work on it full time. There were even claims that Maven 2 is going to be twice as fast as Ant - which definitely intrigues me.

Later: I just realized the hardest part of this migration is going to be replacing AppGen. It currenly uses XDoclet templates for all the class templates - and we'll need a new solution based on annotations. Oh well, it's kind of ugly anyway, but it'll likely be difficult to figure out a new solution. Hopefully we can create some sort of tool that involves easy-to-customize templates and a GUI to drive it all.

Norway Rocks!

Norway has to be one of the coolest places on Earth. I've been here for a week now, and I'm definitely impressed. I didn't know what to expect when I left the U.S. - mostly because my last trip to a non-English speaking country was to Russia in the mid-90s. When I went to Russia, I thought it'd be a lot like the U.S. What I found was a beautiful country that was struggling to survive. I wasn't expecting a whole lot from Norway.

I'd heard it was modern, but I wasn't going to get my hopes up. When my laptop died on the way over, I thought I was in for it. I figured they probably didn't sell PowerBook cords over here, so I was screwed. Luckily, I was wrong. Unfortunately, I had to buy a whole new laptop - but it has been quite nice using a faster machine (1.67 MHz / 1.5 GB RAM) this week, with Tiger and all that jazz.

This week has definitely been tiring. I've given a fair amount of presentations in my life, and even done a few week-long training course. However, I've never talked as much as I did this week. I did a total of 7 sessions on Spring this week, at 3 different companies and 2 different JUGs. It was a lot of work, but it was also fun to meet so many enthusiastic Java Developers. Preaching the Spring gospel is pretty easy since it's such a kick-ass framework.

So what about Norway? It's very modern. In many ways, it's more modern than the U.S. It seems cleaner, the people are nicer, and apparently there's little crime and/or poverty. This is readily apparent from the moment you get off the plane. There's a "bullet train" from the modern/cool-looking airport into downtown Oslo. It takes about 20 minutes, and then you're wisked away into a historic city by the sea. I dig the train.

I've been staying at the Hotel Stefan in downtown Norway Oslo, which is about 5 blocks from the main courthouse and lots of historic buildings. I'm a block away from a castle too! The funny thing is all the westernization - there's a TGI Fridays down the street and Star Wars is playing at the local theater. Taxis are very cool - most of which are new Mercedes. The only downside I've seen so far is the beer is pretty expensive ($10/each).

I've taken a few pictures and hope to take several more while sipping on seome cold ones with the locals tonight. I'll try to upload the whole batch later this evening or tomorrow morning. My flight leaves at 11 a.m. and I'll be back in the Denver tomorrow night. The 16-hour flight home is going to be rough - good thing it's in first class. ;-)

AppFuse Videos

I know I said I'd never do an AppFuse video, but after having many requests - I decided to go ahead and make a couple. The first one is a demo of creating a new project and then installing and browsing that project in your browser - to see all the out-of-the-box features.

• http://demo.appfuse.org/setup.html

The 2nd one basically all the stuff that's done in the tutorials - using Spring MVC for the web framework. I create a Person.java object and then use AppGen to generate all the code for it. In this one, I make a number of mistakes (but solve them all). I thought about going fully happy-path, but then decided it was important to show some gotchas that might occur.

• http://demo.appfuse.org/appgen.html

I used the trial version of Camtasia Studio to create these videos. Thanks to Keith at KGB Internet for hosting the demo site for AppFuse. If you need Tomcat hosting, Keith offers an excellent service at a very good price.

Update: You can also download these videos for off-line use.

Update 2: I updated these videos for AppFuse 1.9.3.

[ANN] AppFuse 1.8 Released!

This release of AppFuse replaces Container Managed Authentication (CMA) with Acegi Security. Other major features include numerous bug fixes to AppGen and a refactoring of build.xml to use Ant 1.6 features. Eclipse and IDEA project files were also improved so you can easily run tests from within your IDE. A MyJavaPack all-in-one installer was also added so you can download everything you need for AppFuse at once. Eclipse and its plugins were not included in the initial release, but may be in a future release.

• Download
• Release Notes
• Learn more about AppFuse

If you find any issues, let us know.

Update: You can now see Demos and Videos.

Using DWR with Spring and Hibernate

For the past few weeks, I've been developing an application using Struts, Spring, Hibernate and the DWR project for my XmlHttpRequest framework. As you might remember, I used JSON-RPC for Ajax stuff on my last project. I found DWR to be much more full-featured and easier to use. This post is meant to capture some issues I encountered so others won't have to jump the hurdles that I did. For those of you that get bored quickly, here's a movie (QuickTime) of the app's Ajax features.

I've been using version 0.4 of DWR, and I haven't had a chance to try out version 0.5. When I first started using it, I ran into a ThreadDeath problem that was easily resolved by changing a log.debug message to System.out.println. I tried to reproduce this issue yesterday and couldn't, so who knows what that was all about. As far as configuring DWR in your webapp, that's pretty easy to do, and well documented. See the project's documentation or this Spring MVC HowTo.

Here are a few things I remember from my development experience.

• The examples are great, especially how to dynamically edit a table.
• When developing, make sure to set the "debug" init-param to "true". This allows you to go to http://location:8080/yourapp/dwr and see a screen that allows you to call methods on your exposed classes.
• In WEB-INF/dwr.xml, you need to specify a converter for each POJO you want to expose to your UI via JavaScript. I started out by converting a whole package, but found this to be *extremely* slow (we have a package of around 50 DTOs). So I changed it to be only the DTOs I was using. This turned out to take about 30 seconds to do the conversion, and was again unacceptable. The problem turned out to be that the converter was invoking all the lazy-loaded children for each DTO. My final solution was to create a NameValue object and only convert that. Then in my Spring bean, I populate it from DAOs and DTOs. I'm using Spring's OSIVF for Hibernate to ensure that DWR doesn't invoke lazy-loading.
• I had to override a few of DWR's JavaScript functions in util.js b/c they didn't work for me. I changed showById() and toggleDisplay() to use style.display='' instead of style.display='block' b/c this is what I've always used and block doesn't work that well. I also changed useLoadingMessage() to have a cleaner-looking load message.
• I used the Fade Anything Technique in this project and found that IE likes to have full 6-digit hex values for colors in CSS rules. The shorter 3-digit hex values simply don't work in IE.
• Using "test" buttons that only showed up for my username proved to be a great way to test the UI and the Ajax stuff. These buttons called a number of JavaScript functions to drive the UI and wait between invoking different functions using window.setTimeout.

All in all, using DWR was a great experience and I definitely plan to use it more in my projects. The client loves the app - especially since it's wicked fast and seems to work like a desktop app.

BabyBash - kids love it!

A few months ago, I saw Toby Reyelts' post about a game he wrote called BabyBash. I downloaded it when I first saw it and let Abbie play it. She loved it immediately, and would ask me to play it whenever she saw I was "working" on the computer. Of course, she'd say "Daddy - no working" first, and then say "play Abbie's game?".

Then I lost the link for a couple of months and this conversation turned very sour. A couple of weeks ago, I found the link and vowed to never let it go again. This morning, I gave Jack a run at the game (he's almost 8 months now) and he loved it too! It probably doesn't hurt that they're playing it on a 23" display.

If you've have small children, you should really let them try this game. Thanks Toby - you rock!

Why Wicket looks cool

I like the looks of Wicket for a couple of reasons - without even using the framework yet.

• Its project homepage looks good. If you're using a Java web framework, chances are you're developing UIs too. If you don't know how to make sites look good - it's time to find a new line of work IMO. Of course, learning how to make good-looking UIs is another option.
• Its Wicket Stuff project. It provides Hibernate, fValidate and Spring integration. It also appears to provide an option to use Velocity for your templates. I'm not sure what the Velocity integration provides - since HTML templates (ala Tapestry) should do everything that's needed.

What I don't like about the project:

• The Buzz page has a quote that's (apparently) from this site. Unfortunately, it looks like I said it - which I didn't.
• There's no books being written about it. If it's really that good - where's the books? Ruby on Rails will have 3 by the end of this year. Any good framework should inspire books to be written about it.
• The Wicket Stuff project has no documentation. Javadocs don't cut it. Tutorials are king.

I hope this project succeeds - Tapestry needs some competition and I don't think JSF is providing it. If JSF adds HTML Templates (or I figure out how to use Java Studio Creator to manage an AppFuse+JSF project), that's a different story.

Closures with CollectionUtils

Here's a pretty nifty trick for using closure's with Jakarta Commons CollectionUtils:

I wonder if there's any performance hit from doing things this way vs. a good ol' Iterator? Hat tip to Anand Subramanian.

Use SiteMesh to decorate multiple webapps

Did you know it's possible to decorate multiple webapps with the same SiteMesh decorator? I learned how to do this from the SiteMesh mailing list:

• Put sitemesh.jar in your container's classpath. You could put it into each webapp's WEB-INF/lib, but it looks like there's problems with that.
• Create and deploy a webapp that contains the common decorator.
• In each webapp's decorators.xml, add a "webapp" attribute to point to the webapp you deployed in Step 2.

  <decorators>
      <!-- load decorator from a different web-app deployed in the server -->
      <decorator name="main" webapp="some-other-webapp" 
          page="/decorators/main.jsp">
          <pattern>/*</pattern>
      </decorator>
  </decorators>
  

Try to do *that* with Tiles.

Upgrading to Spring 1.2 RC1 and Hibernate 3.0

I spent an hour or so on Friday upgrading Equinox and AppFuse to use Spring 1.2 RC1 and Hibernate 3.0. The upgrade for AppFuse was relatively painless, but the upgrade for Equinox failed. Equinox uses HSQLDB version 1.7.1. The main reason I use the 1.7.1 version is to avoid the infamous "lock exception" that the new HSQL version throws in standalone mode. With version 1.7.1, it seems you could have more than one connection open to the file-based database w/ no problem. I really like this feature in 1.7.1 b/c it means you can run the app in Tomcat and browse the database at the same time.

So what's the problem? Why can't I just use Hibernate 3.0 with HSQL 1.7.1? The problem is I like using the following setting as part of my "sessionFactory" bean:

<prop key="hibernate.hbm2ddl.auto">update</prop>

This setting will update the schema when you change mapping files, but otherwise leave the data intact. Furthermore, it'll actually create the tables if they don't exist. Not so with Hibernate 3. With Hibernate 3, using "update" doesn't create the tables. Of course, upgrading to a newer version of HSQL fixes the problem, but then I get the lock problem. My eventual solution will probably be to hack Hibernate or HSQL, but for now I just won't upgrade Equinox. Another solution might be to look at some other embedded databases. Of course, I could also require users to install a database to run Equinox - but I like having the "no setup required" feature.

Regardless of the problems I experienced with HSQL and Hibernate 3, upgrading AppFuse was pretty painless. Here's the set of instructions I sent to the mailing list:

1. Download Hibernate 3.0 and Spring 1.2 RC1.
2. Create a lib/spring-1.2-rc1 and put the following files in it (NOTE: spring.jar now contains aopalliance.jar):

       acegi-security-0.8.1.jar
       commons-codec.jar
       ehcache-1.1.jar
       license.txt
       spring-mock.jar
       spring.jar

3. Create a lib/hibernate-3.0 and put the following files in it:

       hibernate3.jar
       lgpl.jar
       lib/antlr-2.7.5H3.jar
           antlr.license.txt
           asm.jar
           c3p0-0.8.5.jar
           c3p0.license.txt
           cglib-2.1.jar
           dom4j-1.5.2.jar
           jta.jar
           jta.licence.txt
           oscache-2.1.jar
           swarmcache-1.0rc2.jar

4. Change the versions for Hibernate and Spring in lib/lib.properties. Also, change the hibernate.jar property to reference hibernate3.jar instead of hibernate2.jar.
5. In build.xml, change the "package-web" target to include all the Hibernate JARs instead of just specific ones:

   <lib dir="${hibernate.dir}/lib" includes="*.jar" excludes="jta.jar"/>

6. Change web/common/taglibs.jsp to use uri="/oscache" for the oscache taglib.
7. Search for "net.sf.hibernate" and replace it with "org.hibernate".
8. Search for "orm.hibernate" and replace it with "orm.hibernate3" (for Spring).

The major difference for Hibernate is you no longer need odmg-3.0.jar, but you do need asm.jar and antlr-2.7.5H3.jar. Let me know if you find any issues with these instructions. You could also just download AppFuse from CVS.

NOTE: The CVS version of AppFuse has an XDoclet version that only supports generating Hibernate 2.x mapping files. I believe there is support for Hibernate 3 in XDoclet's CVS - but I haven't had a chance to upgrade yet.

Update: Here's more on the HSQL bug that's not really a bug (according to a comment on the post). Regardless of whether it's a bug or not, it'd be nice to have the 1.7.1 behavior as an option - it's a great feature for get-started-quick apps like Equinox.