Raible Designs

Resin now Open Source?

I noticed on the release notes for Resin 3.0.9 (released last Saturday) that they now have an open source (GPL) version.

Resin Open Source (GPL) - Contains all functional components of Resin, including EJB, but excludes performance and clustering capabilities.

Excludes performance capabilities? What does that mean - is it slow on purpose?

I was planning on looking at AppFuse on Resin again tonight and hopefully figure out a way to make it easy to setup/test/deploy on Resin instead of Tomcat. Since AppFuse currently works fine on Resin, this shouldn't be too hard. The hard part is going to be finding a non-obtrusive way to setup Resin.

With Tomcat, I can copy a couple JARs to $CATALINA_HOME/common/lib and an appfuse.xml file to $CATALINA_HOME/conf/Catalina/localhost and the app is setup and ready to go. Better yet, I can use Tomcat's Ant tasks to deploy a WAR with an embedded context.xml file and it'll get copied to the appropriate location.

Is there a similar system that Resin allows? I know I can do the copy-JAR thing. However, the last time I checked, you had to manually edit the resin.conf file to import a <web-app> definition.

Laszlo Goes Open Source

It's awesome to see that Laszlo has gone open source. The main reason I haven't dug into Macromedia's Flex is because it's $12K per CPU. I agree that this it's probably worth it if you're after a nice user experience - but most of my clients want open source, and only open source. It's tough to find folks that'll pay for JIRA even - if you can believe that.

With Lazlo going open source, it opens a whole new world for me. Now there's an opportunity to use this technology with clients. Of course, now I have learn the stuff so I can be productive enough to convince them to use it. I may even add a Lazlo front-end to AppFuse, but probably not until next year, after Tapestry and JSF. Hmmm, if JSF is really all that - can it render a Laszlo UI? That'd be wicked.

Integrating WebWork into AppFuse

Last week was a busy one as I was trying to finish up AppFuse 1.6 before starting my new gig (more on that later). Most of this involved 1) integrating WebWork and 2) writing the Ant-based installer for replacing Struts with WebWork. I've worked with WebWork before, so this post is mostly an extension of that - as well as documentation on what I did so others can understand AppFuse+WebWork better. Below is a list of things I found.

• WebWork's concept of "results" are very similar to Struts "action-forwards". However, they also allow you to chain to other actions and use expressions.
• Implementing the ModelDriven interface in your Actions is a good idea, but it's not that great. I found that by simply using get/setUser(), I got the same functionality - except that I had to add "user." to all my form elements in my JSP. The advantage to doing things this way (over ModelDriven) is you can have an Action that services many objects. The main reason I'm not using ModelDriven is because the following tag doesn't render the label (it's just blank). Strangely enough, it renders just fine after validation fails.

    <ww:textfield label="getText('user.firstName')" name="'user.firstName'"
        value="user.firstName" required="true"/>

• WebWork is similar to Tapestry in that they encourage you to specify i18n messages (properties files) on a per-action basis (Tapestry is per page). Some might think this is a good idea, but after using Struts and Spring, I'm used to using one ResourceBundle for everything. To migrate AppFuse from using 1 bundle to many bundles just for WebWork would've been a pain. Luckily, in WebWork 2.1, they added the ability to specify a custom bundle using "webwork.custom.i18n.resources=ApplicationResources" in webwork.properties. I believe my issue with ModelDriven and labels is caused by this new feature.
• The Spring-integration provided by SpringObjectFactory is quite nice. Unfortunately, client-side visitor validation doesn't work with it.
• Unit-testing WebWork actions is easy, though it's kinda wierd to not send request parameters and such to set values (instead, you just set values directly on the Action).
• I experimented with putting stuff on the stack and pulling it off in JSPs, but never got it to work quite right. After failing the 10 minute test, I decided to just put stuff in the request and get it working. Looking through the code now, there's only 3 places where I'm stuffing attributes into the request: 2 in FileUploadAction and 1 in ExceptionHandlerInterceptor.
• With most frameworks I've used in the past, I rarely jumped into the source to try and see how things worked. Because of this, I rarely extended framework classes for my own use. However, with WebWork/XWork, I found it quite easy to dig in and extend the framework. Especially with Interceptors - which I dig.
• Following up on Interceptors, I was able to easily create my own ValidationInterceptor that cancels validation on GET requests, and when cancel or delete is clicked.
• Other interceptors that came in handy are a UserRoleAuthorizationInterceptor (which I borrowed from Spring) and an ExceptionHandlerInterceptor (which is modeled after Spring's SimpleMappingExceptionResolver). The 1st interceptor made it easy to mimic Struts' ability to declare a "roles" attribute on an action-mapping. The 2nd one allows you to map exceptions to results. This is something I was looking for when I first started using WebWork.
• The "required" attribute in WebWork's JSP tags have nothing to do with validation, except that they add an asterisk to the field label. I'd rather this be integrated with validation - where an asterisk shows up when a field is "required" in its Action/POJO-validation.xml file.
• I had a few other issues with validation: client-side validation shows one error at a time, client-side validation doesn't allow cancelling and field errors are displayed in a random order. If I were to start a project tomorrow that wanted WebWork with client-side validation, I'd probably try to integrate Commons Validator.
• Testing Actions is easy, as it should be. Using Spring's Servlet API mocks made it easy to test Actions that used ServletActionContext to set cookies and other such request-related stuff.
• I dig the rich set of form tags and it's great that these can be easily customized. I customized a few for AppFuse to make the syntax a bit more XHTML-compliant.
• I'm a stickler for formatting and good-looking XHTML in JSPs. I try to keep lines less than 80 characters. Here's a comparison of the LOC required by the different frameworks for userForm.jsp:
  • Struts: 298
  • Spring: 319
  • WebWork: 186

All in all, I enjoyed working with WebWork and if given a choice of an AppFuse combination to use on my next project - it would probably be WebWork+Hibernate. If the client wanted client-side validation, I'd either integrate Commons Validator (which shouldn't be too hard) or use Spring+Hibernate. After using Spring and WebWork, which allow you to use your model objects directly in the view, it would be tough to go back to Struts. However, I still do know Struts better than the other two - so if I had a really tight deadline, that might be the smart way to go.

[ANN] Cargo 0.2 Released

Download · Release Notes · Learn More · Project Weblog. I've been looking for something like Cargo for a while now - mainly so I could provide an easy way to test JSPs (and therefore the whole app) in-container. For the last couple of years, I've been using Cactus' <runservertests> task, but it requires you to configure your own startup and shutdown targets - which can be difficult for the different containers. Cargo makes this easy. So easy that I've added it as a topic to Chapter 8 of Spring Live. BTW, the MyUsers sample app shows you how to use jMock and Easy Mock for isolating Manager tests and Action/Controller tests - something that I might eventually move to with AppFuse.

In 1.5, AppFuse's build.xml is tightly coupled to Tomcat for running Cactus tests and Canoo WebTests. There are only a couple of Cactus tests in the Spring and WebWork versions - LoginServletTest and ActionFilterTest and I believe I can use Spring Mocks to refactor those and test them out-of-container.

Using Spring's ContextLoaderPlugin for Struts, I should be able start testing the Struts Actions using MockStrutsTestCase too. This means that the only in-container tests will be Canoo WebTests. As part of 1.6, hopefully you'll be able to run the "test-web" target sans container. Right now it sounds like quite a challenge, but being able to run Spring's Controllers and WebWorks Actions out-of-container is a really nice feature. Furthermore, removing Cactus as a dependency would open the doors for using JDK 5.0.

I'm also hoping to add support for switching containers - by running a simple script that nips and tucks the build.xml. For 1.6, I'll try to add an installer for Resin. If it's easy, I might take a stab at Jetty and Orion too.

Update: Cactus is gone - there's no need for it anymore as all actions/controllers, filters and listeners can be tested out-of-container. The best part is I didn't have to change any application code - just a few tests. Sweet!

The Beauty of SiteMesh

I'm pumped that I recently switched from Tiles to SiteMesh in AppFuse. Not only was it easy to learn when I integrated it into Equinox, but it easy to replace Tiles with SiteMesh in AppFuse.

The best part of SiteMesh is once you have it setup and configured, you rarely have to muck with it again - it just works. In fact, it's so non-obtrusive that when I re-worked all AppFuse's tutorials last week, I was able to delete a whole tutorial. That's right folks, by removing Tiles and going with SiteMesh - the number of tutorials dropped from 5 to 4. Reduction in code and words needed to explain it is always a good thing.

Furthermore, SiteMesh continues to be evolving and getting better. Good stuff.

BTW, did you know you can use SiteMesh-style templates in your Roller blog? I'm using this feature on JRoller and it works great.

AppFuse 1.6 almost done

I spent many hours and quite a few late nights this week working on AppFuse. It's funny how little sleep you can live on when you're working on something you're passionate about. There's only a few items left on the 1.6 roadmap, so I hope to do a release in the next week or so.

The major new feature in 1.6 is WebWork as a web framework choice. If you'd like to dig in and take AppFuse+WebWork for a test-drive, checkout AppFuse from CVS and execute "ant install-webwork". From there, the tutorials are a good place to start. The QuickStart Guide has more detailed instructions.

If you don't want to do the DAO and Manager stuff, and you'd rather just dig into WebWork, you can download the files from the first two tutorials and extract them into your project.

For a complete list of changes (so far) in 1.6, see the README.txt in CVS. You can also checkout the following demos:

• Struts, Spring and Hibernate
• Spring MVC, Spring and iBATIS
• WebWork, Spring and Hibernate

I'll try to write up a detailed post about my WebWork experience in the next couple of days. In the meantime, let's just say I dig it.

Playing with JDK 5.0 and Tomcat 5.5.2

I did some experimenting this evening with JDK 5.0 and Tomcat 5.5.2. The good news is that AppFuse compiles fine with JDK 5.0 and runs on Tomcat 5.5.2 nicely too. Here's a couple of things I found:

JDK 5.0
I received a number of interesting errors from the new JDK. Here's one of them:

   [javac] Note: Some input files use unchecked or unsafe operations.
   [javac] Note: Recompile with -Xlint:unchecked for details.

I received a few other messages that were deprecation warnings. The wierd thing is that it was telling me what's deprecated in HttpServletResponse, rather than what's deprecated in my code. Huh - what's the point?

Unfortunately, I found that Cactus won't run on JDK 5.0. Too bad, everything else seems to work fine.

Tomcat 5.5.2
I like the speediness of the new Tomcat, but I was disappointed to find out that they changed the DTD for the context.xml file. The old one works fine on Tomcat 4.1.x and 5.0.x, but you have to make some modifications for it to work on 5.5.x. To be fair, the new syntax is shorter and more concise. I've updated AppFuse's build.xml to detect Tomcat 5.5 and swap context files as appropriate.

Because of the Cactus bug, I think I'll be sticking with JDK 1.4.2 and Tomcat 5.0.28 for now - but it's cool to know that everything else will work once Cactus is fixed.

[ANN] Struts Menu 2.3 Released

Download · Release Notes. This release's major feature is the complete de-coupling from Struts - so that no struts.jar is required in the classpath anymore. Of course, if you have it in there, it's used as before. This release was primarily motivated by my need to include this in the WebWork version of AppFuse. In addition, I fixed a lot of bugs that I never even realized were entered. I'm monitoring the tracker's now - hopefully the delay won't happen again.

Additional Struts Menu Links:

• Project Home
• Demo

WebWork's Validation and SpringObjectFactory

For the last couple of nights, I've been wresting with WebWork's validation framework and trying to get it's client-side stuff to work with AppFuse. After much frustration, I finally figured it was caused by the SpringObjectFactory class. By using this patch, I was able to get regular client-side validation to work, but not the VisitorFieldValidator - which is what I'm using for almost all validations.

Since I've been done with the WebWork integration into AppFuse for a few days now, I think it's time to cut my losses and start working on other stuff for the 1.6 release. Hopefully someone will figure this out someday, but in the meantime, the server-side validation should satisfy most requirements.

In other words: there will be no client-side validation for WebWork in AppFuse 1.6.

Update: After playing a bit more tonight, I almost added client-side validation by specifying the validation rules per-action rather than per-POJO. Then I discovered that the client-side validation has no way to cancel its invocation. With Commons Validation, you can add an onclick handler to a submit button (onclick="bCancel=true") to cancel client-side validation.

Damn

It's 8:20 a.m. and I still haven't gone to bed yet. The good news is I got a lot done on Spring Live and AppFuse in the last 10 hours. I guess I just lost track of time...