Raible Designs

Ajax on Struts with Patrick Lightbody

I'm sitting in Patrick Lightbody's presentation on Leveraging AJAX in modern web frameworks. The point of this presentation is to give a preview of what's coming in Struts Action 2.0. There are a number of other good sessions I'd like to go to, particularly Intro to Dojo, but I figured it's better to attend this talk since AppFuse will be moving to SAF as part of 2.0. We're in a fairly small room, and there's about 20-30 people in attendance. With 400+ people at this conference, the other sessions are likely packed.

Ajax is more of a technique, rather than a technology. Commons Ajax techniques include:

• Tabbed pane
• Validation
• Polling
• Tree widget
• Voting

For SAF, there are three core building blocks/tags: <saf:div/>, <saf:a/> (results evaluated as JavaScript) and <saf:submit/>. Divs are where things "happen" and links/submit buttons can trigger events. There are two frameworks used is SAF:

• DWR: Remote invocation service for Java <-> JavaScript
• Dojo: Language/server-agnostic JavaScript framework

There are two styles of Ajax: DOM manipulation (DWR) and partial pages (Dojo). SAF provides three Dojo widgets: BindDiv, BindAnchor and BindButton. The div tag supports the following attributes: href, updateFreq, delay, loadingText, errorText, showErrorTransportText, listenTopics and afterLoading. A simple example is polling - where the remote action returns HTML:

<saf:div href="mailbox.action?id=%{id}" updateFreq="2000"/>

Advanced usage of this tag includes adding a <script> block to the returned HTML. It will be executed when rendered, just like normal JavaScript is.

Tabbed pane is another component that's made up of two tags: <saf:tabbedPanel/> and <saf:panel/>. Rather than specifying content/tags within an <saf:panel>, to use the Ajax version, you simply add remote="true" and href="remoteUrl" to <saf:panel>. I asked about remote="true" being redundant and Patrick agreed it should be implied when an "href" attribute is defined.

SAF also includes the ability to have topic-based events. Dojo supports an event system, which was originally donated by the WebWork developers. Any element, such as a div, may listen to multiple topics. Any element, such as an href or tab header, may notify a topic.

The last thing that Patrick is demonstrating is Validation using DWR. To use it, you will need to use SAF's Ajax theme, as well as have DWR installed and configured. The remote calls to SAF's validation engine return serialized objects rather than HTML "partials". By default, it uses onBlur events to do the validation and all that's required on the client-side is validate="true" on your <saf:form>. Another cool Ajax feature that SAF has is an OGNL Console that gives you a command-line interface to evaluate OGNL expressions.

Patrick's lessons learned from implementing Ajax into WebWork/SAF:

• Simple combinations of the basics can create powerful features, such as the tabbed pane or the tree widget.
• JavaScript inside an HTML block (<saf:div>) or as returned from an action (<saf:a>) can provide valuable glue code.
• The <saf:div/> and <saf:action/> tag have a close and important relationship.
• Understand the important differences b/w Ajax styles (DOM-based vs. snippet-based). Both have their places.

Pitfalls:

• Remember: there is no silver bullet
• At the end of the day, your application is still a web site - don't forget that
• Excessive polling can lead to extreme load and/or thread starvation
• Common functionality, such as the back button and printing, can become difficult or confusing for the user (Dojo can help solve this problem)
• Browser incompatibility can lead to two versions of the same application (see GMail)

The Struts Team hopes to release a preview release of Struts Action 2.0 this week or next, with a final release targeted for August.

Heading to the Big Apple

May is shaping up to be quite the travel month. Next week I'm heading to New York City to put on a 5-day seminar for a client. Topics include: Web Frameworks, JSF, Ajax, Spring, Spring Web Flow, Hibernate, Caching and Performance, Deploying to Production, Comparing CMS Applications, eCommerce in Web Applications, Sharing with RSS and Atom, Acegi Security, Storing User Preferences, Source Control with Subversion and Coding Standards/Project Management. Yeah, a whole slew of stuff. There's nothing like doing a customized seminar when the client gets to pick whatever topics they like.

The only things I'm a little light on are Comparing CMS Applications, eCommerce and Storing User Preferences. For Comparing CMS Applications, I'm going to talk about Alfresco, Drupal, Joomla, Magnolia, OpenCMS and Plone. I'll be talking about ease of installation, ease of use, community and support, extensibility and performance. One thing I plan to do is zing CMS providers about eating their own dogood. As far as I can tell, neither Alfresco nor Magnolia use their own CMS for their websites. Of course, they might not be developing a "CMS for the web", but that's what most folks tend to use CMS's for IMO. It should be interesting to see if the Java solutions have decreased their installation times. Drupal, Joomla and Plone all took under a minute to install (on OS X) the last time I tried. If you happen to work on one of these applications and want to point out a kick-ass site developed with your software, please leave a comment.

As far as eCommerce solutions, most of the applications I've worked on recently just hook in with PayPal. This seems like the best solution because you eliminate the headache of credit card processing and in-house security/fraud preventation. If you've recently developed an e-commerce enabled application, what solution did you use? Did it work well for you? I'm also interested in solutions that were utter failures or a pain in the ass to use.

Lastly, as far as storing user preferences - I can only think of 3 ways to do it: cookies, database tables, and using the Java Preferences API. I'm sure I'm missing something. What solutions have worked well for you?

After returning from NYC, I'll be in Denver for 5 days before flying out to San Francisco for The Ajax Experience and JavaOne. In the midst of all the travel, I hope to finish up the CSS Design Contest, release Equinox 1.7/AppFuse 1.9.2 and do some performance tests with the T2000.

Good Parties at JavaOne

Are you going to JavaOne in a few weeks? If you are, you'll want to know all about the good parties. So far, I've heard the SolarMetric/Tangosol Party is Tuesday night, but don't know if it's been renamed to the BEA/Tangosol Party. I've heard same time, same place.

On Wednesday night, there's a GlassFish BOF at 5:00, a Struts BOF at 5:30 (in the pavilions) and our Geronimo Live Party from 6-9. You'll need to pre-register to get into the Geronimo Party. Luckily, you can easily do that by clicking on the image below.

The party is at the swanky W Hotel, which is right across the street from Moscone. It's sponsored by the following Geronimo Supporters:

Any other good parties you know of at JavaOne?

Gig in Seattle

I don't normally post gigs on this site, but I do when they're good rates, and the person hiring is a friend of mine. Here's one in the Pacific Northwest (Seattle):

• 5+ years of experience with Java and J2EE required including EJB, JMS, and JSP/Servlet, required.
• 3+ years of experience with UML, SOAP, XML/XSL, SQL, Struts.
• 1+ years experience working with external client on projects.
• Experience applying design patterns and OO best practices required.
• Experiencing writing use cases and producing design documentation required.
• Experience developing on Unix platforms required, preferably RedHat Linux.
• Required application experience: BEA Weblogic, Tomcat, Apache.
• Desirable application experience: Maven, Struts, Spring, MySQL, Oracle.
• Desirable methodology experience: Refactoring, Agile, Scrum.
• Desirable additional skills: WML, WAP, XHTML, XSL, XML Schema, SSL, HTTP, Perl.

Let me know if you're interested and I'll forward you the full job description and contact person's information.

Shale Remoting Library

Ed Burns on JSF AJAX Components:

These components leverage the Dojo Toolkit and make use of the JSF PhaseListener approach for serving up JavaScript files and handling AJAX requests on the JSF server. This approach was innovated by the Blueprints and JSF teams and generalized in the Shale Remoting library, which these components leverage to great effect.

Click on the Shale Remoting link to see the good stuff.

[ANN] AppFuse 1.9.1 Released

This release includes improvements and upgrades to Tapestry 4.0.1, WebWork 2.2.2, as well as support for using AppGen to reverse engineer database tables (using Middlegen). iBATIS is now supported by AppGen and a Create DAO tutorial has been put together for iBATIS. iBATIS and Middlegen support were provided by Bobby Diaz - thanks Bobby! Also, a big thanks goes to Mika Göckel for writing an XFire Tutorial and installer. To install and configure AppFuse for development, see the QuickStart Guide. Thanks to all the sponsors who have contributed products and free hosting to the AppFuse project.

• Download
• Release Notes
• Learn more about AppFuse

To see how AppFuse works, please see the following demos (username: mraible, password: tomcat):

• Demo of Features in Flash (needs to be updated, things are much easier now)
• Struts + Spring + Hibernate
• Spring + iBATIS
• WebWork + Spring + Hibernate
• JSF + Spring + Hibernate
• Tapestry + Spring + Hibernate

Comments and issues can be sent to the mailing list or posted to JIRA.

Tapestry 4.0 support in AppFuse's CVS

I spent the last couple of days upgrading AppFuse from Tapestry 3.0.3 to Tapestry 4.0.1. While the integration isn't as clean as I'd like it to be, everything works and all tests pass, so that's good. I did post a few remaining issues to the Tapestry mailing list, but there's nothing major. While the upgrade was frustrating (it took me 4 hours to figure out I needed "validators" instead of "validator"), I feel I know a fair bit more about Tapestry now. Furthermore, my experience on the Tapestry user mailing list was incredible. Yesterday, for every question I'd send, I'd get 2-3 replies in a matter of minutes. It was like having my own personal Tapestry consultant by my side. It goes to show that Tapestry is a thriving community, with a lot of folks willing to help out. Thanks guys - I really appreciate the help.

Update: You can view the FishEye Changelog to see what the upgrade entailed.

[TSSJS] Java Web Frameworks Sweet Spots BOF

I've finished composing my "Java Web Framework Sweet Spots" document and presentation for tonight's BOF at TSSJS. Unfortunately, the BOF is at 6:30 and Crazy Bob's wedding is at 6. So I won't be able to make it to the wedding, but I do hope to have a toast to Bob and his new bride. I have been successful in securing beer for the BOF, so you'd better get their early if you want a free one. Caesar's doesn't have kegs, so it's $6/beer and we've purchased 100 of them for attendees. After that, it turns into a cash bar. Thanks to Virtuas, Codehaus, SourceBeat and yours truly for pitching in for the free booze.

My presentation tonight will be short and sweet. Rather than going through each framework author's responses, I'm just going to highlight their "sweet spot" responses. This allows me to get away with creating a measly 8-page presentation, as well as have a more interactive session. I've taken everyone's responses to the 6 questions I asked, and compiled them in a document. This document is available on the Virtuas site, just click on the link below to download it.

» View Java Web Framework Sweet Spots

[TSSJS] Friday Morning: RIFE and Seam

This is my 2nd day in Vegas and so far this town is treating me fairly well. I haven't lost all of my money, but the $25/hand blackjack tables haven't been kind. Yesterday, I woke up with a glass full of Berocca next to my bed - which means I passed out before drinking it. I needed it too, Matt Filios won a poker tourney and a bunch of us enjoyed "bottle table" (with Kettle One vodka) to celebrate. Spendy and good, but painful the next day.

Last night, I heard it was Crazy Bob's bachelor party, so I went to bed early to avoid the debauchery. Julie and a good friend of mine are flying in tonight, so there will be plenty of that this evening. So after a good night's sleep, I'm up early and attending the conference. The first hour has a lot of good sessions: Introduction to Seam (Gavin), Dive into RIFE (Geert), OSWorkflow (Hani) and Transforming Enterprise Java into a Commodity (Geir).

I'm sitting in Geert Bevin's session titled "Dive into RIFE" and it's a pretty small audience - maybe 20 people. Geert is the CTO of Uwyn, a small custom application development company. He's the founder of RIFE and creator of many RIFE projects: RIFE/Crud, RIFE/Jumpstart, RIFE/Continuations, Bamboo (forum), Bla-bla List (RIA todo list), Drone (Information bot) and Elephant (blog).

What is RIFE? It's a full-stack component framework to quickly and consistently develop and maintain Java web applications.

• Integrated layers allow you to quickly get results with a minimal amount of code
• Best practices are enforced in a pleasant way, providing many additional features and a consistent approach throughout all applications
• Components can easily be resused in many contexts
• Creating maintainable applications is our first goal
• A lot of attention goes to code-level developer comfort
• Frustration reduction by instant changes and reloads
• Creative solutions for difficult problems
• Embraces established standards (XHTML, HTTP, SQL, ...)
• Geared to developing web applications and doesn't abstract away too much
• Everything besides the web engine is designed to be independently usable
• Attention to the whole life-cycle of your application

Geer is now talking about all the different pieces of RIFE - how it has a JDBC abstraction like Spring JDBC, web services support (even publishing of RSS Feeds) and a content management framework. Now we're going to look at RIFE/Jumpstart.

What is RIFE/Jumpstart? It's a source archive that you unzip and run. It makes it easy to start with new RIFE applications and contains everything you need (including Jetty). It has immediate support for more common development environments (X-develop, Netbeans, Eclipse, IDEA and Ant). Geert just showed us a video of getting started with Jumpstart and how you can easily use X-develop to build and deploy the app to Jetty. The Jumpstart application currently uses JUnit, but since the RIFE teams is starting to use TestNG more and more, it's likely they'll change in the near future. RIFE Jumpstart looks similar to AppFuse, except they have the save+reload problem solved - using JVM HotSwapping.

Now I've moved to the Introduction to Seam session. Gavin King is the presenter and the room is packed. It's a big room, so that's saying a lot. Gavin is talking about JSF, how backing beans work and what's in the faces-config.xml. How does Seam compare to J2EE? Much simpler code. There's fewer artifacts (no DTOs). Less noise (EJB boilerplate, Struts boilerplate). More transparent (no direct calls to HttpSession or HttpRequest). It's also much more powerful for complex problems.

JSF is amazingly flexible and extensive. EJB interceptors support a kind of "AOP lite" and EJB3 is a powerful ORM engine. Everything (except for the JSP pages) is unit testable can be tested with JUnit or TestNG. For testing the view layer, Gavin recommends using Selenium.

A backing bean is often "pure glue" and is just noise. Furthermore, it accounts for more LOC than any other component. It doesn't really decouple layers, in fact the couple is more coupled than it otherwise would be. Gavin calls this "wedding cake architecture." These applications look good in the window, but don't taste good when you eat them. I get his point, but have to disagree on the taste of wedding cake. It's always been good at the wedding's I've attended. ;-)

By default, web applications in general do not work in a multi-window application. To make it work, it generally requires a major architecture change. A couple of other areas for improvement in traditional web applications: application leaks memory (not cleaning up session objects) and "flow" is weakly defined. Navigation rules are totally ad hoc and difficult to visualize. How can this code be aware of the long-running business process?

JBoss Seam - what does it do? It unifies the EJB3 and JSF component models. It simplifies Java EE 5, filling a gap. In addition, it integrates jBPM and makes it more developer-friendly. Deprecate so-called stateless architecture. Decouple the technology from the execution environment. Run EJB3 apps in Tomcat or in TestNG or use Seam with JavaBeans and Hibernate. Gavin is using Tomcat for the first time and thinks it's hot-deploy architecture is totally broken. Of course, he usually uses JBoss and never has a problem with hot-deploy. It's interesting to hear this from Gavin, especially since I've heard from others that Hibernate breaks the reloading - and it's not the server's fault.

I'm going to head to another session now, but I did look ahead at some of Gavin's slides. Interestingly enough, the jPBM pageflow definition's XML looks quite similar to Spring Web Flow. Speaking of flows, I heard an interesting comments from someone yesterday after they attended Geert's continuations talk. Apparently, after seeing his talk, they think that RIFE's continuations offer a much more elegant solution to pageflow than these "XML programming" mechanisms.

I tried to go to Hani's OSWorkflow talk, but he was doing Q&A when I walked in. Apparently, he finished 25 minutes early. Then I walked into Geir's talk only to find Dan Deiphouse finishing up an XFire talk. Oh well, there's nothing wrong with having a few minutes to mingle between talks.

Using JasperReports with AppFuse and Spring MVC

It's been over a year since Gilberto wrote a message to the mailing list about how to use JasperReports with AppFuse's Spring MVC flavor. Now he's created a tutorial for how to use JasperReports in AppFuse. Thanks Gilberto!

I've seen a fair amount of howtos for Spring MVC + JasperReports. I've even written one myself as part of Chapter 6.5 in Spring Live. However, I haven't seen many articles detailing how to integrate JasperReports with other Java web frameworks. Are they out there and I'm just not seeing them? It'd be great if we could show how to integrate JasperReports with all the web frameworks that AppFuse supports.