Raible Designs

My Job for the next couple of weeks

I can't help but brag about how cool my current gig is with Open Logic. My task for the next few weeks is to write a simple sample app - and create alternative MVC implementations. Targeted frameworks include Struts, Spring MVC, WebWork, Tapestry and JSF. Not only am I working from home, but they dropped off an AMD XP 2800 to work with. Installing Fedora Core 2 with VMWare is what I'm up to this morning. Working with open source all day - it doesn't get much better than this.

Rendezvous for Windows, can be called from Java

Rendezvous rocks on the Mac. Wouldn't it be nice if you could use it between platforms or even in your Java apps? You will be able to shortly...

Apple released a developer's preview of Rendezvous Networking for Windows 2000 & XP at wwdc 04. ... Also released was support for various POSIX platforms, including Linux, Solaris, and FreeBSD, as well as making it callable from Java. [MacRumors]

JSF can mimic Tapestry?

According to this article, JSF can do everything Tapestry does. Of course, there's a discussion on TheServerSide.com - and it's worthless so far. Hopefully some Tapestry users will chime in and we'll get some real feedback. IMO, this shows that JSF might have some real power - what's stopping it from mimicing other frameworks' favorite view technologies?

[NFJS Denver] David Geary and Advanced JSF

David is going to cover some JSF advanced topics: data table, tiles integration, custom components and validators. I was talking with Rick Hightower last night. He mentioned that he's been doing a fair amount of work with JSF lately and really likes it. He actually said he thinks he can develop a webapp faster with JSF than he can with Struts. He also said that JSF ships with a lot of what you need - and a lot of the JSF books seem to cover how to add new stuff (custom components and validators) you don't need. This is to say that the books tend to cover the features of JSF, rather than how to develop successful projects with JSF. I said I thought it'd be nice if there were some JSF books by folks who'd used it to deliver applications. More of a "here's what you need to know" kindof manual. I think that's what JSF needs.

The <h:dataTable> in JSF is pretty much the same as the <c:forEach> tag in JSTL. An interesting note on the JSF expression language - it starts with a # instead of a $. For example:

<h:dataTable value='#{tableData.names}' var='name'>
...
</h:dataTable>

The major difference between JSF and JSTL's expression language is that JSF EL can access managed beans. The JSP 2.0, JSTL and JSF expert groups are going to work together to try and synch up their expression languages. Personally, I don't see why the JSF folks didn't just use JSTL and simply include managed beans in the lookup logic. Here's a wierd one - if you use any "template text", i.e. in a dataTable - you have to wrap the text with <f:verbatim>text</f:verbatim>. David says this is one of the embarrasing things about JSF. He hopes it'll be fixed in the next version.

The <h:dataTable> looks very similar to the DisplayTag. Sweet - that's one less thing I'll have to worry about when creating a JSF app. I've said it before and I'll say it again - my two favorite tag libraries are the DisplayTag and Struts Menu. As I'm learning new frameworks, one of my major goals is to reproduce the same functionality I enjoy in my Struts+JSP apps. It's been pretty simple so far with Spring and WebWork, since both support JSP. However, it might get a bit tricky with Tapestry and JSF. I'm sure it'll be possible (and hopefully easier) to reproduce this functionality, it's just a big unknown at this time.

"Form" beans in JSF are not like form beans in Struts. It's really just a class that doesn't extend anything and has action handler methods. An interesting point - the actionListener's value (which is really a class.methodName) can be any class in any scope OR it can be a managed bean. How about some code:

public class Form { 
    public void changeLocale(ActionEvent e) { 
        FacesContext context = FacesContext.getCurrentInstance(); 
        Map requestParams = context.getExternalContext(). 
                            getRequestParameterMap(); 
        String locale = (String) requestParams.get("locale"); 
        if ("english".equals(locale)) { 
            context.getViewRoot().setLocale(Locale.UK); 
        } else if ("german".equals(locale)) { 
            context.getViewRoot().setLocale(Locale.GERMANY); 
        } 
    } 
}

The major reason behind the FacesContext is to support Portlets. So rather than using a ServletContext or PortletContext, the FacesContext provides a level of abstraction. The underlying theme of JSF: To be as flexible as possible. This is to say that there are many ways to do things with JSF. I often think it's better to have less choices when learning a technology, but once you're versed in it - choices are great. I guess I just wanna know the best way to do things, not all the options. Actions are for business logic, ActionListeners are for UI logic. ActionListeners are always fired before Actions - in the event that you have an actionListener and an action defined for the same component. Listeners and Actions are really just methods on a class and they can actually both be in the same class. JSF is starting to appeal to me. This session has been one of the fastest so far - there's only 20 minutes left and it feels like it's flown by.

JSF ships with converters for dates and currencies out-of-the-box - cool! Now David is explaining about a custom CreditCard converter. This is what Rick was talking about last night. Why do we need to know this stuff? Would a normal talk on another MVC Framework talk about converters and validation? I bet not. I think it's a good topic - maybe something that other frameworks should cover more visibly. The Converter interface has two methods: Object getAsObject() and String getAsString(). The Validator interface has one method: void validate(FacesContext context, UIComponent c). I just asked David about using Commons Validator instead of JSF's core validator. He said, "Yes, it's possible." Sweet! You can use Commons Validator with Struts, JSF and Spring! Now if we could only get support for it in WebWork and Tapestry - then I'd eliminate my need to learn another validation engine.

Now David is talking about using Tiles with JSF. It looks as simple as using the <tiles:insert> tag to insert dynamic content into an <f:subview>. Any time you insert a tiles component, you need to wrap it in an <f:subview> tag. That was short - we're done talking about Tiles. I had some questions - i.e. can you refer to a definition directly from an action or in the action's navigation definition? Oh well, onto custom components and renderers. Custom components and renderers seems to me to be something that should be left out of these types of presentations. Sure, it's cool they're possible - but who's using them? Have you needed them in a real-world JSF application? I only want to know the things I need to know to develop a real-world JSF webapp. Sorry, I forgot - there aren't any real-world webapps written with JSF. If I'm wrong - send me a link. ;-)

This presentation was good - it inspires me to learn some more about JSF. Maybe there'll be some projects in my next gig that require JSF - that would be wicked cool. After all, the best way to learn this stuff is to get paid to do it. If nothing else, I'll get to learn it later this year when I write AppFuse's web layer in JSF.

[NFJS Denver] Ramnivas Ladded and Aspect Oriented Programming

For the 2nd session of the day, I've decided to attend the session on AOP. My choices were Converting XML (Ben Galbraith), JSF (David Geary), What's new in EJB 2.1 (Monson-Haefel) and Runtime Code Generation (Glenn Vanderburg). I asked David about his JSF presentation and he said it was "boring" so I decided to skip it. This session, in the first 10 minutes, is pretty boring too. I might have to duck out of this and attend another session - but none of the other sessions really interest me. This one started this morning, and it seems to be a continuation of this morning session. It's mostly on AspectJ and he's doing the good ol' logging example. I don't really have an interest in using AspectJ since Spring's AOP is more than adequate for my needs. Oh well, I guess I'll stick around and relax.

Ramnivas is using Eclipse to compile his aspects, and shows us how if he uses "javac" to compile everything, no aspects are added. I'm guessing that there's some sort of plugin for Eclipse that allows for easy compiling of aspects. A new feature in AspectJ 1.2 is the ability to set an ASPECTPATH and then use "aj" rather than "java" to run code. This achieves the same effect as compiling the aspects in Eclipse. The "aj" script appears to just set the system classloader.

Now Ramnivas is showing us how you can use an aspect to define pointcuts on internal appserver classes. His example involves WebLogic, the J2EE Petstore and logging any EJB method calls. To use this, he has to start WebLogic with a custom script, that has a custom classloader defined. For some reason, we're now talking about log.debug() vs. if (log.isDebugEnabled()) { log.debug() }. Ramnivas thinks that most folks don't wrap their debug statements (the proper way). Who doesn't know about this?! I'd like to think that most developers are writing the 3-line version vs. the 1-line version.

An interesting quote: "So many things to show you - 3 hours is not enough." Maybe if we didn't have to wait 2 minutes for WebLogic to start each time, 3 hours would be plenty. ;-) Ramnivas just added logging to all the classes in the blueprints packages and then reloaded the page. There looks to be several thousand method calls occurring behind the scenes for a simple page. Of course, there's lots of tag libraries - but still - PetStore is a ridiculously complex application. Why did some ever impose this crap upon us as "best practices" for Java. IMO, best practices should be based around simplicity, maintainability, testability and performance. Does the PetStore even ship with unit tests? I'll bet it doesn't...

Now we're watching a pretty cool demo where Ramnivas is using aspects to enforce coding policies. In this example, he's using aspects to enforce rules in EJBs (i.e. no static variables, swing or threads). It interesting in that the aspects actually prevent compilation and display errors defined in the aspect. It's a neat idea, but I'm suspicious in that a lot of this AspectJ stuff seems to be Eclipse-specific. What I mean by this is that Eclipse seems to be required for compilation. Is it easy to aspect-enhance your classes using Ant? I would hope so.

Ramnivas seems to be quite the AspectJ expert. He mentioned that he wrote a book for Manning and has mentioned a couple of his contributions to AspectJ in this presentation. I admire authors that write and contribute to projects at the same time. It's often an indicator that the person knows what the hell they're talking about.

This afternoon's first session choices are as follows: JSF Advanced Topics (Geary), Intro to J2EE Web Services (Monson-Haefel), JSR166 (Glenn Vanderburg), Rhythm (Brian Boelsterli) and GUI Development (Ben Galbraith). Web Services and Rhythm are 3 hour presentations, so I might stay away from those - that's just too long for me. Now that I'm sitting in the 2nd half of a 3 hour presentation - it seems that these sessions are best attended in the first half. It's almost as if the presenter is trying to find things to talk about in the second half. Or maybe AOP is just a boring-ass topic. ;-)

I'd like to go to Brian's talk on Rhythm, since he's a good friend and mentor of mine. But then again, I learned Rhythm from him - and use it daily - so I don't know that I'd get anything out of it. Advanced JSF looks good, maybe I'll go to that one. For the 2nd session this afternoon, I'll probably attend Howard's Creating Powerful Web Forms with Tapestry. Maybe I should stick with JSF and Tapestry and make it a web-intensive afternoon. Both presentations are even in the same room!

[NFJS Denver] Mike Clark and Continuous Performance Testing

I'm sitting in Mike Clark's Continuous Performance Testing talk right now and he's telling us about his experience with performance optimization. Unfortunately, there's wireless access in this hotel's lobby, but not in the (small) rooms. This post is being sponsored by Bluetooth and my T68i. There's two traditional methods of performance tuning - pre-optimization and after-the-fact. He's pointing out that it's most important to have well-factored code - then when you do decide to do performance optimization, it's simply easier to do.

I had lunch with Bruce and Rod Cope (my new boss) has joined us in this talk. It's cool to be engrossed in Java with my friends and peers. Choices for this first session included: EJB CMP, JDO and Hibernate (Bruce Tate), JSF (David Geary), Naked Object (Dave Thomas), Continuous Performance Testing (Mike Clark) and Practical J2EE Security (Tom Marrs).

Back to the talk - Mike is talking about JUnitPerf and how it works. JUnitPerf looks pretty easy to use, below is a simple test.

Looks pretty simple huh? I'm assuming that the Test and TimedTest classes are part of JUnitPerf. Next up - Profilers. Use a profiler when your performance tests fail. Low tech profiling (we've all done this) - using System.out.println with a variable and some math that prints out how long it took for a method to run. Even better - using a "Profiler" utility class that does that math for you and has start() and end() methods. Medium-Tech Profiling - JVMPI using -Xhrunprof. It spews out a whole bunch of information so you can see how long methods take to run. The problem with it? It spits out ALL the information from the JVM and your class/methods end up at the bottom of the stack. Sounds like too much information for me. Mike's take: hprof is a sledgehammer that is basically unusable in a J2EE environment. In JDK 1.5, JVMPI is going to go away and it will be replaced with JVMTI (Tool Interface). He also mentions JFluid and Dynamic Bytecode Generation

High-Tech Profiling: JProfiler, OptimizeIt, JProbe - all of which use JVMPI. Mike likes JProfile b/c it's cheap and recommends looking at javaperformancetuning.com for open source tools.

Performance Testing Cycle

• Choose a measurable performance goal
• Write an automated performance test
• Run the test to baseline performance
• Profile the code to identify hot spots
• Tune one thing
• Run the test again to measure progress
• Repeat until performance goals are met

As I blog Mike's presentation, I'm starting to realize there's probably not much point to doing what I'm doing - regurgitating his presentation on the web. A better way to "blog this" event (IMO) would be if I could merely provide my thoughts and comments about each presentation I attend. The presenters will certainly get more out of it, and readers will probably enjoy the post more. But that's the hard part. It's easy to blog as a presenter speaks - but it's hard to formulate your thoughts and opinion as they speak. It's easy to blog your thoughts after the fact, but that's supposed to be the best part of NFJS - the hallway conversations b/w sessions. I could miss the first 10-15 minutes of each new presentation writing about the old one, but that's no fun either. I guess I just need to start thinking faster, formulating my opinions as fast as possible and writing them down. From now on, I'm going to try to refrain from regurgitation and go more for opinionated reporting. Is that what you'd prefer? If my readers want regurgitation, I can continue that route - I just think it makes for boring entries.

Man, these are long sessions. I just looked at the schedule and all the talks today are 1 1/2 hours! That's too long IMO. I'd loathe it as a speaker and as an attendee - I'd prefer 45-60 minute presentations. Mike's a good speaker, but it's tough to keep anyone's attention for more than an hour - unless it's something like soft core porn.

Choices for the next session are: Programming with Hibernate (Tate), Rapid UI Development (Geary), OpenSource Ecosystems (Thomas), Java Classworking (Dennis Sosnoski) and Getting Fit (Daniel Steinberg). I'm leaning towards Rapid UI Development or OpenSource Ecosystems.

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!

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?

My Review of Java Studio Creator (a.k.a. Rave)

I attended a Rave Demo at Sun in Broomfield today. The meeting actually had two parts - the first hour was a marketing schpeel about Sun's Enterprise Java System and the second hour was a demo of Java Studio Creator. The first hour was boring and very marketing esque - they did have an interesting price point though - $100 per employee. This is small business friendly, which is nice to see.

The Rave (a.k.a. Java Studio Creator) Demo was when things got good. Here's my notes from Dan Robert's presentation, followed by my impressions and comments. Dan is the Product Manager for JSC and was seemed to be very in tune with the tools marketing (i.e. all the good stuff from Intellij and Eclipse - and how JBuilder sucks).

What is it?

• New Java Development Tools initiative
  • For the corporate developers who write code, but don't understand all of the complexity of J2EE and just need to get their job done.
• A full fledged Java IDE
  • Visual Design Tools, 2-way editing, Editor, Debugger, Repository Management, and Project Management
  • Cool new Look and Feel
• Complementary to NetBeans and Java Studio
  • Even Enterprise developers can use it for Rapid Prototyping
  • Use Java Studio or any other tool to add persistence layers (heh, this is b/c they think that persistence can only be EJBs ;-))

What does it do?

• Quickly builds web applications that solve time-critical, real world problems
  • Complete web application creation for departments, workgroups and businesses of all sizes
  • Focus on easy to understand, event driven coding model
  • Simplifies access to existing infrastructure
  • All Java-standards based servers, all databases, all Web services, all desktops
  • Their main goal is to do web applications well, they'll catch up with the rest later

Standards-based solution for all developers

• A development solution based on 100% Java standards
• Delivers "Write Once, Run Anywhere"^TM benefits: portable apps, portable developer skillsets
• Quickly solves time-critical app development needs
  • Drag and Drop, rapid visual access to databasess and web services
  • consistent UI look/feel/behavior across all apps

Visual features to speed development

• Palette for widgets, custom graphics, code clips, etc...
• Query Editor

Simplified Access to Existing infrastructure

• Use any JDBC Compliant Database (3.0)
  • Drag in and automatically create DB connections to data-aware components
• Web Service Consumption
  • Easily pull in existing web services from Enterprise wide solutions or business partners

Java Studio Creator Roadmap

• Hammerhead:
  • 2-tier dynamic content web applications based on JSP and JSF with Page Flow design tools
  • Releases: Early Access Spring 04 (today!), FCS Summer 04 (at JavaOne)
• Thresher:
  • Minor Update Release
  • Focuses on Ease of Development and Stability
• Mako
  • Extended Client Support

Download today from http://www.sun.com/jscreator. OS X version will be available shortly after the release (JavaOne).

After the PowerPoint, Dan started into the Demo. The first thing I saw that was cool was that when he clicked on the "Run" button, it actually deploys the app and opens the browser to run it. What you see in the browser looks very similar to what you see in the IDE. The IDE looks very simple. My current client went with me and he remarked that it "looks a lot like Eclipse."

The IDE has lots of palettes, and the UI essentially looks very clean. The pallets can be docked just like in IDEA - which I like. It looks a lot more like a native Windows application than it does like Swing. Here are the palettes it has:

• Server Navigator
  • Data Sources
  • Web Services
  • Deployment Servers Palette
• User Defined
  • JSF Standard Components
  • JSF Validators / Converters
• Property Sheet
• Project Navigator

Dan then dragged a drop down component and a table component onto the page. Secondly, he added a stylesheet and it visually changed the background and fonts on the page. I asked him if there was an imbedded browser. He said they took a look at using Mozilla, but it was too much and apparently one of the "real smart" engineers wrote the embedded browser component from scratch. Dan said it was the same guy who wrote the demo from scratch in 2 minutes at JavaOne last year. The thing I found very cool was that the HTML that is written into the JSP is XHTML - none of this Netscape 4.x support. Fuck Netscape 4.x - I'm glad Sun had the foresight to drop support for it.

After adding the stylesheet, Dan used the Data Sources navigator to grab a table and drag it to the drop-down. Then he did the same for another table and the data grid. Using the Visual SQL Query Builder (which looks a lot like M$ Access) he linked two tables and added a new column from a 2nd table to the grid. He then showed us that JSC has pretty good support for 2-way editing. Edit the code, the visual representation changes. Edit the visual, the code changes. This seems to be a big problem with WYSIWIG editors, especially when it comes to dynamic webapps. It appears that they've done a pretty good job to solve this.

Next he showed us some cool features of the components. For the table, there is an "enable paging" checkbox - and for the drop-down, you can right-click and select "auto-submit on change." He then set a couple of converter types on the drop-down and had to hand-code the event handler for the drop-down. Two lines of very simple code and he was done. The code was simple enough that you could have guessed the syntax. Code completion popped up nicely as well. Apparently the JSF coding style is that each page (JSP) is backed by a Bean that contains different event handlers. The code looked pretty simple and all the data was retrieved via RowSets.

Bill Dudney was there and asked about testing tools (i.e. Cactus or JUnit). Dan's response was that these are usually used by more advanced Java developers and there's talk of it, but nothing has been done yet. Now he pulls up a very cool page navigation creator which he uses to drag and drop buttons and links to point to different pages. Then someone asked about cost - and here's what makes it great. Under $300. They also hope to have lots of add on components for JSF by JavaOne. Unfortunately, there's no tooling for building JSF components in Java Studio Creator. For more information checkout http://developers.sun.com/jscreator.

The main reason I really like Java Studio Creator was that you literally never had to see any JSF code - and you get all of the features I like to use in webapps. Furthermore, I've been training a couple of guys all week on JSPs and using JSTL's SQL tags to do CRUD on a database table. While it's simple stuff, since they've never done web development before, it's a bit advanced. I'm sure their eyes will glaze over tomorrow when I start showing them how to write JUnit Tests, DAOs and how to use Hibernate to CRUD an object. They'll probably fall asleep by the time I show them how to wire the DAOs to Hibernate using Spring. When they saw this demo today - there eyes lit up and they got inspired to do their projects again. It looks easy for them now. All they need is a JDBC 3.0 driver for DB2 and they should be able to rapidly develop webapps with Java Studio Creator. I don't blame them for wanting to use this tool - it greatly simplifies things.

After the meeting, I asked Dan about transactions and if it was possible to use Hibernate instead of the RowSet stuff. He said that since JSC is based on NetBeans, you could probably write a plugin to use Hibernate instead of RowSets. As far as I know, the main reason you'd use Hibernate is for caching - but rowsets probably have that too. I know that the spec lead for JSF is talking to the Spring developers about JSF-Spring integration, so maybe that will be a future option as well.

Another thing that's not currently supported is the use of great technologies like Tiles or Sitemesh. Sitemesh integration would likely be pretty easy - you'd just never see your decorated UI in the IDE. Tiles is definitely something on the roadmap, but they don't have a solution yet. Dan indicated that using "includes" in your JSPs should work just fine - rendering in the IDE as they would in your browser. Good stuff - I hope we start using it at my current project - I think it'll do wonders for productivity. Since it's based on standards (JSF and RowSets) - the generated code looked pretty clean too.

WebLogic Workshop's NetUI and Page Flow

FYI...

April Denver BEA User's Group Meeting

Tuesday April 6th 6:00pm
Tattered Cover Down Town
1628 16th Street
Denver, CO, 80202

This months meeting will focus on WebLogic Workshop's NetUI and Page Flow technology that is built on top of Struts. We have a special treat in that Eddie O'Neal who is the BEA Engineering technical lead on NetUI and Page Flow is comming to talk with us. The primary discussion will focus on Weblogic Workshop and NetUI technology which is built on top of Struts 1.1. We will look a how these two relate and talk about the additional features NetUI provides on top of Struts like the additions to the programming model and the richer data binding. We will also look at a Struts variation of the petstore application that was migrated to a Page Flow.

AGENDA

5:30 - 6:00 Registration, Networking, Refreshments
6:00 - 7:00 WebLogic Workshop NetUI and Page Flow - Edie O'Neal
7:00 - 8:00 Field Secrets the next installation - John Funk
8:00 - 9:00 Further discussion at the Wynkoop Brewery and Raffles

Technology followed by beer is always a good thing!