More mention of YAML by Kendall Grant Clark.
Weblogs are important part of Java.net although one needs to stroll around a bit to find them. I usually go here to find new articles. Here are two articles worthy of mention this week:
In Whats up with the JavaSound team?, Jonathan Simon discovers that entire JavaSound team split a while back and now there is just one hardworking guy wearing many hats.
This is ridiculous on a number of levels! How does Sun expect to put out a decent product with a single guy responsible for all of JavaSound? Also, the code was poorly designed to begin with, and Florian can't even really change it! So whats left is a really buggy, poorly designed library that is on every Java enabled PC!
Michael Champion, an old compadre from XML-DEV, answers the question "When does SOAP add value over simple HTTP+XML?" and concludes with:
It's just as "wrong" to blindly reject SOAP as to blindly accept. it.
Right on, Michael.
I spent a few hours last night playing with Laszlo and liked what I saw. Laszlo address many Flash shortcomings, allowing programmers to use Flash as front-end for web-based enterprise software without dealing with all the mess that has piled on top of Flash all these years. Having spent a lot of time on a similar idea, I know that what they have accomplished is an impressive feat. Frankly, I don't think I could have designed it any better.
Laszlo pulls together many open source Java packages such as:
- Axis - for web services
- Batik - for SVG support
- FOP - for XSL-FO support
- JDOM - for simplified DOM manipulation
- JGenerator - for SWF generation
- Jing - for RELAX NG validation
- JXPath - for XPath support used to select dataset nodes
- Jython - don't know what for yet (it's Python on Java)
- OpenOffice - probably for OpenOffice file format support
- Xerces/Xalan - for XML parsing, DOM, and XSLT
- XPP3 - an implementation of XmlPull API
Laszlo can be most readily integrated with J2EE applications because it is entirely Java-based and LZX, Laszlo's XML-based Flash UI description format, can be generated easily with JSP. Following diagram shows how this works:
Hello.html is just a static page that embeds a movie returned by Hello.jsp. Browser loads Hello.html which causes the Flash plugin to fetch a movie from Hello.jsp. Hello.jsp emits LZX, instead of HTML, which is used by Laszlo to generate and return SWF. With minimal efforts, other control flow can be used and processes can be added (i.e. XSLT) as long as LZX is fed into Laszlo in the end. Neat.
There are, however, some issues with Laszlo that affect developerment and user experiences.
First, LZX to SWT conversion takes a while, much longer than JSP compilation. Add up everything and you got enough delay to affect development experience.
Second, a Laszlo-based webpage is slower to load than DHTML-based webpages. This is understandable because a Laszlo-based webpage can handles a lot more interactions with the user before having to reach out to the server than a DHTML-based webpage. Still, the delay is noticeable enough to affect user experience.
Third, browser integration problems with full Flash-based webpages are still there. For example, pressing the Browser's Back button will not work properly. There are other similar issues that must be addressed soon.
There is much I like about Laszlo, particularly the power of LZX. LZX's extensibility is impressive. I need to spend a few more hours later to look deeper under the hood, but what I like about Laszlo are these:
- Harmonized with Java-based web applications - you write your backend in Java and drive Laszlo using LZX tags from JSP. This allows you to leverage your existing investment in Java.
- Smart use of Flash - you still need Flash to generate graphics and animation resources used by LZX tags. This means Flash developers in your team can focus on what they know best.
- Good People - I am impressed by the talents behind Laszlo.
[Sorry about the shitty diagram. I could have used Visio, but I also needed more lazy learning time with GraphViz. Since I still don't know enough about dot to generate good looking diagrams, result is what you see above.]
I had been expecting baby talk versions of complex XML formats to emerge for sometime now. It hasn't happened yet so I am left with scratching my head. The idea is simple enough, take a complex format and create a user-friendly version that maps to the more complex version via an XSLT file.
When I am onto something, it is difficult to let go. Laszlo has been on my mind all day. Here are some thoughts on improving Laszlo:
Laszlo IDE
Laszlo needs an IDE. Currently people are expected to use whatever editor they have to edit LZX files. Eclipse is the best IDE technology out there, so integrating Laszlo with Eclipse makes sense.
Faster LZX Compiler
Engineers should not have to wait to see the result of changes they made during development, particularly at presentation level. I don't know why LZX compilation seem so slow, but this must be fixed ASAP. Here are some options:
- Compile Laszlo and JGenerator to native code
- Incremental LZX compilation
- Finer-grained SWF generation and caching
- Client-side weaving of SWF fragments
Wizards
Provide wizards to ease common tasks and solve common issues such as Page Back and Browser Resize problems.
By nature, I am enthusiastic and generous with complements as well as criticisms. So it is understandable for some of my readers to think my recent posts on Laszlo are outright recommendations for Laszlo. They are not. I thought I should make this clear before the confuson spreads any further.
What I have written before are what an excitable traveller might have said while touring through Three Gorges or Grand Canyon. This post is what the traveller might have said at the end of the trip, in response to the question "Would you want to live here?"
In short, my answer is no. I will have to post the longer version later, but my answer has a lot to do with why I decided not to pursue an idea similar to Laszlo while back.
I apologize if I confused you. I believe in simplicity, but I am far from being a simple person.
