Eitan Suez's Blog

June 2003 Archives

.. on TS-1521: Doing serious Java technology development on Mac OS X

A very good presentation full of lots of little demos. Clearly shows that developers have a variety of choices for development tools and utilities on the OS X platform. The turnout was great; Esplanade 304 room was practically full.

So, kudos for Apple and for their support of Java, and to the speaker for the great presentation. I've been running OS X on a TiBook for a little over six months now. I'm quite satisfied, though I'll still take the opportunity to ask for even more support for "mouse-free" development and consistency of shortcuts across applications.

TS-2312: Model 2X: The best of both worlds!

TS-2312 introduces the idea of combining jsp/jstl with xslt transformations to produce dynamic apps that target different markup languages, such as wml, html (why didn't they mention xul? i find it a shame that so far most people have blissfully ignored xul, a very powerful markup language for describing user interfaces..). so this Model 2X is the idea of pipelining processes (similar to cocoon) for rendering a ui (let's say a page), specifically by starting with a jsp "transform", followed by an xslt transform. the jsp's of course introduce the dynamic aspects of the page, but it produces a format-neutral xml result. this xml is then transformed using xslt to introduce the target-client-specific markup: html for [old and boring] web browsers, wml for small wireless devices [, and xul for cool modern web browsers].

so a problem i see here is both transforms must take place on every request. sure, you can parse the xslt stylesheet once and cache it. that'll improve performance. but why not reverse the order of the transformations? this could allow us to produce the target-client-specific jsp's at design time, not at runtime. that leaves a single transform at runtime.

so the only question left to answer: how de we fit x-query into the pipeline? :) the basic offer i've heard so far is xquery + xslt. so will xquery displace jsp??

Patterns independent of scale: the pull model

i'm sitting and listening to the TS-1560 technical session on the ws-i basic profile. we're looking at a diagram of a sample application: consumers pulling goods from a retailer shelf, in turn triggering the retailer to pull inventory items from a warehouse. inventory levels reaching a minimum threshold then signal manufacturers to increase production of a specific item to replenish inventories.

suddenly it strikes me: at an entirely different scale and domain, we see online users making http requests against servers. but typically what we see there is a push model: the http server pushes the request to an application server which then requests information from a database server. applying our pattern from the world of manufacturing where a good is pulled from manufacturer to consumer, we see a more natural solution:

an end user makes an information request, the http server is the retailer; it can satisfy that request if its cache (inventory) contains the item (though caches don't typically get low, they do often get stale, similar to consumer goods). the cache saves an expensive trip to the warehouse.

what if instead of pushing the request to the app server, we were to post the request to a javaspace or a jms server. then workers (manufacturers) could pull the items off the space (or queue) and service the request. so what we see here is the same pattern manifesting itself at two levels of scale. analyzing the solution further we can see it's a good one, because it naturally supports issues such as the ability of the system to serve larger numbers of requests by simply adding workers, without having to revise the "design." it's still the same pattern. we can make more inferences too in terms of the natural resilience of such a solution: if a worker dies the system is still running; if one worker is "more able" than another, it will naturally pull proportionally more requests than its fellow worker.

so the fit is natural, organic almost. and we say that it is good. :)

the morals that i'd like to suggest as they pertain to javaone are and the sessions i've attended this morning (which were TS-1624 [delegating jfc data models to collections], TS-1381 [an intro to jini] and TS-1560 [ws-i basic profile]):

• attend as many sessions as you can: they will trigger all kinds of thoughts and ideas (if you're like me, write them down before they vanish from short-term memory)
• look for synergies possibly emerging from combining various technologies
• if you haven't done so yet, read "the timeless way" (this book is not about software development, but applies quite well to software development)
• if like me, you "have not had the time" to take a good look at jini, i recommend it very highly. jini is one of those "substance over hype" value propositions, and embodies simplicity.

it's good to be here..

While awaiting the keynote on Wednesday morning, looking around me I noticed only a few yards away James Gosling having a conversation with a few friends, Tim O'Reilly standing maybe 2-3 yards away from him holding a separate discussion. Across the hallway there's Blake Stone from Borland typing away on his notebook computer. Can't help but feel: it's good to be here.

The Top 25 JUG Contest

so sun announced a few weeks ago a contest to find the top 25 java user groups in the world. i'm very excited about this announcement and have high hopes for my jug, the austin java users group (texas). we have a vibrant community that gets together monthly to attend technical talks, hold discussions on various technologies which usually last til midnight.

i'm really excited about the austinjug's membership numbers as listed on the sun site which currently is 110 (see http://servlet.java.sun.com/jugs/north_america/usa/texas/austin ) which appears to be the highest membership count i could find. so in all subjectivity, i await with anticipation the results of this contest (due sunday night) and hope that the top jugs get their due exposure during javaone this week.

The JavaOne Experience: attending sessions, meeting friends, and more.

javaone to me has become more than attending a marathon of sessions from dusk to dawn. it's a forum for meeting with one's peer face to face, for discussions and exchange of information. i was pleasantly surprised to find out that finding someone among the crowd this year is not as difficult as it used to be. i'd say the size of the conference (though still quite large) is definitely more enjoyable this year.

i've run into acquaintances from "back home" in austin (dr richard cohen whom i recently met at the austin xml users group), fellow speakers from other conferences (primarily the no-fluff-just-stuff series of symposiums on java: jason hunter, glenn vanderburg, erik hatcher and more!), and friends and contacts from industry whom i've had the pleasure to meet through their affiliation with the austin java users group (jeff zado from quest software). i look forward to running into or otherwise meeting a few more friends at booths, halls, or sessions today.

JSF Session Full..

Java Server Faces was highlighted in one of the keynote demos Monday morning. i had the feeling the technical session on JSF would be crowded. i didn't realize it would be full. is this a testament to the fact that web-based development is still very popular today? i ran into a friend (Keiron McKammon) on my way to hall E134. JavaOne this year feels a little more personal.

So, about JSF.. i think a discussion on JSF is timely, given that very recently a separate web application development framework entered the halls of Jakarta: Tapestry. i'm personally quite fond of Tapestry. it's an excellent framework, and it doesn't build upon JSPs. Tapestry can be considered a competing framework for building web applications in java.

An interesting thing to note is that although sun has developed the java community process as a basis for the java community to collaborate on the development of new standards in the java world, there exist other channels and processes by which terrific and popular frameworks come about. A couple of these are the apache web sites (jakarta etc..) and sourceforge.net.

i think it's fair to say that javaone mostly represents the activities that go on through the jcp, and not so much contributions to the java platform that come from other sources. i think this is a shame. apache projects such as ant are usually discussed in bof sessions at night.

i believe that sun's efforts to rally the java community together are terrific, and a step in the right direction. they've recently published an article on Java User Groups, and pledge more support of JUGs in the future, which is great. another step in the right direction would be to have javaone become a more balanced representation of the people and technologies that make the platform great, and that must include projects, apis and frameworks that are developed through these other channels.

this sometimes does happen. for example, i'm a big fan of castor, an open source data binding framework for java. it's nice to see that both keith visco and arnaud blandin are members of the jaxb expert group and helped define that spec.

likewise, if i'm not mistaken, many of the ideas behind JSF originate with craig mclanahan, creator of the struts web application framework, which is an apache project.

so it's nice to see that collaboration between the sun and open source camps can and does come about.

A late start: Eitan's spiel on java.net

apologies for the late start. imho java.net is a great idea whose time has come. i'm excited to be a part of the java.net effort and to have been invited to blog alongside friends and acquaintances whom i greatly admire.

in a nutshell: java.net reflects the words of tim o'reilly in this morning's keynote speech: it is an effort to bring in the voices and opinions of folks outside of sun. the time has come to unite the various java communities and this is a great way to get started. more on thoughts on this in a followup entry..

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