SpringOne 2008 Day 4

Simplifying JavaServerFaces Development with Spring Faces – Jeremy Grelle
I was running quite late, by the time I was in for this session, Jeremy was out of the slides and busy switching between Eclipse code and the demo web-app. He was covering the “Spring centric” JSF integration approach where you use JSF backed by Spring MVC. And you can use Spring WebFlow to control stateful conversations and navigation rules.

I have used Spring WebFlow 1.0 in the distant past and I it certainly looks like the WebFlow 2.0 syntax is much simpler. It is very much a comprehensive DSL for all kinds of things though and I would guess there is a bit of learning curve. I could spot flashes of the upcoming Spring 3.0 EL++ within the on-screen webflow XML samples, e.g. “bookingService.findHotels(searchCriteria)”. Spring WebFlow appears to encourage doing as much as possible declaratively in the config. Jeremy was recommending that for e.g. instead of implementing action listeners in java code (which is nothing but “glue” code) – just do this directly in the flow definition. This is optional of course, and existing action listeners would continue to participate in the JSF life cycle as normal.

There were a couple of hiccups during the demo which Jeremy recovered from, at one point he wondered out loud if the view did not refresh as expected because of JSF quirks – keeping the whole UI component tree in memory etc.

The Spring Faces tags demos were impressive, for e.g. the rich form input validation messages that gracefully degrade. I especially liked the pop-up demo, which must have been Spring / JavaScript / Dojo behind the scenes. If getting pop-up windows to work with stateful flows, JSF and Ajax is made easier by Spring, that is indeed a Good Thing.

Client / Server Application Development using JSON SOA/REST – Kris Zyp
In this session I realized how much I did not know about what’s going on in the world of cutting edge REST / JSON / Ajax / Dojo / Comet etc. And really, aren’t these the buzzwords of the moment!! So I was glad I picked this session although at times I felt that my head would asplode from JavaScript overload. I had to Google a few unfamiliar things during the course of the session and consistently turned up blog posts written by Kris himself, he is evidently at the forefront of getting a lot of this stuff standardized. I include the relevant links below:

  • Service Mapping Description (SMD) – like WSDL for JSON / REST but with far less suck
  • JsonRestStore – Dojo has a “Data Store” concept that standardizes an interface or set of APIs to read, write and even scroll through data. JsonRestStore is a data store implementation that can automatically use a given RESTful JSON service, provided it conforms to some conventions.
  • JSON Referencing – avoids cyclic references by using only id values with a special key to represent referenced objects – and dojo can even lazy load the whole object from the server, think of this as the JavaScript equivalent of Hibernate proxies.
  • JSON Schema – like XML schema but without teh suck
  • Bayeux – like JMS for the web – or asynchronous messages over HTTP
  • REST Channels – like eventing and pub-sub for the web

Spring Cleaning: Tips for Reducing XML in Spring Configuration – Craig Walls
One of the rare sessions at SpringOne coming from an experienced user rather than a Spring committer. The author of “Spring in Action“, Craig has obviously lots of experience with Spring and I did pick up a few tips. I actually attended two of his sessions back to back hoping to be cured of my allergy to annotations :) This first one covered some basics like using attributes instead of <value>, the “p” namespace, bean inheritance, property editors etc – but it appeared to be quite relevant for the audience. For e.g. I was surprised by the show of hands that not many people had seen the transaction proxy factory bean. Looks like everyone is onto namespaces and annotations nowadays.

The before and after effects for simplifying declarative transaction management were quite convincing and even more convincing was the effect of the Acegi to Spring Security makeover. Spring Security has come a long way indeed :) Craig was pretty emphatic that this is the “best security framework around, period”.

Session ended with how AOP becomes simpler using annotations instead of XML and finally a quick look at JavaConfig. One nice tip I got out of the session is that Jasypt could be used to encrypt externalized config properties like the database connection password.

Spring for the Angle-Bracket Averse: Developing Spring Applications with Absolutely No XML – Craig Walls
That was the last session in SpringOne 2008 (for me) and that’s a long title for a session :) Craig started with a quick look at some alternative contenders like Springy – I had never heard of this (but it is dead now) and the Groovy based Bean Builder. Then he dived into a sample application all done in JavaConfig with zero XML. And no, web.xml doesn’t count. Craig spent time in the IDE, making it clear how this way of configuration could appeal to a Java programmer, you get the benefits of IDE navigation, auto-complete, syntax coloring, type safety, OO, etc. Of course, there are a few annotations to remember and lots of @@@@ symbols in your code. But I guess many people would prefer this to angle brackets and this is just configuration anyway. Session ended with Craig strongly recommending that one should just try JavaConfig once, quite likely you will get hooked. The message was clear that people who used to say Spring sucks because of so much XML just can’t complain anymore.

Update: Solomon has blogged an overall “big picture” summary of SpringOne: http://jroller.com/Solomon/entry/spring_one_themes

Update: InfoQ has a summary report on SpringOne: http://www.infoq.com/news/2008/12/springone-2008

SpringOne 2008 Day 3

RESTful Web Applications with Spring 3.0 – Arjen Poutsma
The “highlight” of the presentation was Arjen’s bright green hair, no really. Rumor has it that he lost a bet? The hall was filled to capacity with people sitting on the sidelines. Some of my take-aways:

  • there is no “right way” way to design REST-ful URL-s, some are better than others, subjective. As someone who has used the Flickr API as a reference, that was good for me to hear. REST zealots would argue that the Flickr API is not a good example of “true” RESTful style, whatever that means.
  • but using hierarchical URL-s and avoiding query string parameters or method “verbs” in the URL is recommended
  • one of the ways you can keep things simple is use the HTTP response codes to determine success / failure of an operation
  • use ETags of course, gives you caching advantages, Spring 3.0 can automatically generate the ETag (using an MD5 hash compare)
  • expect “representation” support (just like MVC views) for Atom / RSS, JSON etc. XML marshalling support is already there in Spring Web Services
  • annotation driven URI templates look quite nice and elegant, can’t wait to try these out

Terracotta – Real Apps, Real Frameworks, Real Use Cases – Ari Zilka (CTO & Founder)
Terracotta sounds too good to be true, I keep wondering what is the catch!? Colin Sampaleanu from SpringSource was also on stage for the first few minutes with a quick intro and comments on how SpringSource and Terracotta are working together to do really big scaling for a client in production. A Terracotta PoC would be high on my to do list when I get back to my workplace.

  • they have an oss reference app you can download and try called Examinator on the Spring WebFlow / JPA (Hibernate) stack
  • no need for SAN / NAS etc, commodity hardware with local IDE / SCSI etc will do
  • Terracotta does all kinds of magic with the JVM behind the scenes. Because it works at the JVM level, you hardly have to make any assumptions when you code, for example your objects don’t even need to be Serializable
  • need a cluster wide singleton? no problem
  • lots and lots of optimizations like using only deltas, lazy loading, minimizing disk flushes by consolidating fine-grained operations, use local memory for reads as far as possible etc
  • use sticky sessions in general as far as possible. and if you use Terracotta with sticky sessions, because of the above mentioned optimizations – Terracotta “will fly”
  • I was quite fascinated by Ari’s detailed answer to a question on failover – heartbeating between nodes, nodes hold “elections” to decide who becomes master / passive when new nodes appear or disappear…
  • some stats: client they and SpringSource are working with on can hit 20,000 TPS on 16 DELL blades with 5ms response time. Now they are on the way to hitting 50K TPS with the same infrastructure.
  • demo of the Terracotta admin console was impressive, he ran a JMeter script. The console can even have you drill down to a thread dump on a node you choose
  • made an interesting comment about a client using Terracotta for messaging “across political boundaries”, you can do things you normally expect messaging / JMS to make possible
  • in case native stuff is involved, you would have to have a proper design to keep all the ‘state’ you need within the Java boundary as far as possible. mentioned a case where they could cluster even comet sockets this way

Spring and Java EE 6 – Jürgen Höller
This session was quite useful for me because I have not been really bothered about the evolution of Java EE much (true Spring fan :P) but here was a great summary from someone working hard to keep Spring complementing Java EE as far as possible.

  • Java EE profiles mean that container vendors don’t need to support all the legacy stuff like EJB 2.0 anymore. I can very well see Spring “tc” server being one of the first containers to be certified when the spec goes final ;)
  • Comet support will be in the Servlet 3.0 spec, I didn’t really know that
  • Bean Validation is “long overdue” as per Jürgen, this is nice and DRY, your persistence annotations would drive your form binding validations. How soon can the Spring Javascript team get this to automatically generate Ajaxy Dojo validations – that is what I’m wondering :|
  • Again and again the message is that the upcoming spec overlaps with existing Spring functionality – e.g. JSF 2.0 @ManagedBean, @ManagedProperty is nothing but Spring @Component, @Value
  • Another example, web beans binding annotations are the same thing as Spring @Qualifier
  • Jürgen’s opinion is that the Web Beans spec is changing a lot, making a lot of “sharp turns”. Feels that there is a lack of consensus on some decisions like sub-grouping the many annotations into logical packages. Pretty much delayed.
  • Says that Spring 2.5 provides a lot of Web Beans functionality already and spring 3.0 closes the gap
  • Another comment he made was that the committee has a tough job – there is already a well established component model which is EJB3. And now Web Beans is supposed to do *only* things that EJB cannot do.
  • So is EJB 3.1 going to end up as a great complement to Web Beans? Jürgen doesn’t appear to think so.
  • The fact that a “singleton session bean” is planned in the spec was news to me. You will be able to even annotate methods as single threaded, async etc
  • Whatever specs are final / close would be included in Spring 3.0, for example JPA 2.0 quite likely. But you really can’t predict everything at this point

At the end of the day I caught parts of Adrian Colyer’s keynote. One notable announcement was Spring will support Flex and SpringSource would be partnering with Adobe. Adrian proceeded to do a Grails live-coding demo on stage working with Spring Integration as well, looked like the audience was lapping it all up, I had to leave at this point.

Update: video of the skit by the SpringSource folks before Adrian’s keynote is available here:

http://www.springsource.org/node/845

SpringOne 2008 Day 2

The highlight of the day must surely have been Graeme “Grails” Rocher building a basic Twitter app onstage in 40 min. I missed the fun, chose to go to the “What’s new in Spring 3.0″ session by Juergen Hoeller instead.

I won’t repeat stuff verbatim as the slides would be released sometime, but will just jot down my personal impressions from Juergen’s session:

  • Starts with a revision of Spring 2.5 config using annotations. Pretty clear that they now recommend the annotation way (even @Autowired !) and minimize the XML
  • After yesterdays keynote preview I was wondering if EL for Spring would make sense but it does, I am convinced.
  • For example the Spring EL will simplify cases like injecting primitive values (think of a “cacheSize” to be set conditionally). I have a feeling that stuff I am currently doing using a FactoryBean can be avoided with the EL. I am yet to try JavaConfig though.
  • Spring will ship with a home grown EL processor, apparently inspired by the JSF “Unified” EL. So it uses #{} kind of syntax. But Spring EL will be more powerful, can even do method invocations. I have not been following the EL scene closely but I distinctly recall a certain other framework that has this feature implemented already. Who came up with this idea first? Hmm.
  • The EL support will be tightly integrated with Spring “scopes”. Think conversation, session, application – even exotic things like Spring Batch “step” scope. Sounds elegant.
  • Spring will move to an Ivy based custom build and release system in future. Juergen did not say this explicitly but it sounded like they are ditching Maven becuase they want better control over dependencies metadata etc. Juergen said that they would end up using stuff that was / is being tried out in the current Spring WebFlow build system. I had noticed when I tried one of the recent SWF beta-s or RC-s that the build was based on Ivy. If this is true, Maven guys won’t be pleased ;) Anyone care to comment?
  • REST support looks neat I could tell a lot of folks were impressed. @PathVariable ftw!
  • Juergen promises “conversation scope” is coming that solves the “concurrent windows in same browser” problem. Uh oh, sounds like I have heard that elsewhere as well. Do I smell another flame war on the ServerSide soon? *glee*. The slide says matter-of-factly that this feature is inspired by MyFaces “Orchestra”.
  • Next slide brings up “serializability” of session and conversation objects. Solution is proxies that reobtain references on deserialization. Now where have I seen this before? Hmm ;)
  • Spring “inheritance based” controllers will still exist but be marked as deprecated in 3.0 in favor of the annotations. I will miss you SimpleFormController and friends, you have served me well!!
  • But I won’t miss things like the wonderfully named JUnit 3.X support classes like “AbstractTransactionalDataSourceSpringContextTests”. I see myself using annotations for the Spring JUnit 4 support very soon. As someone that’s not particularly fond of annotations, now that’s saying something.
  • Juergen says that his view of Java EE 6 spec progress is that it is delayed, was supposed to be done by end 2008. Word is that they are shooting for JavaOne. Juergen feels that it likely won’t be done even then (June 2009). Hurray for standards. Yay. But some specs have come a long way e.g. JSF 2.0 and JPA 2.0, they may go into Spring 3.0, rest goes into 3.1, 3.2 etc when available.

After that I attended the LinkedIn case study. Interesting, they did a lot of work to customize finer details of how Spring does DI and life cycle stuff. I was not particularly convinced that they needed to go as far as they did – but the message was effectively conveyed that Spring is so easy to extend and bend around to do stuff that you want. For me personally, I had never ever ventured into creating custom Spring XML namespaces etc. and this session gave me some idea as to how to go about it.

After lunch came Jeremy Grelle’s Spring MVC and Spring JavaScript presentation. I had seen most of the slides already, downloaded from one of his talks elsewhere earlier but I did find the demos interesting. Personally I hate mixing JavaScript in your JSP but have to admit that Spring makes things easier than it would be otherwise, typical Spring. This stuff is for you if you are using JSP especially with Tiles – you can do partial refresh of fragments. But the Tiles config looks a little too complex for my liking. I guess I should blame Tiles, not Spring, heh. Jeremy appears to be great fan of Dojo, plugs the session by Dojo member(s) tomorrow. Spring Javascript is currently a wrapper over Dojo, they plan to add other implementations in the future like jQuery, YUI. Sounds a liitle ambitious to me. Spring JS 3.0 will have JSON support and “deep integration with dojo.data”, not sure what that means.

I attended the Morgan Stanley case study at the end which I felt was a “fair and balanced” look at real-life Spring adoption, even having a few slides on what the dev team perceived as Spring limitations – although most points seemed somewhat contrived. Having attended the LinkedIn session earlier it was good to see MS take a somewhat different approach to some of the stuff LI did. Very interesting to see that their architecture was all about message processing (CXF), no app servers, no Tomcat. Instead they bolt a custom TCP channel onto a Spring context. They invested in a Spring subscription and had very positive things to say about it, training, accessibility of SpringSource team etc. Overall I got some nice insights on how to pitch Spring to prospective clients especially those having a lot of legacy code. Very, very nice to see Morgan Stanley talk about killing their in-house frameworks and consolidate on stuff like Spring JDBC. They damn well got it right. Some of the clients (and pointy haired bosses) I have dealt with in the past (and wanted to knock some sense into) come to mind. Yeah if you are reading this blog, you know who you are!!

Here is my twitter feed if you are interested.

SpringOne 2008 Day 1

Now off to bed after the SpringOne kick-off and keynote. My, the venue is grand. Bag and goodies are nice but apparently no Rod Johnson bobblehead this time ;)

Quote as I remember it from Rod Johnson’s keynote: “No one uses Tomcat because they played golf with someone”. Hah! Take that all ye bloated app server vendors ;)

My personal (irreverent) thoughts from the keynote, just a few things I remember:

  • Theme this year: “Weapons for the War on Java Complexity”. On the swag T-shirt as well.
  • Yep, more stats and proof that Tomcat is the dominant app-server and even the other app-server deployments mostly run Spring apps. Spring world domination complete.
  • A lot on Spring WebFlow, looks that it plays a big role in the overall roadmap. Now did he actually say that he was not completely convinced that Spring WebFlow was simple enough and made complete sense until recently? Hmm. Yes, SWF syntax much simpler in 2.0 compared to 1.0. Rod Johnson stresses that SWF makes sense for guided page navigation, back button problem, opening multiple browser windows at the same time etc. Spring JavaScript
  • Talks about the Big Choice JSF vs non-JSF, compares this to Republicans vs Democrats, jokes about how ServerSide threads on JSF get hijacked by people who assert that JSF sucks. Rod does not say what he *really* feels about JSF. I will buy a beer for anyone who can tell ;)
  • Hardly any XML shown in the slides, mostly annotations. Guess I can’t avoid this stuff any more
  • In fact “admits” that the old Spring MVC was not really the “right way”. The inheritance based controllers will be deprecated in Spring 3.0. What the! Breaking news: Rod Johnson says that concrete inheritance “sucks”.
  • DM server, AMS, Oracle extensions. Lot’s of “SpringSource” stuff.
  • Aha, something new unveiled, SpringSource “tc” – Tomcat with management and enterprise features added
  • I can buy into this more than the OSGi stuff. Rod says that barrier to Tomcat usage in production is the management and enterprise / deployment features. Hmmm, probably. So you take your existing WAR and it should run on this. Not yet clear if this uses the DM server under the hood, think so.
  • Spring 3.0 will introduce REST support and some kind of an Expression Language. EL that you can embed in annotations and stuff huh!? Now that is interesting, reminds me of something I’ve seen elsewhere. Need to catch the first session tomorrow on Spring 3.0 by Juergen.
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