Maven 2 quirks and the "bandwagon"

I recently found myself developing (and using) a lot of small tag libraries to make my life easier when it comes to developing my web applications. The only thing that really gets me is that when I write these tag libraries, I have to manually update all of the TLD (tag library descriptor) files that are necessary for using the tags in JSPs. This irks me and it occurs to me that there's no reason I can't have Maven generate the TLDs for me based on annotations I place on the tag classes. The only problem with this is that no such plugin exists, so I figured that as a foray into Maven plugin development, I'd try making such a plugin as my first try. It is then that I ran across a rather large and bothersome quirk with Maven : it's not entirely ready for Java 5 and up. In fact, rather than using proper Java 5 annotations, it uses XDoclet comment annotations to provide metadata for building plugins, but that's not the quirk. The real quirk is that it can't handle having Java 5 annotations in the same project as the plugin. It can handle Java 5 enums just fine, but not annotations, which seems rather strange to me.

This is all part of the bigger problem of companies not keeping themselves up to date with the latest Java technology and staying with Java 1.4.2 and earlier. Sun has done a great job of maintaining backward compatibility, and there's (almost) no reason that companies shouldn't be upgrading the JVMs on their servers to the latest and greatest versions. The only real reason I can think of is that somewhere in their code, they've used variables named 'enum' which becomes a Java keyword in Java 5 and up (aka Java 1.5, 1.6, etc), and this can be mitigated by refactoring the code. Hell, Eclipse makes that job quick and easy, especially when you really know your keyboard shortcuts. I'm fortunate enough to be able to use Java 6 (and very quickly upgrade to Java 7 as soon as it's released and stable). As much as this is going to make me a snob, I'm getting really tired of being dragged down by other people's need for backward compatibility (and hence also tool developers' appeasement of these people which then affects me). Seriously people, get your act together.

Java enums are even cooler than I ever knew !

A quick note on Java enums : I discovered today that not only can enums have methods (which is exceedingly useful to begin with), but that you can individually override methods on a per-enum-value basis! That's so cool. I read it on this blog.

An interesting Spring Framework quirk

Recently, I discovered the joy of the PropertyEditorRegistrar interface in the Springframework, for conveniently registering property editors to bind between objects and text when rendering forms. This joy led me to discover an interesting quirk : if you subclass a Form Controller and register property editors that way, the object of a field will be bound to the BindStatus.value property, but if you use a PropertyEditorRegistrar, that value gets edited and the spring representation of it bound to BindStatus.value. This is a small distinction that makes a huge difference when writing (and rendering) your pages.

RSS and Me

I love RSS, I think it's a great way to read the news and generally stay up to date on any sites you read and any (legit) torrents you may want to download, or podcasts if that's your thing. I've been kicking around the idea of having an RSS notifier for our system at work, so that I wouldn't have to be sending out extraneous emails all over the place. According to this guy, creating an RSS feed is stupid simple. Maybe when I get the chance I'll give it a try.

*EDIT* : Ok, me being me, I was fascinated with the idea of dealing with something new and couldn't let it go. I followed one breadcrumb after another and found, fortunately for me, that Spring already has an (Abstract)RSS view class in the Spring Modules library that uses the Java Rome RSS library in the background. I can't wait to slog through the crap I have to deal with at the moment so that I can fool around with RSS and have RSS feeds supplying the notifications for our production system. This is going to save so many headaches.

*EDIT 2* : Heh, this guy's page is awesome. It shows that you can use security with RSS feeds, which will be perfect for my company.

Moar Hibernate !!!

Yet again, I'm posting because of fucking hibernate. One of the old quirks I had run across was that if you had a setter for a collection, ie :

public void setItems(List items)
{
this.items = items;
}

...this would replace the hibernate-backed collection that already existed (if one did) and could replace it with a non-hibernate implementation such as java.util.Vector, and any cached items would not get properly dealt with, and the collection would not get properly persisted, even to the point of throwing an exception. This resulted in me having to change my setters to this :

public void setItems(List items)
{
if(this.items == null)
{
this.items = items;
} else
{
this.items.clear();
this.items.addAll(items);
}
}

The only problem with this is that depending on the scenario, hibernate gets the collection, and then sets exactly the same list object back into the persistent entity we're dealing with, which would result in clearing exactly the same list we're trying to assign. The remedy :

public void setItems(List items)
{
if(this.items == null)
{
this.items = items;
} else if(this.items != items) //fix: identity check the two lists!
{
this.items.clear();
this.items.addAll(items);
}
}

That really should have been there anyway, but hibernate inspired it. Fuck you hibernate.

Spring and PropertyEditors, important details

As mentioned in the documentation, the Spring Framework uses property editors in two places:
1) When parsing ApplicationContexts from XML configuration files
2) When binding beans from HTTP requests.

It's all well and good if the only classes you need to bind are already covered by the editors built in with the Spring Framework, but if you need property editors for other kinds of classes, here's how to get Spring to include them, for both situations :
1) Use a CustomEditorConfigurer like so :

<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
<property name="customEditors">
<map>
<entry key="java.text.DateFormat">
<bean class="com.mypackage.CustomDateFormatEditor"/>
</entry>
<entry key="java.util.TimeZone">
<bean class="com.mypackage.TimeZoneEditor"/>
</entry>
<entry key="java.text.MessageFormat">
<bean class="com.mypackage.CustomMessageFormatEditor"/>
</entry>
<entry key="java.text.NumberFormat">
<bean class="com.mypackage.CustomNumberFormatEditor"/>
</entry>
</map>
</property>
</bean>

* Note * : The editors can be singletons because they're going to be the only instances needed by the application context to parse string values.

2) Implement and instantiate (or otherwise use) an implementation of PropertyEditorRegistrar. This will be used with your form controllers to register property editors for individual fields or whole types.

Ubuntu Linux is finally in the right place

I love Linux. Now, at this point, you're probably thinking that I'm just one of these fanboy nerds that loves to sit on a computer all day and hack on code. You're partially right : I do love to sit on computers and hack on code, but certainly not all day and certainly not at the expense of other fun activities like going to hockey games and being with friends. That said, I like Linux because it's good for doing development and it's ridiculously stable. It's even quite performant as well, which is
quite nice. I like it to the point that I'd want to put it on all of the computers here in the office, and as per the title of this post, I think that Ubuntu Linux is at the point where that's a practical possibility. In the past few days, I've installed Ubuntu 7.04 (Feisty Fawn) on two machines here in the office, set them up to do networked printing, networked file sharing, and everything else that may be needed by office workers. Hell, they can even use the built in Terminal Services client to remote into our server here in the office if they need to do any centralized work. They even have all their networked drives mounted for them, and they can see the Windows domain on which this place runs. The only thing remaining is for the systems to pass the Boss Test : sit the big boss of the company down on one, and if he can print his stuff, access his stuff and access our server exactly the same as he could in Windows, then it stays.

There's a great tutorial on setting up Samba with Windows Shares in Ubuntu here. Printing was
ridiculously easy to set up : I went to System -> Administration -> Printing , it autodetected the printers on our LAN and setting them up was merely a matter of following on screen directions.

MySQL character sets, the end

Many times in the past I've tried to get our foreign MySQL server to properly store and handle unicode character sets. Despite the fact that I repeatedly set 'default-character-set=utf8' all over the config files and set the server and client character sets and collations in my.cnf, it still wouldn't handle them properly. Here's the kicker : to make absolutely sure that the server uses only server settings for handling character set (and sets 'fuck you' to whatever the client requests), you have to use the '--skip-character-set-client-handshake' argument when starting the MySQL daemon (server). This is what finally got it going for me. I hope this post helps somebody out someday. (Given my rate of forgetting things, it's likely to be me)

<rage>MOAR HIBERNATE! :@</rage>

God damn, I'm getting so fucking tired of Hibernate and its quirks. Here's a new one regarding Criteria queries :

When you create a criteria query, you almost invariably have to specify a result transformer of Criterion.DISTINCT_ROOT_ENTITY (that's a quirk, but not the topic of this post). When you have an entity on which you want to build a criteria query and you want to limit the number of search results (ie distinct root entities), things get really tricky. Specifying 'setMaxResults' on the query affects the number of rows returned from the database that are actually inspected. Therefore, if there are any joins on your entity that have collections, this will cause a fetch with an outer join strategy to generate an excessive number of rows and affect the results when using a maxResults setting. In the case of using embedded properties, specifying a fetch mode of SELECT will not override these (this is a glitch in hibernate). You'll have to specify the fetch mode manually in the metadata (be it XML or Annotations) permanently for the embedded class. I fucking hate Hibernate sometimes, I really do.

Spring AOP rage ...subsiding

Spring AOP is breaking my heart. Spring overall is a great framework and I love working with it. The idea of using aspects to interweave code and keep concerns separated and code clean is a wonderful though to somebody who loves to architect software, such as myself. But I swear, it feels like I'm hitting every bug in the book when it comes to using AOP in Spring. Certain pointcuts don't get matched properly, regexp based pointcuts get loaded when they shouldn't, the list goes on. I really want to use AOP to design the next big phase of my project that's coming up, but they're making it really hard to justify the decision to do so. You're making my heart cry, Spring.

Google Disappointment

...do it. You just might find a page with me ... pointing at Google on my screen.

Today I was messing around with some of the CSS styling in my API documentation for one of our company's merchant partners, and I found that some of the elements weren't quite right. I then remembered an article I had read on Digg regarding CSS reset stylesheets, and how Google and Yahoo both use them in their free APIs to provide consistent styling results across browsers, so I went to investigate using one of said reset stylesheets to help me out. I figured I'd Google it first (no pun intended), and upon not finding anything relevant quickly, figured Google would be smart enough to use their own reset stylesheets in their own pages. I pulled up the source on one of my query pages, only to discover a developer's horror : inline styling all over the place, and google didn't even use their own stylesheets anywhere in their main site! The code was horrible spaghetti. I ran the page through the W3C web site validator, and it didn't pass a single standard, ie HTML 4.01 / XHTML (any flavour). As one of the big Web 2.0 sites, I would have expected you to have higher regard for international web standards. I'm very disappointed in you Google.

A quick note on versioning

I've come to really admire the way the open source community has been versioning their products over the last couple years, especially in the java open source community, which I've found to be very bright and vibrant. Generally, the projects adhere to the following conventions (where 'x' is an integer) :

Version :
x.x.x - Version with major version, minor version, patch increment
0.x.x - Beta software, not to be considered ready for production use (generally, some projects have very odd development cycles and version conventions)
1.x.x - Version 1 (good for looking at, but you may want to wait for version 2, especially Apache projects *cough*maven*cough*struts*cough*)
x.x.x-Mx - Milestone beta version - has certain promised features according to the milestone version, but not the final version with that number
x.x.x-RCx - Release candidate beta version - has all the promised features according to the release plan for that version for the project, but is not considered to have been sufficiently tested

If anybody feels differently about my descriptions, please, by all means, correct me.

Weak Java

I rarely (if ever) use switch statements, mainly because if their use is required, generally a very poor design decision has been made. But sometimes they're the right choice. That said, I was forced to use a switch statement in some of my code today, and found that Java switch statements can only switch primitive ints and enums in the java language. Not even longs or shorts. That is the weakest shit I've ever encountered. Are you fucking retarded Sun ?

Sorry, I just had to bitch about it, because it's just that stupid.

I love Eclipse now more than ever

Eclipse has always been a very useful platform, with tons of little developer driven quirks that make the programmer's job so muche easier. I found this out especially lately when I've been trying to get into developing with C# in Visual Studio 2005, and I've been missing features that are just there in Eclipse, but you have to buy a plugin for with VS2k5. And here's the great thing about that whole situation : you can develop C# in Eclipse on Windows with a free plugin. But that's really all just a side note. The main point of this post is this : I just now observed an exceedingly useful feature that's been in Eclipse for several versions. Ever press Ctrl + Shift + T to open the quick loader for classes ? It has a text bar at the top so you can type in the simple name of the class you're looking for and it'll filter out the results. In the filtering options up top, there's the usual ? and * filters, but beside that there's also a spot that says "TZ - TimeZone" which I've never really noticed before, and I don't know what made me notice it today. I typed in TZ, and much to my surprise, a whole list of classes remained in the window, filtered, and they all had TZ capital letters in them, following the general naming conventions in Java. Intrigued by this, I typed in MPREF (ManualPaymentRequestEntryFlow) which is a class in my project that I just finished working on, and sure enough, it filtered the list to have that in it (it was the only class not filtered out) . I thought that was just the greatest filter I'd ever seen. And to build on it, if you use the content assist hotkey (Ctrl + Space) with the same scheme, it automatically fills in those classes for you. How cool is that !?

Moar (sic) hibernate !

Yet more hibernate fun facts that I wish I'd had before I started any projects : Hibernate has the ability to persist instances of java.util.Locale, java.util.Currency, and java.util.TimeZone. A sprinkling of a few bits of these pieces of code and their corresponding hibernate annotations could have saved me an assload of time spent on doing my own design, development and testing.

On a small side note, I found I've actually managed to come up with a much better and more appropriate solution for dealing with currencies than the java.util.Currency class, as it's woefully inadequate to the task of dealing with currencies in an enterprise system. I refer specifically to the way it deals with floating point arithmetic in its number of decimal places, rather than adering more closely to the ISO 4217 specification whereby currencies should have a base and an exponent when calculating a multiplier to go between base currency units and major currency units.

Rampaging bull software design

If you're into the software scene, then you most likely know that some of the big buzz terms in the last few years have been RAD (Rapid Application Development) and Agile development (keeping your code clean and maintainable, and incrementing your design and development process in very small steps). With ever changing requirements and very little chance to get the big picture ahead of time given the small amounts of information I get from my bosses, I have no choice but to follow an agile development process. As best as I can tell, I've been doing so ever since I've started here.

Unfortunately, this style of development has caught up with me : I'm finding that even though my code is fairly clean and very easily maintainable, there are memory leaks (I'm using Java, so this means that something's holding onto references and preventing the automatic garbage collector from doing its job). This means that I now get to go back with a profiler, analyze the running of my software, and find out where the leaks are and correct them.

This is going to be interesting.

Moar (sic) Spring Batch !

I received a pleasant surprise in my inbox today (which doesn't happen often), and that surprise was an email from the Spring Batch team notifying me that they'd just released Spring Batch 1.0-M2 to the subversion repo and made it public. This was great because it gave me a chance to download the code and play around with it, look at the samples, and generally get an idea of what's coming for Spring Batch.

In case you weren't aware, I've been looking forward to the release of Spring Batch for quite a while because it can help me a great deal at work, where I'm already using the Spring Framework for my web applications. Unfortunately, the M2 release doesn't appear nearly ready for a production environment, but it's a start. I want more ! faster ! now !

Why you should write good software

Today at the company where I work, our remotely hosted server went down suddenly. Nobody know why, and then the shit started to hit the fan, with emails flying back and forth, and phones ringing off the hook in search of an answer to that one timeless question, WTF ? Of course, everything filtered towards me eventually because I'm considered responsible for the server (even though I'm no where near it and if I don't have a network connection to it, I can't do shit). After several phone calls back and forth between our former partners (who happen to be in the same building as our ISP and still maintain our server), and our ISP, and our firewall technician (who, oddly, is outsourced by our ISP and doesn't technically work for them), it was discovered that the machine was alive, but not responding to any network traffic, so the quickest and simplest solution was to just get somebody to reboot the machine. Eventually, one of our former partners' employees went down to the cage and rebooted the server. Later, in an email explaining what had happened, that same employee (who happened to be their sysadmin) explained that their DVD backup had frozen the whole box and that this situation had never happened before. (This during our peak period for the day).

Now, I can believe that (I've had weird shit like that happen to me, so I can't really bitch at the guy.) But it brings to mind the need for good software and why good software should be written : if you write software, and it fucks up, then the managers of those using your software don't see it as your fuckup, they see it as their employees' fuckup, and hold them responsible. I hate the thought of being one of those employees (and very nearly was one today). This has brought forth some small amount of Karmic inspiration to put more time into testing and finding those odd failure modes for my own software that you wouldn't think can happen, but can because you eventually hit an odd and unexpected set of circumstances. Just something to think about if you're a serious developer and you're reading this.

Linux : the more you know ...

I'm somewhat embarrassed to admit this, but I've just discovered Linux ACLs, which are apparently in every kernel 2.6+, and has plugins for 2.4-. I guess a really linux savvy person should know these, especially since they're incredibly useful and give so so much more power over the default User - Group - World permissions built into the file system.

JSP Tags

They're oh so useful for encapsulating small bits of reusable logic, but, here's the kicker : when they're compiled, only one instance of a tag is generated for a given page, so you have to design them to be stateful and ensure that you override the 'release' method when inheriting from TagSupport or BodyTagSupport. It took me a couple of hours to figure this out, and sadly, it was for the second time. I guarantee there won't be a third after this.