Archive for the ‘programming’ Category

Moving into the .NET world

Brian LeGros | June 15th, 2008 | programming  

With my latest employer, I have taken the big dive into the .NET world. I’ve spent most of my career working with ColdFusion, Java, PHP, Flex and dabbled a little bit in the Ruby/Rails and Groovy/Grails world in addition to the obvious set of web technologies and standards that span all of these application languages. My limited experience with .NET was through some undergraduate and graduate work I did with C# as well as helping (if you can call it that) with an ASP.NET a long time ago with a colleague of mine. I am a application developer; even though I dabble in lots of different areas, the bulk of my knowledge is building applications in a corporate IT environment. I focus on implementing business requirements and managing technical concerns as it relates to the software development process. I’ve had jobs in the past associated with business and management roles but at the core I am a plain and simple application developer. As I’ve been getting my hands dirty in .NET over the last few months I figured I’d share some of my initial impressions. Please keep in mind, I may be looking at a lot of things in a very naive light, so read what I have as my opinion, ignorant or not.

With context out of the way, I have to say that so far working with .NET hasn’t been a negative experience. There is the whole you’re stuck with Windows thing, but since I’m in fully entrenched in the MS world now, I’ve been able to get past it. There have definitely been some nuances to get used to, but nothing extremely difficult to overcome. Here are a few comments on some of the things I’ve run into thus far:

  • Namespaces in C# aren’t constrained by the file system with respect to partitioning your code. Initially this seemed like a nice decoupling, but I’ve found myself forming more of a dependency on tools to navigate my classes hierarchy rather than just looking into a folder.
  • There is no notion of a shared class path as there is in Java. If you want to get a hold of an assembly to use in your application you’ve got to find it and pull it in. I think there is a configuration option on an assembly that you can use to help, but I haven’t had any experience using it.
  • Assemblies are pretty nice build artifacts. Versioning is addressed out of the box and integrated with the .NET framework. I’m not sure how they stack up against something like OSGI, but I’m enjoying having them around.
  • Everyone says the implementation for generics is better in C# than Java, but as an application developer I don’t notice a difference except that I’ve been told I can use reflection on them in C#. C# also seems to have made a much larger use of them in their core over Java. It seems like stronger typing is a very important practice in the C# world than in my experience with the Java world, but that is probably biased based on how I’ve used Java.
  • There appears to be a very balanced view on uses for metadata (attributes) in .NET. Annotations in the Java world were a great addition to the language, but sometimes their use comes off as abuse; look at a JUnit 4 test suite class for a great example.
  • There are lots of accepted libraries available that are direct ports from the Java community such as NUnit, NAnt, Spring.NET, CruiseControl.NET, NDocs, log4net, etc. Getting comfortable with these libraries was pretty easy since I’d had experience with the Java equivalents.
  • The help systems in .NET leave much to be desired and make me long for Javadocs, Livedocs, RDoc, or anything else. I find myself clicking through a class definitions on MSDN and after two or three links I can finally get to a list of “members” that belong to a class, only to click another link to load another page to see more about the details of that “member”. I have yet to find any easily usable API documentation.
  • .NET has a solid component model available out of the box. WCF is a really simple and tight implementation of a component architecture. Service-orientation is a focus with an emphasis on abstracting away protocols, execution environments, and exposing metadata for a more contractual usage. It has the feel of being an API built around WSDL 2 and many of the WS-* standards, but it goes by many of the concepts, although not by name, identified in Patterns of Enterprise Integration. It’s compatible with synchronous and asynchronous operations and did I mention simple to use? I hope to do some posting about it later.
  • Getting used to assimilating applications into the bowels of the OS seems to be core to the .NET mentality. This is probably just a matter of perspective for the developer, but based on the examples I’ve seen thus far, the user folder, the registry, and Windows\system32 folder are popular hang outs for lots of applications. I’ve been met by quite a looks of confusion when I mention deploying applications without the use of some type of installer. There is a lot of power that you get from this tight coupling with the OS I’ve been told. Unlike my previous shops, writing cross-platform applications doesn’t seem to be a priority for .NET developers, so tight coupling it is.
  • It took me listening to the episode of SER with Anders Hejlsberg to understand better it, but it appears to be that developing in .NET is meant to be an IDE integrated experience via Visual Studio. Regardless of the aspect of development I’ve worked with in .NET thus far, the development experience has been fairly consistent. There is always some visual representation of the code available (where applicable) and a debugger is always around and working no matter the context (desktop, web, etc.). At first it was so simple that I felt like I was missing something, but from what I have read and heard, as much work goes into VS as does the .NET framework, if not more. If anyone has used Netbeans for Java web development, it’s a very similar experience in terms of its integration with the environment.
  • I’ve always seen code insight as a supplemental thing, relying on documentation for the majority of my work, but wow, code insight (intellisense) seems to be the major crutch on which a lot of .NET developers place themselves within VS. What’s weird is that I don’t notice anything different than what you’ll experience when working with Eclipse and Java, in fact, the code insight seems to be limited to code only. I have yet to run into a situation where the IDE makes a suggestion on how something could be written or changed as IntelliJ does for Java. I will admit though, maybe I’m missing something.
  • The visual editors in VS seemed to get abused by .NET developers. I say abuse because quite a few .NET developers I’ve encountered can’t talk to me about their code in any other context but how they dragged-and-dropped controls onto a screen and edited properties. Since I don’t know the in’s and out’s of the tools quite yet, having a conversation is tough. I try to communicate in terms of language agnostic principles and patterns but most of the time all I get are blank stares and judgmental comments about how I am over complicating things.
  • MS alternatives exist in terms of the IDE and runtime, but they don’t seem to be popular at all. I really like SharpDevelop as an alternative to Visual Studio. It’s clean, easy to use, and integrates with a lot of OSS packages out of the box. Mono is available as a Linux-based .NET runtime that has a lot of .NET developers excited because of its potential to allow them to code for the Mac. I don’t know any Mac owners that have Mono installed however, so I don’t know if it’s really a viable cross-platform solution.
  • I have some thoughts on ASP.NET web forms that I want to share, but I’ll save that for my next post.
  • The developer community has always been important to me and I feel it’s always important to remain active in the community in some capacity. As I’ve begun attending the local .NET user group meetings, I don’t see a lot of topics that are not MS centric. There is no question that MS drives the releases of the .NET framework, but there have been lots of innovations coming out of the community that deserve attention. It feels like there are only a small minority of developers that actually utilize these contributions locally. I have yet to see any presentations on the various unit testing tools, build tools, ORM, IoC, etc. that have come out of this space. I do envy the direct support that MS has for its user groups, but I wonder if my expectations are too high.

In any case, so far the learning curve with .NET hasn’t been very steep and when I do get to code I feel fairly productive. I should be posting in the next few days on my thoughts about ASP.NET web forms so I’m sure that will get me flamed, but it’s a major part of the puzzle I’m having to work with that I feel needs some attention. Until next time.

Help with Introspection using ActionScript 3

Brian LeGros | April 12th, 2008 | programming  

Ok, I need help. I’ve been able to discover the coolness that is getQualifiedClassName() and getDefinitionByName() and describeType() when it comes to working with introspection/reflection in ActionScript 3. I am stuck however. I want to get a hold of all the class names available in the compiled Flash movie at runtime. I’m writing a library that will look for custom metadata on classes and associate functionality with the classes (or possibly objects) if they are annotated in a specific way. Right now, short of asking for a list of those classes from the developer, I don’t know of a way to build a bootstrap function/class that will introspection into the Flash movie and get me a list of them. I was thinking maybe if I could find a way to programmatically access the manifest file that would work, but again I can’t find a way to do that.

Does anyone know how to do this or am I doomed to introspecting on objects and programmer declared references rather than classes?

UPDATE: I found a feature request in the Flex 3 JIRA database. Basically it’s not in Flex yet, nor is it supported by the Flash movie, but 4 people have voted for the feature thus far. That being said, please vote for this feature so we can get one of the final pieces to reflection built into Flex. BTW - If anyone wants questions answered with regards to Flex, check out the flexcoders mailing list over on Yahoo. Everyone probably knows about it but I’m slow.

Some of my realizations about user groups

Brian LeGros | March 19th, 2008 | programming  

Tonight I headed over to the Space Coast .NET User Group meeting, which consequently meets at my new office. They were trying out a similar 2 topic format, as we do at the Adogo, and it went really well. We started at 6:30 PM and ended around 8:15 PM. This evening they covered Workflow Foundation and its tools in Visual Studio 2008 as well as approaches for working cross team by using shared binary interfaces (also went into dynamic assembly loading a little bit).

What really struck me as interesting at the group was the context for conversation that occurred throughout the night. Everyone was pretty much on the same wave length, or at least appeared to be, and was comfortable; this may have been because of most of them work at the same mega-company or that the group has just been going steady for a long time, however. In any case, it was funny to see that the discussions were very different than what I’ve been exposed to in the past at user groups. There was a baseline of understanding for the work that Microsoft has done with varied technologies and discussions ensued relating to their application, not necessarily what they were and how they worked. This may have a lot to do with the average age and experience in the room (a older“wiser” demographic), but it also could be me looking into things too much.

I think I am finally able to empathize with user group members who have been frustrated with the Adogo recently. I went to the .NET user group looking for exposure beyond what I read daily on the web. The topics interest me, but I want more detail to see if I am getting excited over something that maybe isn’t worth it (and vice versa). I found myself looking for code examples during the presos more since I am new to the syntax, but not the concepts. I was eager to take advantage of the work the speaker brought the group. This was something I hadn’t previously thought about in depth. I always assumed people didn’t want to read the manual and I couldn’t see why the same conviction I had for programming wasn’t present in others. I think I now realize that, as are most things in life, it’s a matter of perspective with respect to what’s important to the developer as it applies to technology. This may seem like common sense, but I’m a pretty big moron. In fact, I look at the Adogo and realize, we’re really in a similar boat as the .NET group. Adobe has laid out the majority of the pieces we find ourselves using and until we have a common understanding of their use, it may be unreasonable to expect conversations like what I witnessed tonight without first establishing a baseline. It definitely seems like the sentiment on the mailing list to say the least.

I’ve got the April meeting next month, so hopefully this insight can help me better understand the service that a user group can perform for the community and what I can do to aid in its success.

Podcast Rundown

Brian LeGros | February 16th, 2008 | programming  

I spend about 3-4 hours a day driving to work and back, so I listen to a lot of podcasts along the way. It’s taken a while to put together a good list, but over the last year or so I’ve been able to build up a pretty reliable set of shows. I think I’ve really been able to grow as a developer by being exposed to so many perspectives. I don’t always agree with or understand the content I listen to, but at the very least my exposure to that content has helped me learn to take more of a balanced perspective in my career. I also like to listen to technology and science podcasts, but that’s more for fun.

Below is a list of what keeps me occupied on my drive; I’ve tried to include the feed for each podcast as well. Some are updated infrequently, but I enjoy them. If you’re a developer and are interested in hearing others approaches to development, I hope this list offers some help.

Programming

Tech, Science, Fun

Looking for an easier way to use Java and Flex?

Brian LeGros | January 20th, 2008 | programming  

Marcel Overkijk has taken advantage of the recent open sourcing of Flex to provide a plug-in for the Grails framework to expose AMF endpoints from your Grails application. The AMF end points are created via a service class in Grails. Grails, being built on Groovy, can very easily utilize any Java code, requires little work to configure, and can bundle a WAR for you with a single command. The plug-in looks really promising as does its road map which looks like it will have tools comparable to some of the other remoting packages available for Flex. This plug-in is built for use with BlazeDS, Adobe’s recent open sourcing of a subset of its LiveCycle Data Services product. Although I haven’t tried it yet (and its not recommended for production use), this is a great option to dumping a bunch of JARs into a shared Flex context or trying to setup your own BlazeDS server. Why not let Grails (and this plug-in) do the work for you? Seems like a much easier deployment option, IMO.

I’m also excited to look at Marcel’s code to see if I can learn anything to help in the implementation of an idea I had a while back regarding a Java factory for Flex to create objects from JSR 223 compatible languages using Java’s new script invocation API.

Thanks for the hard work Marcel! I look forward to messing around with the plug-in.

Proof of Concept : Learning Groovy, Grails, JRuby, and Rails

Brian LeGros | January 20th, 2008 | programming  

A couple months ago a few of us at work thought it would be worth looking into some of the newer programming languages and frameworks that have been receiving a lot of buzz. We were particularly interested in some of the productivity boosts that have been preached as a result of using these solutions. We decided to focus on the creation of a proof-of-concept (PoC) for one of our major web sites (sort of a stripped down CMS solution). The PoC consisted of two implementations, one using Groovy and Grails, and one using Ruby on Rails. On the Ruby side of things, we decided to look into JRuby, rather than the MRI or Rubinus implementations, since the majority of our development efforts rely on the JVM. Based on the success of this process, we are even open to considering these technologies as a possible replacement for ColdFusion and its assortment of frameworks that we currently use in our web tier.

I decided to move forward with Groovy and Grails in the first implementation. Its syntax seemed to be the most like Java which is what I am most comfortable with. I spent about 4 weeks learning the basics needed for Groovy and the Grails framework. From the little I’ve used it, I really like Groovy as a language. Learning Groovy was a cinch. The availability of closures, the use of builders to simplify configuration, and the emulation of formal properties using Groovy Beans are all great features. After seeing the amount of work being put into Groovy Swing integration, I can’t think why anyone would want to write a Swing UI in straight Java again; the syntax was just as simple as MXML without the markup. I am curious if any classpath conflicts would occur between dependencies in Groovy and our own projects, but I didn’t look into this any.

As far as Grails goes, I am really impressed at the work put into combining the technology stack on which the framework is based. The biggest and most notable feature I like is its tight integration with GORM. The use of GORM as the relational mapper truly makes working with the database effortless. Integration with legacy databases is fairly simple if you want to re-use your Hibernate mapping files, or if you want to do the configuration yourself in your domain classes. Because of GORM, you can approach pretty much any web application focusing solely on your object model; our shop follows this practice already as do most Java shops, so this is a big plus. On the templating side of things, I am pleased to see the work put into GSP. One of the main reasons we went with ColdFusion was because of the simplicity it provided over JSP, so GSP is a welcome attempt at change. Another feature I really like about Grails is the ability to create service classes to hook into, and expose, JEE endpoints with the utmost of ease. I didn’t get a chance to play with these, but from what I’ve seen in the plug-in section, it looks like working with JMS, SOAP, JTA, and a few other standards is ridiculously simple. Yet another feature I really enjoyed was the integration with Spring Web Flow. The scoping in Grails seems so natural; flows are very simple to construct and alleviate a lot of the hacking most developers have to put up with in the session scope. Finally, bundling an application into a WAR is provided out of the box so creating a Grails app and dropping it on your favorite JEE server is fairly effortless. From the little I got to work with the Grails framework, you can tell the team’s focus is clearly to improve Java in the web tier and they are on the right track. I know offering Spring integration is definitely a big draw for me since we use it so heavily in most of our initiatives.

Keeping in mind I worked with Grails 1.0 RC1, I did run into some difficulties with the framework. The first and biggest frustration I encountered was when working with domain classes. When I changed a domain class, while the built-in Jetty server was running, the server would attempt to reload the Spring context but just hang. As a result, I would have to take about 30s or so ever time I changed a domain class to bounce the built-in Jetty server. I’m not sure if this has been fixed since I played with it, but this really deterred me from working with Grails. One thing that I got frustrated with was what seems like a limitation in GSP. I wanted to create a view to edit a domain class which had a one-to-many relationship with another class. A pre-selected multi-select list box seemed like the perfect HTML widget to use. I was unable to find a way to automatically have GSP generate this for me. I searched the user forums, but I only found a post that said an implementation wasn’t available at that time. I didn’t search for a JSP library that may help, but maybe this could have been a viable alternative short of writing the code to render the HTML myself.

So after the Groovy and Grails experience, I dove into JRuby and Rails. Being that I scare easily at the sight of anything new, a colleague recommended Dave Thomas’ Rails book to get started; I also had other colleagues as resources to help in times of need. Since I’ve become more familiar with the Ruby syntax I must say there are some language aspects I do like. Mixins available at the language level are a lot handier than I would have thought, especially in the context of Rails. Properties and module level methods were nice to work with as well. I can definitely see where the “enough rope to hang yourself” analogy comes from however; I encountered a lot of variations on how to syntactically accomplish the same task. From a configuration standpoint, I also had to do some work to setup my environment. In the end, I had to pull down JRuby (1.03) and install the rails (1.2.6), activerecord-jdbc-adapter, and warbler gems as well as update my JDBC driver. Since JRuby is just an implementation of the Ruby language, however, I was able to use any Ruby reference, tutorial, or example I could find and had no issues.

As far as Rails goes, I was pleasantly surprised by how easy it was to get started. One of the biggest things I like about the framework is the inclusion of data migrations. You are required to interact with the database at a certain granularity but those interactions are abstracted by writing Ruby code. I’m not necessarily a fan of this granularity, but from a maintenance perspective, this is one of the best solutions I’ve encountered for managing an application’s database. I am also glad to see to see the FormOptionsHelper class. When data binding isn’t sufficient, the FormOptionsHelper class provides a lot of convenience methods to help work with select boxes. Tasks such as pre-populating a multi-select list box were extremely simple using options_from_collection_for_select. Lastly, I really liked the work done to integrate the use of REST into the framework. Working with ActiveResource seems fairly straightforward and doesn’t require as much configuration as I expected; that being said I haven’t worked much with this feature yet.

Based on my limited experience with JRuby and Rails, there were a few things of which I am wary. I haven’t looked into this much, but having two language cores available in JRuby freaks me out a bit. Without guidance or standards, I can definitely see a junior developer using Java implementations when Ruby ones are available forming a strange mixture of code. Another point to watch is the current maturity of the tools to migrate a Rails application to the JEE platform. ActiveRecord JDBC and Warbler are still under active development (although close to 1.0 releases) and it did take quite a bit of investigation to get my PoC working with our existing environment. Additionally, I don’t like ERB as a templating language. This is a personal preference, but it reminds me of PHP which I dislike for its heavy use of scriptlets; I really prefer using tag-based markup for templating. Finally, and probably the biggest thing I don’t like, is Rails’ implementation of ActiveRecord. ActiveRecord is cripplingly associated with the relational model rather than your application’s object model. A simple relationship such as belongs_to doesn’t relate to a composition relationship between a parent and child object, it relates to which tables contains the foreign key in your relational model. I designed my PoC with an object model in mind and had quite a bit of frustration, semantically speaking, trying to migrate that model into the mold for ActiveRecord. I felt like my focus was on the database for the most part and that seemed contrary to the goal of the framework.

Ok, so enough for my probably useless feedback, let me tell you what we decided to do. My personal preference lies with Groovy and Grails. The side of me that needs a solution in the immediate however, led to my choose JRuby on Rails. Let me explain. When I worked with Groovy and Grails, my learning curve wasn’t with the language, but with the framework. I found myself having lots of difficulty accomplishing tasks that I had expected to be fairly effortless. I associate a lot of these difficulties with the current state of the Grails framework. This is not meant to come off with a negative connotation, but with the perspective that Grails is the “new kid on the block” and still needs polish. When I worked with JRuby on Rails, the learning curve was with the language, not the framework. Rails met my expectations regarding the work needed to accomplish my goals (short of the ActiveRecord hoopla). Rails has the current advantage over Grails since it’s had the opportunity to be exposed to its community for 2 major iterations now. Getting an environment configured and working is a one time cost; I don’t count this again JRuby on Rails although it was easier to manage with Groovy and Grails. Additionally, running on JRuby provides us with the minimal level of Java integration that we need to re-use our existing architecture. JRuby 1.1’s focus on performance and very eminent release as well as Eclipse tooling support via RADRails are also an added plus.

So that’s the verdict from my PoC, but its not the end of my opinion. Anyone who has read this far and thinks I’m full of shit, ignore this next paragraph unless you want to flame me. I ultimately believe that Groovy and Grails will win out for the majority of users utilizing Java in the web tier. All of the arguments I have made for JRuby on Rails are based around the availability and maturity of its resources. These are arenas in which Groovy and Grails have just recently entered into competition. Groovy is quickly becoming the alternative for those in the Java community who are looking for a syntax with which they are more comfortable that brings a dynamic flare. Although it may have helped, Grails doesn’t seem to have the influence yet to cause the recent spike in popularity that Groovy has received as compared to what Rails did for Ruby. I think Java interop will also become more of an issue as people begin using languages running on the JVM. From the little I’ve seen, I really like Groovy’s approach, it feels familiar. I also think developers, like myself, are looking for re-use from the Java libraries and frameworks that we’ve relied on and with which we have experience. Grails’ tight integration with Spring, Hibernate, and other JEE standards (defacto or not) will make these approaches even simpler. It seems like since Grails explicitly chose to support the enterprise and Rails is choosing to stay out of it. I think Grails over time will have more to offer than Rails for those looking for new solutions on web that are currently using Java. Please keep in mind I’m not saying that Groovy/Grails isn’t currently ready for the enterprise (despite the FUD going around). As I understand it, many have been successful by using these technologies; I’m just saying I’m going to wait a while and see how others have been successful and learn from their examples.

In the end, I definitely think these new languages and frameworks provide a huge amount of productivity compared to how we are currently building applications for the web at the office. Tooling definitely needs some work on the Eclipse side of things, but Netbeans and IntelliJ are providing some great alternatives in the interim. I’m really looking forward to using JRuby and Rails to create our stripped down CMS application, which has recently received the green light. I’m even more excited about continuing to work with Groovy and Grails as their communities grow (and even pushing for its use in the office). Thank you to LaForge, Rocher, Nutter, Bini, and everyone else who has contributed their time and hard work into making Java on the web productive (and fun). I really see potential in the languages being built for the JVM and can’t wait to see what the future holds.


NOTE: Sorry to Jython, Django, Scala, and Lift for not including you in this PoC. For now I’ve spread my wings enough to be dangerous, and by dangerous I mean screw up enough software to retain job security. ;) I hope to find the time later this year to do some more exploring.

Uses for non-visual Flex components

Brian LeGros | December 13th, 2007 | programming  

Recently, I've been interested in examining the features of non-visual components as it applies to Flex. I don't hear them talked about a lot (at least in the small part of the blog-o-sphere that I read), but I think there are some uses for these types of components that could really catch on in the community. I've tried to put together a sample application to show an example of some of the ideas I'm playing with in my head.

So the big place where I see non-visual components having a use is when attempting to bridge the stateless and stateful portions of a Flex application, mainly in the area of remote services. When I design a web service or remote object to be used by Flex, I typically build it in Java (or ColdFusion) and I design the service such that its methods operate in a stateless fashion. For example, when I call a method on my service, I don't expect previous calls to that method to influence the results of my current call; at least from the perspective of the caller. Additionally, I have the expectation that more information may be required when calling the method since the remote object receiving the call has no context in which to interpret the method call besides the method itself. Now I'm know an argument can be made about whether something truly is stateless or not, but that's not the goal of this post. Let's work with this ad hoc definition of stateless for now.

Flex provides us with a very simple, global means to get a hold of these services: RemoteObject, WebService, HttpService; there are other means by which to connect to remote services, but for now let's take the simple example of stateless RPC-based services. Typically in my Flex applications, I want to emulate a synchronous call from the application to the service (using something that implements IResponder or mapping the result/fault methods manually). Ideally I should have a class abstracting these calls to improve cohesion in the application; frameworks like to use command, delegate, or proxy classes, for example. During the emulation of this synchronous call I usually have my result/fault handler call out to a method on a class to change the state of an object (e.g. - setting values on the ModelLocator in Cairngorm), consequently firing propertyChanged events and/or custom events to update visual components via data binding.

All that being said, there are a couple of things with this approach that I want to address. First, I'm making the assumption that the class which abstracts the interactions with my service should also remain stateless. No where in the creation of the object am I changing its state so that the behaviors associated with the object may have a different context when executed. Second, I'm making the assumption that the behavior of this abstracting class must be separate from the data it uses. Propagating a change in an object's state via events is the back-bone of Flex data-binding. Not only that, but data binding is very simple to use and code, why shouldn't this simplicity be available in the ActionScript class abstracting the call to the remote service?

So that's enough conceptualizing for now, let's look at some example code. Please note the entire working example can be found at this location.

In this example, we have a very simple phone directory application. A SearchView exists which takes input from the user and announces a custom event (SearchEvent) passing that user input as its payload (i.e. - SearchCriteria). This event is handled by the Application class which in turn calls the find() method on an instance of SearchComponent. SearchComponent is a non-visual component which uses data-binding to propagate changes from the stateless world into my stateful Flex application. The code for SearchComoponent can be found below:

  1. package com.brianlegros.nvc_example.component
  2. {
  3.    import flash.xml.XMLDocument;
  4.    import mx.collections.XMLListCollection;
  5.    import mx.collections.ListCollectionView;
  6.    import mx.collections.IList;
  7.    import mx.collections.ArrayCollection;
  8.    import flash.net.URLRequest;
  9.    import flash.net.URLLoader;
  10.    
  11.    import com.brianlegros.nvc_example.vo.Employee;
  12.    import com.brianlegros.nvc_example.vo.SearchCriteria;
  13.    
  14.    public class SearchComponent
  15.    {
  16.       [Bindable]
  17.       public var locations : IList;
  18.      
  19.       [Bindable]
  20.       public var departments : IList;
  21.      
  22.       [Bindable]
  23.       public var employees : IList;
  24.      
  25.       private var data : XML;
  26.      
  27.       public function SearchComponent() : void
  28.       {
  29.          var request : URLRequest = new URLRequest("results.xml");
  30.          var loader : URLLoader = new URLLoader(request);
  31.          loader.addEventListener(Event.COMPLETE, function() : void
  32.             {
  33.                data = XML(loader.data);
  34.                
  35.                locations = findLocations();
  36.      
  37.                departments = findDepartments();
  38.             }
  39.          );
  40.          
  41.          this.employees = new ArrayCollection();
  42.       }
  43.  
  44.       private function findLocations() : ArrayCollection
  45.       {
  46.          var temp : ArrayCollection = new ArrayCollection();
  47.                  
  48.          for each(var item : XML in this.data.employee.location)
  49.          {
  50.             if(!temp.contains(item.toString()))
  51.             {
  52.                temp.addItem(item.toString());
  53.             }
  54.          }
  55.          
  56.          return temp;
  57.       }
  58.      
  59.       private function findDepartments() : ArrayCollection
  60.       {
  61.          var temp : ArrayCollection = new ArrayCollection();
  62.                  
  63.          for each(var item : XML in this.data.employee.department)
  64.          {
  65.             if(!temp.contains(item.toString()))
  66.             {
  67.                temp.addItem(item.toString());
  68.             }
  69.          }
  70.          
  71.          return temp;
  72.       }
  73.      
  74.            
  75.       public function find(criteria : SearchCriteria) : void
  76.       {       
  77.          var temp : ArrayCollection = new ArrayCollection();
  78.                  
  79.          for each(var item : XML in this.data.employee)
  80.          {
  81.             if(criteria.firstName.toUpperCase() == item.firstName.toString().toUpperCase()
  82.             || criteria.lastName.toUpperCase() == item.lastName.toString().toUpperCase()
  83.             || criteria.nickName.toUpperCase() == item.nickName.toString().toUpperCase()
  84.             || criteria.location == item.location
  85.             || criteria.department == item.department)
  86.             {
  87.                var employee : Employee = new Employee();
  88.                employee.firstName = item.firstName.toString();
  89.                employee.lastName = item.lastName.toString();
  90.                employee.nickName = item.nickName.toString();
  91.                employee.location = item.location.toString();
  92.                employee.department = item.department.toString();
  93.                employee.phone = item.phone.toString();
  94.                
  95.                temp.addItem(employee);
  96.             }
  97.          }
  98.          
  99.          this.employees = temp;
  100.       }
  101.    }
  102. }

There a few things to note about this component for the purpose of this example:

  • A method on a remote service/object is not actually being called, I'm using an XML document to simulate that process.
  • I am not actually emulating a synchronous call, I'm allowing the current thread to block on the method call. If I were to emulate the synchronous call, I would suggest using anonymous functions as the result and fault handlers for the remote service/object. The code in this example would be short and not warrant a named method mapping (this is done a lot in JavaScript when registering event handlers).
  • Yes, my coding style kinda sucks, get over it.

Now when the find() method is called it does not return anything, instead it updates the component's internal state via the employees property which then fires a propertyChanged event which is handled by ResultsView to populate a datagrid. Additionally, notice that when the object is constructed it makes a call to fetch location and department information to which controls in the SearchView are bound and updated when construction is complete. These values from these controls are used to filter the search performed by the user.

Going back to the conceptual, there are a few questions that come to mind:

  1. Aren't components supposed to be reusable? - From my POV, it feels like Flex has already done a great job of handling re-use through the RemoteObject, HttpService, and WebService classes. It seems that if re-usability is needed it would be at the service rather than the non-visual component. The non-visual component in my example is literally acting as a perspective for its service, or what potentially could be a group of services. Right now, however, I'm not sure if there are huge performance issues that may result from having multiple component perspectives for a single or series of services. I would assume for RemoteObject it may not be as big as a hit as it would be for a web service. Maybe this would be based on the remoting implementation you choose (i.e. - LCDS, BlazeDS, WebORB, Granite Data Services, etc).
  2. Aren't you just causing side-effects on objects? - In my opinion, it's not doing anything different than what Flex is doing with its visual components. In fact, what I think justifies this particular approach is the fact that you have the ability to notify anyone watching the object when its state has changed; I've always considered side effects as changes in state that I potentially didn't know about as the caller. The Flash movie instance is stateful; why not take advantage of this environment to add state to the classes abstracting our services? I'm building these non-visual components to satisfy the needs of my application, so I will know how they should behave and can to document that formally based on the constructs of the language. Now, if you ask me if this approach should be used for building an API-like interface to a set of remote services, then I would have to say no. The implementer of an API doesn't know how their code will be used in the context of an application, consequently keeping these components as stateless as possible is to the benefit of the API developer; context is limited to the execution of a method call. I think the Twitter API for Flash Developers is a great example of this.
  3. Where do I put all of these non-visual components? - This question I believe involves much more conversation about the implementation of these non-visual components. The example application is extremely simple and does not represent the issue of how to handle event propagation. In the example, all events are being propagated to the Application class and emulating a sort of global event system similar to those that I've seen in Flex frameworks with which I've worked. In fact, this is how easyMVC handles its event registration in the ControllerFactory; a ControllerEvent with a user provided type is registered on the Application and no matter where the event is dispatched, it's told to bubble to the Application to be handled by a mapped method in a custom Controller class. I have to admit that I like this approach much better than Cairngorm and PureMVC's approach of building their own global event system. I know both camps have their own reasoning for why they've done it, but I don't think that what Adobe has provided is worth re-writing. On the other hand, does the hierarchical nature of MXML bind visual component layout and construction too close such that without global event systems we can't be productive as Flex developers? On a side note, data binding in practice isn't always the answer to our problems; how a component can take advantage of these non-visual components and still interact with the components it needs to is a mystery to me. This may come back to the nature of MXML as well.
  4. Do I need a framework if I use this approach? - This is something I'm still trying to figure out. The biggest use of Flex frameworks I've found is a structured approach for making calls to remote services. I feel like frameworks have way too much boiler plate code and if this approach is practical, a good alternative may exist in place of adopting a framework. It seems to me like Flex frameworks have come from the mindset of the web world where stateless HTTP is king. We don't have to use the Front Page Controller pattern to build rich UI's; I think it's time to move on to different interpretations of the MVC pattern. I always find myself asking, did developers in the Java Swing world find themselves turning to a framework or were the constructs of Swing enough to be productive. If people were productive with Swing and it was a widget toolkit for AWT, why can't the same be true for Flex and Flash?

All this being said, this is just my latest idea. As you can tell, I still have a lot of unanswered questions. We are the process of implementing this approach on a much larger scale at work and hoping to solve the questions listed above. I'm always interested in feedback, so please rip this to shreds. I am far from experienced in this arena and am always open to what others have to say despite what some may think.

NOTE: For those who are interested, I began along this line of thinking based of the latest buzz-worthy topics in the programming community. It interested me as to how OSGI implemented their component architecture in Java w/o some language level support (e.g. - formal properties) and why it so popular. I was also intrigued by a proposal put together by Joe Noxel, from the Java Posse, regarding additions to Java for some of the language level elements already present in Flex. Additionally, SOA has come into debate by some of the more experienced professionals in software engineering and SCA (see Apache Tuscany as an example) has been identified as a potentially better alternative. So all this talk, combined with the little amount of component programming I've done with COM+ and .NET, made me wonder. If there is such a huge draw towards component-oriented design is there anything in Flex that we can do to take advantage of these practices? Does having formal properties and support for events as it presents itself in Flex aid developers with the tools necessary to utilize component-oriented design? Is one of those areas specifically the perspective of bridging the gap from the stateful component to the stateless service? Now I know a component has a much richer definition than I'm limiting it to, but this is just the point. To what extent can we, and should we, use components within Flex?

The CMS Saga Continues

Brian LeGros | October 20th, 2007 | programming  

Over the last two weeks I've been researching CMS solutions in the ColdFusion space. We have a pretty large site with a lot of content so a CMS solution seems like the right fit. I tried out FarCry, one of the popular OSS ColdFusion CMS solutions, and didn't have too much luck. I spent another week looking at commercial ColdFusion CMS solutions and came up on products in two categories: products with very expensive licensing but fully capable and products with reasonable licensing but limited capability. On top of that the price points were over $25K for 2 server licenses and 5 users, on average. We currently have our app load-balanced across 12 virtualized servers, so licensing for most of these apps would be ridiculous.

I ended up looking at the Savvy CMS from BeSavvy and my initial impressions were that I really liked what I saw. The UI was incredibly simple and easy to use. The constructs of approvals, a built-in authorization system, and templating were available and very easy to prep for a PoC. Installation was so easy, it was sick. Unfortunately, we ran into a large wall when we had to address separating content from its presentation. For example, we wanted to store information about all our Resorts, but we may want to show it on a page as a list of resort names or on a page highlighting a single resort's details. In the Savvy product, there was no way, short of extending the application itself (which required different licensing or consulting fees for BeSavvy to do the work) to incorporate our content types (i.e. - Resort, Amenity, Destination) and gain the benefits of all the built-in features in the CMS. We did have the ability to make hooks into Savvy that could manage content reuse if we programmed it ourselves. However, I saw this as busting out of the CMS to manage content when that is the CMS' job to manage content. Why should I have to provide these features? On a side note, licensing for the Savvy CMS was extremely reasonable compared to the other solutions I looked into (licensing per URL, not server, and 5 users was $1350 [see their website for latest pricing]).

So being disappointed that Savvy didn't have the capabilities we wanted, I went back to Farcry and gave it another shot. I had a few replies on my previous blog post that helped me move a little further with the PoC. I was able to get rid of the unusable library tool from my forms (had to patch the core using fixes from JIRA); with some thought, I also found a compromise between using the site tree and the custom content scaffolding. Unfortunately, we really needed Oracle to be the database for our FarCry installation and my every attempt to do so with the the 4.x beta has failed. I spent quite a bit of time on the google-groups applying patches and fixes as people had found them, but I still had issues (e.g. - adding content types via the COAPI after the installation). Additionally, finding documentation on how to use Rules in FarCry was another struggle I kept running into. The developers wiki for 4.x didn't have anything I could reference and the 4.x developer's guide I downloaded covered a very small example of using a rule, but not describe how rules work and the options available for working with rules. As a side note, anyone working with FarCry developer documentation is going to run into a lot of Hungarian Notation; it's actually part of their suggested coding standards. This was a huge detractor in terms of readability for me, but that's just my opinion. In any case, I eventually got a rule working, but the process of doing so was pretty tedious. Overall, I felt like I was jumping through quite a few hoops to get the PoC up and running (e.g. - using fixes from JIRA, running edge builds of the software, etc).

To end this story, yesterday I went to lunch with my managers and talked about the last two weeks of effort I had put into exploring CMS products and my work with FarCry and Savvy. In the end, we agreed that the quirky nature of developing in FarCry and the price points of similarly capable, and more usable, commercial CMS solutions warranted more investigation than we could allot in this PoC process. Consequently, we are going to try and kill two birds with one stone. We are evaluating other web-tier languages and frameworks as possible replacements for ColdFusion (I will go into this in another post). Because of the heavy usage of Java in our environment and the great job we've done separating our presentation and application tiers, we are considering JRuby/Rails and Groovy/Grails as possible options. We have a PoC going on for JRuby/Rails currently, but none for Groovy/Grails. Our hopes are to use this project as the Groovy/Grails PoC. Even though its a custom solution, we want to see if the new frameworks available "now-a-days" (Grails in this case) will provide enough productivity such that a custom solution is more easily maintainable until we can devote the time to doing a much better evaluation of CMS solutions. Additionally, if we find that this PoC works out well, we may not choose to go down the CMS path, who knows. In the worse case scenario, this custom solution can benefit from the work done in past development efforts and we devote more time to CMS product analysis when we're ready.

I've got mixed feelings about building a custom solution, it really feels like a CMS is a good fit here, but for the sake of being productive and getting this stop-gap done, I think we made a good decision. I'm actually a little excited about finally getting to build a Grails app for the office. My Groovy/Grails skills are pretty lacking, so this will definitely help me get some great exposure. Here's to diving in.

Does object persistence complicate architectures with existing data models?

Brian LeGros | October 7th, 2007 | programming  

Recently at work we've been using a lot of ORM solutions on the Java side for our service APIs. Our intent is to focus the interaction we have with our DB resources to that of object persistence rather than ad-hoc data access. So technology-wise the transition has involved going from Spring JDBC to things like iBatis and Hibernate.

To take a step back, let me qualify what I consider to be object persistence versus data access. I see data access as the direct use of a data model (e.g. - relation model via an RDBMS, hierarchical model via XML, etc), by an application. Typically I categorize data access code as code that working directly with the data model's query language (e.g. - SQL, XQuery/XPath, etc). Now, it usually benefits me when working in an object-oriented paradigm to find some type of mapping between the data model and the application's object model, which is where I see the desire to migrate to an object persistence paradigm for data access. In fact, I consider object persistence just a subset and abstraction of the term data access I've defined above. For me object persistence implies that data access is distilled into a simple set of conventions and/or configurable options to allows objects from an application's domain to gain basic CRUD (create, read, updated, delete) behaviors. In my mind, a few popular patterns for object persistence come to mind (ActiveRecord and Data Mapper) but I get the impression that what is perceived as a mature object persistence solution is a solution which completely abstracts the means by which to directly interact with the data model.

I don't necessarily think object persistence is a bad solution, in fact, I can see a lot of productivity coming from a reduced set of work when building an integration layer into your application. What I wonder about is the following:

  1. When an object persistence solution should be selected for use with an application.
  2. The amount of productivity gained from using an object persistence solution.
  3. The degree to which an object persistence solution should abstract direct data access.

Let's take the example of an application being developed from scratch without an existing relational model. I think the 3 points from above are easily answered by looking at how popular the Rails framework has become. I think when building an application anew, having an abstraction for the relational model is great approach. As a developer you can focus solely on your object model which, in my opinion, ideally means more time for working on modeling a domain and deciding on your application's architecture versus how its persisted.

Unfortunately, I think a majority of shops that like to apply the "enterprise" buzzword to their software infrastructure, don't have a luxury of building their data models from scratch. Let's take the example of building an application from scratch using an existing relational model. For this example I think there are a few divisions I have to make before forming my analysis:

  1. The relational model was constructed focusing on standards (i.e. - SQL DDL) and over time has become fairly normalized.
  2. The relational model was constructed utilizing vendor specific objects and over time have become fairly normalized.
  3. The relational model was constructed utilizing standards and vendor specific objects and over time has become more disheveled than normalized.

For the first division, I think an object persistence solution is extremely useful. In my opinion, using a solution that implements the Data Mapper pattern will result in productivity because the implication is that the data access being performed isn't that complicated. I also think that abstracting out direct data access may be beneficial so that it motivates the keepers of the relational model to maintain all of the work they've put into normalization moving forward.

For the second division, I think similar assumptions can be made as they were for the first division. From what I can tell it seems like most "mature" object persistence solutions provide you a means by which to work with vendor specific objects (e.g. - stored procedures, custom objects, rules, etc). I think normalization will save the day as long as the vendor objects in the relational model don't contain business logic which hasn't found its way into your application when it should.

This point I feel leads us to the third division; your shit is all mixed up from a relational perspective. I think object persistence can still be considered for use with an application of this type, but the complexity of the application should come into play as well when making the decision. I think a great gauge of whether or not to go the object persistence route is the complexity of your domain. If I find that I've got 2 domain classes with a simple composition relationship, I don't think using an object persistence solution is going to make me productive; heck, the domain may even be overkill. As far as direct data access goes, if normalization isn't there to provide some structure to the relational model, the implication, at least in my company's case, is that vendor objects were used to supplement the benefits you get from normalization. This means that business logic that possibly should be contained in the application is tucked away in a vendor object; short of rewriting that vendor object, you may need to reuse the functionality it provides. Direct data access at this point is the only option from what I can tell (e.g. - you need to use an inline non-deterministic SQL function as criteria for a join clause in a SELECT statement). From what I've seen in iBatis, object persistence with direct data access is definitely a real and usable option.

As one final point, I think utilizing an object persistence solution, especially in this third division, needs to be approached with a lot of caution when dealing with an existing data model. The forces that drove the creation of the existing data model are not the forces that are driving the creation of the application with which you need to integrate. From what I can tell, in the implementations I seen at work, the object persistence API can definitely start to drive, at a minimum, the way the application domain is being constructed. I'm not just talking about semantics, I'm also talking about data encapsulation and relationships. From what I can tell, based on your architectural approach (e.g. - fat models), this can result in a some pretty strange object behaviors emerging. I don't have any good examples, so that pretty much just makes this paragraph bunk, so hack these last few sentences up to an opinion. I would encourage readers, however, to do my work for me; show me some examples where you find this to be true.

Overall, I really like the idea of using object persistence in my applications, if I feel the complexity of the application and the data model being used warrant it. I do think sometimes that ORM tools are overused, but as employed developers I still think it comes back to finding the right set of tools for the job and being productive. If object persistence isn't going to fulfill those requirements, just remember that it's ok to not use one.

NOTE : I read a really good blog post about ActiveRecord and Rails yesterday that motivated me to finish this post. Even though this post isn't about patterns in object persistence, I think it's a great read if you have some time.

PoC with the Farcry CMS

Brian LeGros | September 30th, 2007 | programming  

So recently at work we have been trying to rewrite an application that is pretty content heavy with some sparse functionality and place it into a CMS. Our motivation in going with a CMS over a custom solution was the hope that we could get the most of content reuse and benefit from the experience of domain experts creating CMS software. Ultimately, I wanted to find a solution that we could hand over to our customers, so changes to the content of the application would not longer require developer/designer resources. I think this is the goal of a majority of people who seek out a CMS as a solution.

Since we're still a ColdFusion shop in the web-tier, I naturally thought to check out Farcry CMS. From what I read about Farcry on blogs, the tutorial videos, the developer guide, and the product documentation, I was extremely motivated to do a PoC with it to show management the potential in using a CMS. We decided to try out the Farcry 4.0.8 beta (which it appears will be what goes out as some type of release candidate eventually) with SQL Server 2005 Express Edition since I had issues getting Farcry running with Oracle (even after consulting the Google Groups).

On paper Farcry offered a lot of the features that I felt would make it a good candidate for the PoC. A few of the ones I found vital were:

  • Developer extensibility in the form of custom content types (in our case identifying business entities such as Resorts).
  • Flexible layouts using templates, containers, and rules.
  • Structured draft and approval system for content changes.
  • Built in role-based authorization system
  • Built-in friendly URL's and RSS feed support

In fact, the biggest draw to Farcry for me was the notion of custom content types; these seemed like a great solution for content re-use in the context I wanted.

I spent about 1 week working on the PoC in Farcry and I think I may have set my expectations too high for the product. That being said, let me preface my comments by saying, Farcry is a solution which could have met my initial goals for this PoC, but I chose not to go forward with it due to the struggle I felt I'd encounter by implementing the entire site. The main struggle I saw was due to usability as the framework is extended. Let me first give a description of the content and relationships I needed:

I wanted the ability to group content into three specific areas: Resorts, Destinations, and Amenities. A Resort has a name, address, city, state, zip, country, phone, fax, image info, etc. A Destination is a custom grouping of Resorts (eg - Central Florida) which had a name, description and some image info. An Amenity has a name, description and image info as well, but was associated with potentially many Resorts; a Resort also has multiple Amenities. The prototype of the application had different layouts we needed to create per instance of Resort, Destination, and Amenity (based on the Resort to which it belonged).

On the development side of things, the biggest usability quirk was documentation and the options left to me as a developer when I couldn't find any. As with any OSS project, sometimes documentation is lacking, I can accept that. Farcry does have a bit more documentation than I expected, but it's usually with respect to the same use cases. In building the relationship between Resort and Destination, I had to undergo trial and error to realize how to create the correct form component. For example, I needed to select the Destination to associate with a Resort from a predefined list, rather than typing it out ("ftType" and "type" set to UUID ending up working). Another difficulty came when learning to create custom content types. Custom content types are created by extending the Types or Versions class in your own CFC and adding <cfproperty> tags to the component as metadata which can be introspected by Farcry. The <cfproperty> tag had a set of custom attributes that I couldn't find documentation on, so I tried to explore the parent classes from which I was extending for more information. I hoped to find code that I could use to programmatically configure my custom content type. Unfortunately, the parent types are intended for use within the context of the CMS framework extension, so the custom attributes were the only means of configuring a content type. If documentation isn't going to be readily available, it would have been nice to have alternatives for configuration so that I could use tools like code insight in my IDE to create the classes I need. Additionally, I know the product is still in beta, b