Lab49 Blog » RIA

FlexUnit4 & Parsley

Anthony McCormick — Mon, 10 May 2010 22:01:47 +0000

For the last six months I have been working on a rather large enterprise application that uses parsley as it’s main Dependency Injection Framework. This has led to many complex class’ that contain multiple injected models, VO and other elements. Recreating these items inside test harness can become very cumbersome if you have to create a large injection heirarchy. Consider the following example.

My Take on ActionScript 3 shortcomings

Administrator — Mon, 22 Feb 2010 15:06:24 +0000

I have been playing with ActionScript 3 lately and I will say upfront that I like it, it does what it’s supposed to do pretty well: Provide a thoughtfully designed language targeted specifically at the Flash platform.
But it has also been touted as an object oriented language with optional compile-type checking and so I had certain expectations when I took the language for a spin, with a eye towards developing large (as in a few thousand classes) application.

Here are my thoughts on what is missing and why I think those features should get implemented as the language matures and tries to appeal to a wider range of developers (think non-”traditional” one who have been working mostly on non rich web application application). By the way, I don’t consider myself a language expert and my opinion may evolve as I write more ActionScript code.

- No support for multi-threading. I feel that this is the most glaring shortcoming. I understand that it can get tricky for any language belonging to the JavaScript family (I guess it’s more appropriate to use ECMA family of languages here, or ECMA-compliant, but ECMA is a weird acronym that just doesn’t round right) to support threads when it’s meant to run within many browsers and on many different operating systems but this could be one of the main reasons why some enterprise projects may shy away from ActionScript 3. But then again AIR is a desktop solution, and still no threading. Maybe Adobe and the community should seriously reconsider this missing feature. haXe could be considered as a model (http://haxe.org/doc/neko/threads?lang=en)

- Limited native types. You just get 5 of them: String, Boolean, Number, int and uint. It may be an indication of the language purely dynamic origins where such considerations were not important. And what’s with the inconsistent use of cases: String and int (upper and lower)? I guess it’s for legacy reasons. You could argue that if you really need to make a distinction between double and float then maybe AS3 is not the right tool just as you could argue that for people who want to use AS3 for the visualization of complex analytics such a distinction does matter. There is a lot of room for debate here.

- No overloading allowed for constructors, methods, or even between a variable and a method. This is a limiting factor in larger OO applications. Overloading constructors, for example, greatly contributes to the usability of your class. On the other hand I do like the mandatory inclusion of the ‘override’ keyword in subclasses, in line with the trend of other languages (or Java’s @Override annotation; for Java it’s too late to enforce it as a keyword)

- No abstract classes, but there are interfaces. Again, that’s a missing piece in the arsenal of an OO language as interfaces are not exactly the same thing.

- Interfaces can only declare methods, not variables or constants. This restriction can be lived with, but why?

- An .as file must have only one externally visible (public or internal) class or function; this a compiler (mxmlc) restriction, not an AS3 restriction per se. This can become annoying for a file defining global utility functions.
It’s worth noting at this point that there are a few ActrionScript compilers out there, a tribute to the vitality of the community, but that’s a little bit off topic in a post titled “AS3 shortcomings”, isn’t it? So I’ll just add that MTASC is great, but specifically geared towards AS2 with no plans for AS3 as they announced that they are focusing on haXe (by the way they are the creators of haXe). I never tried swftools, though I should. Maybe this bullet point will prove invalid.

- No Generics, which gives the language a very pre-Java 5 feel. This is felt even more acutely given the many resemblances to the Java language. They could have been inspired by GJ, the work on STL, etc… For some reasons it has been left out. This may not be necessarily hurtful for people used to work with the AS3 Array class (it’s a heterogeneous collection of objects) but you do feel their absence when you are trying to write a method where arguments can be of a certain type and all of its descendants but no more, i.e. you don’t want to necessarily resort to the * notation.

- Speaking of Array, what’s with the delete operator? It does not really delete (for that you are better off using splice()). Maybe that’s what happens when you try too hard to come up with a unique syntax for your language. At this point I am tempted to say that we should just stick to the C++ syntax, but to each his own and this type of debate can easily degenerate into futility, so let’s leave it that: The ‘delete’ operator does not delete an array element (when used in the context of arrays), it merely sets the element value to undefined, and that’s misleading.

That’s it for now, I will probably post a follow up where I explain why I really like the event dispatching model and some of the language functional features.

Filed under: ActionScript 3, Adobe, RIA Tagged: ActionScript, AS 3, Java, Object Oriented, OO

Morgan Stanley’s Matrix webcast recording

Dhruba Bandopadhyay — Tue, 25 Aug 2009 22:35:36 +0000

A month back a live webcast took place titled ‘Transcending the client experience’ that focused primarily on the use of RIA in financial services and particularly within Morgan Stanley’s Matrix. A recording of the webcast is now available. I offer a small summary of some of the highlights here.

RIA offers a zero footprint in terms of installation effort and supports real time data presentation through simple yet rich user interfaces. It is bringing the business closer to its clients and is more than just technology in that it is solving real world business problems.

The progressive trends are as follows. There is a front-end shift in that applications are now more driven by user experience and design than previously, can represent large amounts of varied and real time data more coherently and concisely and are increasingly beginning to approximate thick clients in that they are stateful and taking on more of the responsibilities of the server side.

Going forward opportunity is seen in adding threading support and mobile device support to Flex and also in migrating the vast amount of legacy applications currently existing to RIA technology. Morgan Stanley’s Matrix received special recognition throughout being one of the largest production Flex applications in the world, if not the largest, at more than six hundred thousand lines of code developed in the timeframe of a year.

[ Recording of the "Transcending the Client Experience webcast", organised by Adobe and Finextra. Participants in this hour and a quarter long session discuss how developers at financial firms use rich Internet application technologies to integrate real-time data, with the delivery of audio, video, reports and rich interactive charts to trading applications.]

[Panel participants: Hishaam Mufti-Bey (Matrix founder and global director at Morgan Stanley), Stephane Malrait (Global Head of eCommerce at Societe Generale), Mark Greenaway (Adobe), Trevor LaFleche (Senior Analyst at Financial Insights). Moderator: Vivake Gupta, Managing Director, Lab49.]

RIA: Matrix WebCast

Matt — Tue, 21 Jul 2009 20:36:12 +0000

Finextra webcast – registration here.

RIA: LCDS Edge Server – STOP THE PRESS

Matt — Fri, 17 Jul 2009 22:25:18 +0000

I take my hat off to Adobe. Adobe’s up and coming release of Adobe LiveCycle Data Services 3 has one impressive feature that I am completely sold on – because I was on one of the many conference calls 1.5 years ago that forced the feature to get accepted and pushed into the LCDS stack – Edge Server functionality. Although the current LCDS 3 beta download unfortunately doesn’t have the appropriate documentation (soon to be fixed), LCDS 3 beta does have the killer feature almost every sell-side institution requires – Edge Server Push.

“The Edge Server is a LiveCycle Data Services server specially configured and deployed in the DMZ”

Security teams should love this feature simply because it talk security all the way to the bank:

“Flex Clients that connect to the Edge Server through open ports in the external firewall have no direct access to a LiveCycle Data Services server in the internal network”

The Edge Server is also cluster aware: “The Edge Server sets up a gateway connection on behalf of a client in a balanced manner across available nodes when clustering is used in the application tier.”

The fact that the sample applications is a sample stock trading application speak volumes for the investment Adobe have made to enable this feature and support the sell-side – the application supports foreign-exchange currency pair trading.

It’s nice to see that the sample application has been thought through from the perspective of using two Edge Servers in the DMZ with a load balancer in front of them that handles HTTP sticky sessions. There are two LiveCycle Data Services application servers in the application tier. For clients connecting through a load balancer that supports HTTP, configure the load balancer to support sticky sessions, pinning all requests from a given client to the same Edge Server.

Questions for Adobe:

When can we get security documentation on the LCDS Edge Server?
Can we get some LCDS Load Test tool results of the Edge Server?

I wait in anticipation of what Microsoft will counter with. But as of today, Microsoft’s only hope is Lightstreamer, Kaazing, Caplin or similar – none of which are based on a .NET stack. It’s taken Microsoft n years to understand CEP, how long will we have to wait until we get COMET push ?

UK Silverlight Launch – 22 July

Matt — Fri, 17 Jul 2009 18:00:17 +0000

Looks like 22nd July is the day for the UK – why are we always behind the US?

Offtopic:

WCF Duplex Bindings With Silverlight
SocketShifter
Sobees – Silverlight 3 Social Network Aggregator
nibbles – sketchy stuff

Silverlight 4 Requested Features

Matt — Fri, 17 Jul 2009 17:55:56 +0000

A brief poll across my colleagues generated the following list. Hopefully Microsoft will deliver

TruncateToFit on TextBlock (as per Flex)
The ImplicitStyleManager in the toolkit is pretty rubbish, especially for itemsControls where it doesn’t apply the theme to newly added items in the itemsSource and is generally a bit flaky and hard to use and understand even when using ApplyMode.Auto and the performance tended to be very poor using around 50% CPU.
ReaderWriterLock or ReaderWriterLockSlim
Lack of markup extensions: x:Type, x:Null, x:Static – Let’s say you have a DependencyProperty of typeof(Type). At the moment the only way to set its value in XAML is by creating a bespoke TypeConverter class. Very painful and introduces many breaks with WPF
XmlnsDefinition – fix the using statement problem in the generation of the .g.cs file
DependencyPropertyKey – Allow creation of readonly properties as per WPF
Programmatic Clipboard support
Custom Drawing on a Control – as in wpf being able to override the OnRender method and draw to the DrawingContext.
Triggers
More binding options (relative source)
Built-in mouse support
Drag drop support
More informative binding error notifications – i like knowing what property is missing on what object but i would like to know which view has the error
More linq stuff (Enumerable extensions, hash set etc)
Some of the TPL primitives
Routed events (properly)
Themes
Commands
OnRender virtual method and DrawingContext etc.
VisualBrush
RoutedEvents don’t work as they do in WPF as far as I can tell, mainly because you don’t have a way to specify that you want to see handled events which is very annoying in certain situations, e.g. Drag drop
LayoutTransform would also be a welcome addition instead of just a renderTransform.
Stop swallowing mouse events.. I don’t care if the event has been handled or not I need catch the MouseLeftButtonDown event at all times through proper event routing. Also stop sealing methods and classes, e.g. Canvas is sealed and MeasureOverride is sealed event though the documentation says “Classes can override this method to define their own measure pass behavior.”

London Event: Introduction to Flex 4

Matt — Fri, 17 Jul 2009 17:55:37 +0000

Introduction to Flex

To kick start what will be a regular meeting for those interested in rich Internet application development using Flex and associated technologies, Andrew Shorten from Adobe will provide an introduction to the Flex 4 SDK and the design and development tools that can be used to build Flex applications.

This practical session will demonstrate the use of MXML, ActionScript, visual components and connecting to HTTP and Web Services to build a simple application and will set the scene for future sessions, which will extend the discussion on Flex into more advanced topics.

There will be plenty of time for Q&A and a discussion on what topics are of interest for future events

Flexing Your .NET 3.5 Skillset

Matt — Fri, 17 Jul 2009 13:52:49 +0000

.NET Developer’s Journal has an article (written Lab49) on Flex.

“Conclusion:As Silverlight and WPF mature and gain mainstream acceptance, Flex and Flash will undoubtedly be forced to evolve in a direction where they can stay competitive. It’s likely that there will be further feature swapping and parallels between the two. If you do find yourself in a position where you or your team will need to work on a Flex application, don’t feel that you will be throwing away what you know and starting from scratch. Rest assured that you will be in the best possible place to pick up the new framework as well as anyone, and can continue to build on the .NET infrastructure and support that you already have”.

Flex has the lead over Silverlight in terms of browser plug-in penetration. In terms of features Silverlight 3 is released but Flex 4 will follow soon, and until the Silverlight 4 release probably have a richer feature set. Further, Microsoft has somewhat of an interesting battle on the RIA server side when comparing RIA Services vs Adobe LCDS.

Adobe Server Coolness – LCDS

Matt — Wed, 15 Jul 2009 20:40:49 +0000

A few features of Adobe LC DS that you may want to consider in the world of RIA development:

Spring Integration – check out Christophe Coenraets blog
Adobe LiveCycle Data Services 3 – see Anil’s blog for an overview of what’s coming in version 3, and why Microsoft has to push hard with RIA Services.
Streaming AMF and HTTP channels – essentially COMET server technology. You definitely want NIO enabled for scalability. Here’s a recent blog with provide more information on channels and endpoints

Obviously with RIA development you need to consider that if the RIA is going to be used externally, the deployment model of the application server must fit into the existing engineering/security models that are in place within an organization – if not, you should be prepared for some rather long and in-depth meetings to persuade department to “see the light”. Likewise, from an external perspective you should be fully versed on how client have their firewall/proxy setup as this can impact streaming and performance.

Robust Reusable Drag Drop Behavior in Silverlight 3

Charlie Robbins — Mon, 13 Jul 2009 23:12:26 +0000

Recently I had an article published on DevX about how to implement a robust and reusable drag drop behavior in Silverlight 2. The implementation relied heavily on attached behaviors, a pattern that I have used frequently in my work with WPF and Silverlight. The Expression team seems to share my positive sentiment around this pattern and have written a library for Silverlight 3 (System.Interactivity) and added tool support for it in Blend 3.

I decided that it was time that I explore how to re-implement my drag drop behavior using System.Interactivity and I found it to be a painless transition that leads to a more elegant solution in my opinion. There were some refactoring patterns that came out of this effort:

Attached properties used to set an attached behavior become dependency properties on the behavior class itself if you want to set them in XAML.
Attached properties used for state management in an attached behavior become properties on the behavior class itself.
All event handlers for attached behaviors no longer have to be static methods.

In addition to those points, I’m curious how one would implement a behavior that multi-targets certain types that may be disjoint in the inheritance hierarchy (i.e. may not have the same base class). An example is a behavior changes the background property of an element. FrameworkElement does not have a background property, but several of its children do (such as Border and Button). One solution I’ve thought of is to target the highest element in the hierarchy and have a dictionary of valid types that you can attempt to cast when the behavior is attached. Seems like wasted effort and doesn’t give the best Blend experience for the designer. Just something to think about I suppose.

The code is posted at GitHub.

Posted by Charlie Robbins

Microsoft Silverlight to take on Flash in the Dealing Room

Matt — Mon, 13 Jul 2009 20:39:31 +0000

Finextra covers the Silverlight 3 launch from the dealing room.