Welcome!

Adobe Flex Authors: Matthew Lobas, PR.com Newswire, Shelly Palmer, Kevin Benedict

Related Topics: Adobe Flex

Adobe Flex: Article

Developing Adobe Flex Rich Internet Applications with Cairngorm Microarchitecture

Using the Cairngorm Store sample application

This series presents an open-source architectural framework to Flex developers called Cairngorm. In this series I explain the thought leadership behind Cairngorm, the design challenges that Adobe feels Cairngorm addresses best, and the projects for which Cairngorm is an appropriate skeleton for development.

Using the Cairngorm Store sample application, this series explains what Adobe Consulting thinks about scoping, estimating, and delivering a Rich Internet Application (RIA) when basing it on Cairngorm from the start. I also explain the various Cairngorm concepts and take a deep dive into the implementation of the Cairngorm Store.

Finally, I demonstrate some of the principal benefits of delivering an RIA based on this established microarchitecture by adding a new feature to the existing Cairngorm Store application from the point of view of a Cairngorm developer. By this stage in the series, you see the benefits for yourself.

Cairngorm isn't the only way to build a Rich Internet Application, of course. However, Adobe Consulting has helped numerous customers and partners succeed in delivering large-scale Flex RIAs by building upon their preexisting Flex application development knowledge using the information contained in this series.

This comprehensive introduction covers the full spectrum of Cairngorm, from understanding the motivation and concepts of Cairngorm to architecting your own applications upon this established and supported microarchitecture.

Instead of delving into code from the outset, the first part offers a context and background for understanding the Cairngorm architecture. I discuss frameworks and clarify the difference between an application framework and an architectural framework. I then explore design patterns and introduce the microarchitecture concept. Finally, I give a brief background on the emergence of Cairngorm: its history and where it is headed - its roadmap.

You will develop a retail commerce application using both Flex and Cairngorm on the client-side tier and a new or existing J2EE infrastructure on the server-side tier.

Clarifying the Definition of Frameworks
In software development, the term framework is one of the most overloaded and overused terms within and between development teams. When developers write large pieces of code that they consider significant enough to consider leveraging on other projects, they tend to supplement the code with this term. Thus there are many types of frameworks: persistence frameworks, transaction frameworks, logging frameworks, aspect-oriented frameworks, animation frameworks, unit-testing frameworks, and the like.

Before I delve into the discussion of the Cairngorm framework, it's important that I explain an important distinction that the Adobe Consulting team shares with customers and partners about frameworks - specifically the distinction between application frameworks and architectural frameworks.

Application Frameworks
Flex is a tremendous example of an application framework. In fact, the forthcoming release of Flex 2.0 actually distinguishes the application framework piece - often called the "app model" within Adobe - in its architecture. The Flex Framework 2.0 provides a rich collection of class libraries that provide highly granular functionality that developers can use to create custom code. For instance, the Flex 2.0 Collections API provides application developers with all the base-level functionality needed to create managed data collections. Application developers then compose these collections together into higher-level objects that are relevant to their particular application. Furthermore, application frameworks such as Flex typically expose application-level services such as history management, layout management, cursor management, exception handling, internationalization, logging, and so forth.

When a framework provides highly granular class libraries that give a high degree of flexibility to application developers, or when a framework provides application-level services that are useful across multiple developer projects, I call it an "application framework."

Another excellent example of an application framework is the FAST framework that Adobe Consulting has used with customers and partners with great success. The FAST framework, as John Bennett explains in his article, Faster Development with the Flex Application Starter Toolkit (FAST), provides application services for logging and tracing, and value-add class libraries that extend the Flex Framework's own implementation of RPC data services in Flex 1.x.

Architectural Frameworks
Architectural frameworks are different beasts entirely. Typically the job of an architectural framework is not to provide any additional services to application developers except an infrastructure around which an application can hang - to provide the skeleton or internal structure of moving parts, around which the flesh and muscle particular to a business domain can be layered.

In other words, an architectural framework provides a generic starting point for the technical architecture of your application.

Applying Design Patterns
It is hard to talk about technical architecture without paying attention to an important movement in software engineering called design patterns.

Without going into detail about software design patterns, let me just say that the expression "there is nothing new under the sun" is never more true than in the discipline of software engineering. Developers often find themselves addressing engineering problems that appear with regular consistency in application development. Almost as consistent as their appearance is the repetition of solutions for these problems. Wherever such recurrences occur, you can identify the solution as a "pattern," indicated by facing the design challenge and finding the appropriate design solution.

The Lure of Design Patterns
Now a warning: When software engineers first encounter design patterns, the realization of a catalog of solutions to their engineering problems can be a powerful one. Often developers recognize a subset of problems they have encountered and then seek to understand other design patterns and where they might apply them. However, the old adage "when all you have is a hammer, everything looks like a nail" can apply here. You can often find "pattern overload" in an application, where developers abdicate responsibility for classes and collaborations and, instead, shoehorn everything into a Factory, Flyweight, Observer, or Decorator.

Used appropriately, however, design patterns can be a powerful tool in a developer's toolbox. Design patterns not only offer common solutions to problems, but the way developers apply them to an application indicates the intention of the implementation. For instance, whenever you see a Singleton in a code base, you understand that this is a class for which there should be only one instance. Likewise, whenever you come across a Factory, you recognize that there are a number of different objects that a manufacturing class can construct.

Rising through the technical architecture - from the ground-zero of detailed implementation towards the helicopter view of high-level system design - you can begin to appreciate the design in other, recurring ways. Like the Mandelbrot, you begin to recognize higher order structure as your lower level structure collaborates. Thus design patterns begin to coalesce in repeatable ways, offering higher level solutions to higher level design problems.

Microarchitecture as a Composition of Design Patterns
Although a design pattern might have offered a specific solution to a specific problem (in this case, using the Singleton pattern for the problem of ensuring that only one instance of a class ever exists), when a collection of patterns regularly collaborate with one other, their assembly is for the greater good of a greater aim: "How do I intercept user gestures and ensure that a worker class assumes responsibility?" or "How do I centralize the business logic that might be used in more than one context on the client, even though it is actually implemented as a collection of service calls to a number of different types of services on a collection of servers?"

When you start to assemble collections of design patterns into these higher order but nonetheless highly generic systems, you communicate these as "microarchitectures."

Let's take this high-level discussion of application frameworks, architectural frameworks, design patterns, and microarchitectures and put it into context. When Adobe Consulting speaks about the Cairngorm framework, we are speaking about an architectural framework - a starting point for technical architecture that is generic enough to apply in most cases to medium-to-complex Flex RIAs.

Furthermore, when we speak about the Cairngorm framework, we do not mean some monolithic architecture that limits your freedom as a developer to solve problems. Rather, when we advocate the Cairngorm framework, we mean the following:

  • A lightweight framework that offers a little prescription for some of the challenges consistent with the Flex RIAs we have encountered
  • Using a small number of relevant design patterns, where the moving whole is ever so slightly greater than the sum of its static parts
  • A microarchitecture for RIA development - a starting point for your technical architecture that solves the problems as they have been solved successfully before
If we can see further, it is because we are standing on the shoulders of giants.

A Short History of Cairngorm
iteration::two, a software consultancy that Alistair McLeod and I cofounded, recognized that many of the design challenges faced and successfully solved in the world of J2EE application development were still relevant issues in the world of RIA development. We came to this realization back in the days of RIA development with Flash, Flash Remoting, and J2EE - a period of RIA history that we'll look back upon with the same fondness and nostalgia as a C++ programmer has for 6809 assembly language.

Borrowing a subset of a collection of design patterns advocated by Sun Microsystems as the Core J2EE Pattern Catalog, we first presented these patterns to the Flash community in our book, Reality J2EE: Architecting for Macromedia Flash MX (Pearson Education, 2003). To accompany the release of Flash MX 2004, we presented the patterns in a chapter called "ActionScript 2.0 Design Patterns for RIA Development" in Macromedia Flash MX 2004 ActionScript 2.0 Dictionary (Macromedia Press, 2003).

As the RIA technology platform matured from the design-centric approach of Flash towards the declarative programming model of Flex, most of the motives for applying these patterns remained. However, the Flex programming model offered us ever more elegant ways to implement these patterns. Furthermore, some patterns that we considered hugely valuable to Flash RIA developers (such as the ViewHelper pattern) became less relevant in the Flex RIA world, allowing us instead to advocate new Flex-specific patterns of our own, such as the ModelLocator pattern.

At MAX 2004 we announced our decision to release the Cairngorm framework as an open-source project for Flex; a decision that has led very much to its widespread adoption within the community.


More Stories By Steven Webster

Steven Webster is the practice director for Rich Internet Applications at Adobe. Previously, he was the technical director at iteration::two, a world-leading Rich Internet Application consultancy based in Edinburgh, Scotland. Webster is the author of Reality J2EE: Architecting for Flash MX and coauthored ActionScript 2.0 Design Patterns for Rich Internet Applications (ActionScript 2.0 Dictionary) and Developing Rich Clients with Macromedia Flex with Alistair McLeod. Steven speaks regularly at conferences and user group meetings on technical and business aspects of RIAs. Steven is the core contributor to the open-source Cairngorm project, a microarchitecture for RIAs based on J2EE patterns which was innovated by iteration::two over a number of Flash and Flex RIA developments.

Comments (2)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


IoT & Smart Cities Stories
Nicolas Fierro is CEO of MIMIR Blockchain Solutions. He is a programmer, technologist, and operations dev who has worked with Ethereum and blockchain since 2014. His knowledge in blockchain dates to when he performed dev ops services to the Ethereum Foundation as one the privileged few developers to work with the original core team in Switzerland.
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...
Bill Schmarzo, author of "Big Data: Understanding How Data Powers Big Business" and "Big Data MBA: Driving Business Strategies with Data Science," is responsible for setting the strategy and defining the Big Data service offerings and capabilities for EMC Global Services Big Data Practice. As the CTO for the Big Data Practice, he is responsible for working with organizations to help them identify where and how to start their big data journeys. He's written several white papers, is an avid blogge...
René Bostic is the Technical VP of the IBM Cloud Unit in North America. Enjoying her career with IBM during the modern millennial technological era, she is an expert in cloud computing, DevOps and emerging cloud technologies such as Blockchain. Her strengths and core competencies include a proven record of accomplishments in consensus building at all levels to assess, plan, and implement enterprise and cloud computing solutions. René is a member of the Society of Women Engineers (SWE) and a m...
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
Whenever a new technology hits the high points of hype, everyone starts talking about it like it will solve all their business problems. Blockchain is one of those technologies. According to Gartner's latest report on the hype cycle of emerging technologies, blockchain has just passed the peak of their hype cycle curve. If you read the news articles about it, one would think it has taken over the technology world. No disruptive technology is without its challenges and potential impediments t...
If a machine can invent, does this mean the end of the patent system as we know it? The patent system, both in the US and Europe, allows companies to protect their inventions and helps foster innovation. However, Artificial Intelligence (AI) could be set to disrupt the patent system as we know it. This talk will examine how AI may change the patent landscape in the years to come. Furthermore, ways in which companies can best protect their AI related inventions will be examined from both a US and...
Bill Schmarzo, Tech Chair of "Big Data | Analytics" of upcoming CloudEXPO | DXWorldEXPO New York (November 12-13, 2018, New York City) today announced the outline and schedule of the track. "The track has been designed in experience/degree order," said Schmarzo. "So, that folks who attend the entire track can leave the conference with some of the skills necessary to get their work done when they get back to their offices. It actually ties back to some work that I'm doing at the University of San...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things'). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing. IoT is not about the devices, its about the data consumed and generated. The devices are tools, mechanisms, conduits. This paper discusses the considerations when dealing with the...