Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion

ColdFusion: Article

Mach-II

Mach-II

With the release of the MX version, ColdFusion has moved from its strict procedural programming background toward object-oriented design and programming. This move has evoked both hope and fear in developers, some welcoming the decidedly new concepts of object orientation (OO) and some dreading that they will lose the language they love.

Within the Fusebox community, the introduction of ColdFusion components (CFCs) has stirred a great deal of interest: Would Fusebox leverage these new capabilities and, if so, how? Almost a year ago, we - along with John Quarto-vonTivadar - began work on a new version of Fusebox that would leverage the new capabilities of MX. At once there was a good deal of speculation on what "Fusebox MX" would look like. Would Fusebox become an OO framework? Would developers have to understand polymorphism and inheritance to use it? This article answers these questions and will, we hope, inspire people to look at a new, unashamedly object-oriented framework called Mach-II. In next month's issue of ColdFusion Developer's Journal, we'll explore Fusebox 4 - the worthy successor to Fusebox 3.

ColdFusion's initial appeal was to "Webmasters" who wanted to make their sites more dynamic - and it succeeded admirably. But just as the term "Webmaster" is an anachronism, the call for more dynamic Web sites was succeeded by the need for true Web applications.

As these applications became more involved and more ambitious in scope, ColdFusion developers discovered that even a thorough knowledge of tags and functions was just not enough. Realizing that the same problems presented themselves again and again, a group of developers wondered if these problems couldn't be solved - or at least ameliorated - by building some sort of framework on which Web-based applications could be developed. These visionaries traded ideas and code over e-mail. Ideas evolved and Fusebox was thus born, and it too succeeded admirably.

The Rise of OO
When ColdFusion MX was released, it generated a great deal of interest. For many developers, the most interesting aspect of the new release was the inclusion of a new encapsulation mechanism, the ColdFusion component (CFC). CFCs promised ColdFusion developers the ability to move from writing purely procedural code to object-oriented code. Macromedia began touting CFCs as "objects without all the fussiness."

For some developers, this represented a profound "this changes everything" shift - not without reason. Object orientation represents a shift in thinking. The procedural approach views each problem as a series of actions that must be taken in the correct order to achieve a desired result. Data is separate from functions. The object-oriented approach identifies separate, encapsulated components ("objects") in which data and functions are combined.

Fusebox represents a procedural approach to building applications. The object-oriented approach is very different from the procedural approach. Solutions result from first building classes that provide abstracted and simplified models of real-world counterparts. For example, a billing system might have classes for Invoice, Receipt, Customer, etc. When the application is run, instances of these classes (objects) are created. The running application then resembles an extended conversation between objects, with different objects sending messages to other objects to request information or ask that a service of some type be performed.

Shortly after the release of CFCs, we wrote "Discovering CFCs" (Techspedition Press, 2002), in which we explored in what ways CFCs were - and were not - truly object oriented. And since we were both involved in the Fusebox world, we decided to write a new version of Fusebox that would make use of the new capabilities of CFCs. We labeled the initiative, seemingly sensibly enough, Fusebox MX.

When we began talking about it openly, we heard from people who asked whether, with CFCs, the need for Fusebox was gone altogether? "Why do we need Fusebox when we have objects?" they asked. As we saw it, there were three ways to answer this question.

First, as we showed in our book, there were aspects of CFCs that simply could not be squared with an object-oriented approach. Second, if objects obviated the need for frameworks, why would Java, a language with first-class objects, have strong communities for over a dozen framework projects? Finally, however helpful individual components might be, they didn't address the issue of an underlying architecture. In short, we felt that Fusebox remained a valuable framework for the ColdFusion community.

OO and You
But a funny thing happened on the way to Fusebox MX. We began to ask questions about the appropriate software architecture on which to build the framework. Would Fusebox MX essentially be Fusebox - doing little more than adding components into a still procedural toolkit? That would be the easiest change for existing Fuseboxers to get used to, but would be little more than adding "super custom tags" to procedural code.

We felt strongly that the continued reliance on procedural code would put ColdFusion programmers at risk. Over the past 10 years, essentially the current lifespan of ColdFusion, a revolution has taken place. This revolution was not political, but technological, and it represented the ascension of object orientation as the dominant software construction paradigm. While languages such as Java, C#, Delphi, Visual Basic .NET, and Ruby (to name only a few) represented the new guard in this revolution, ColdFusion - and Fusebox - remained solidly procedural. Developers using ColdFusion simply didn't need to come to terms with object orientation.

Being involved in the Fusebox community, we felt a duty to ensure that Fuseboxers would not be using a proprietary framework cut off from the bigger IT world. We decided to rethink everything about Fusebox - including its architecture.

A Focus on Architecture
For many developers, the idea of "software architecture" simply means "how I put my application together." While obviously inexact, that definition of architecture was reflected by the great architect, Ludwig Mies van der Rohe, who wrote: "Whenever someone puts two bricks together, there architecture begins."

In practice, software architectures are commonly treated as a collection of components and connectors. Components are the system's functional elements, such as a shopping cart, a contact manager, or a database. Connectors define the protocols for communication between components. Examples of connectors include method calls, SQL queries, and HTTP requests. The architecture chosen for a system determines the vocabulary of components and connectors that can be used as well as the set of constraints defining how they are combined.

The choice of a particular software architecture is made on the basis of the goals of the designers, which is to say that there is no single-fit, perfect architecture. Over time, several different software architectural styles have risen to the fore, each with its own strengths and weaknesses. Our choice of a software architecture for a new Fusebox would then depend on what we wanted to accomplish. To determine this, we examined what others had come to rely on with Fusebox.

Fundamental Fusebox Goals
We began to speak with other Fuseboxers: What was it they most valued about Fusebox? From many voices, a few themes emerged. What Fuseboxers wanted from Fusebox was:

  • The ability to more rapidly develop applications: Developers voicing this concern told us that they were being asked to develop applications without sufficient time or resources. They were far less concerned about "future-proofing" their careers by learning OO than they were simply about getting out from under the current backlog of work.
  • The ability to help manage complexity: Simple apps are...well...simple, but they seldom remain simple. We've often noted that the most dangerous words clients can utter are, "You know what would be nice...." Despite our best efforts at requirements gathering, new requirements evolve and suddenly a simple application becomes more complex. Nor does ongoing development ever stop. Each new change becomes the basis for a new round of "improvements."
  • The ability to do effective team development: In corporate environments especially, application development is done by teams. Each member has unique strengths to offer, but very few have all the needed skills to solely craft an entire Web application. Any change to the current version of Fusebox needed to ensure that the support for team development was not diminished.
  • The ability to document an application: What developer wants to be forever chained to an application he or she has built? Yet without good documentation (and that meant documentation that was simple and easy to produce), developers were locked into maintaining their existing applications. It was simply too difficult for someone else to take over the responsibility for the application's maintenance.

    Our own concerns centered on software maintenance. It is an often overlooked fact that between 70-90% of the life-cycle cost of an application is spent on maintenance. A framework that misses this point, by treating maintenance as an afterthought, gives away the enormous leverage that cost and time savings in maintenance can offer adopters of the framework. And if saving money is not a worthy enough goal, surely saving the sanity of coders who must work on poorly maintained code is. Thus, software maintainability became one of our chief goals.

    Maintainability, we knew, was intimately tied to code reusability, since the same problem that causes an application to be difficult to maintain causes the components to be difficult to reuse - namely, the tight coupling between components.

    Excessive dependencies between code components adversely affects all. Therefore, we felt that by tackling software maintainability, we would increase the chances for significant code reuse.

    Cohesion and Coupling
    Two metrics important for consideration in defining the publicly exposed interfaces of an architecture's components and connectors are a system's cohesion and coupling. Cohesion is the measure of the degree to which a component has a singular purpose. The greater cohesion a component exhibits, the more focused the component and the fewer the assumptions about contexts for reuse.

    Coupling is the degree of interdependence between components. The less a component relies on other components (the looser its coupling), the more independent and reusable it is. Maximized cohesion (simple components) and minimized coupling (fewer connectors) are hallmarks of a flexible, maintainable architecture.

    One of the more broadly accepted architectural styles in software engineering is known as implicit invocation. Implicit invocation architectures intrigued us. Event-based, implicit invocation is an example of a well-crafted architectural style with high cohesion and loose coupling. As such, it is one of the more broadly accepted architectural styles in software engineering. Examples of implicit invocation systems abound, including virtually all modern operating systems, integrated development environments, and database management systems.

    Events and Listeners
    Implicit invocation systems rely on the idea of events and listeners. Events are triggered whenever the system needs to do something, such as respond to an incoming request. Events can take many forms across different types of implementations; often for object-based systems, an event is an object whose properties contain any contextual information needed to process the event (similar to how an HTTP request carries with it all its form and query-string variables).

    Listeners are business logic components that are registered with the system. When an event is announced, the system finds the listeners registered for that event and announces the new event to those listeners. Listeners fit the same criteria for components that we've already discussed - they are functional modules of the system. Components that wish to act as listeners are registered to listen for certain events at configuration time (by specification in an XML file, for instance). When an event is triggered, all registered listeners of that event are passed the event by means of a dynamically determined method call. In this way, functions are implicitly invoked. This process of notifying listeners of an event is called event announcement.

    Events and listeners can themselves trigger other events. Let's consider how a common login/authentication scenario can be represented in terms of events and listeners. In this example, a login form is filled out by a user and then submitted. The incoming HTTP request triggers the creation of a LoginEvent, and the system populates the event with information in the request.

    Next, the system determines the listeners for LoginEvent; in this case there is only one - the AuthenticationListener. Determined by a configuration file, the system invokes the AuthenticationListener's tryLogin() method, passing to it the event. Based on information in the event, the tryLogin() method will seek to authenticate the user. If the authentication succeeds, a new LoginAcceptedEvent is triggered. If authentication fails, a new LoginFailedEvent is triggered. The cycle then continues, with any listeners of the new event being notified (see Figure 1).

     

    Loosely coupled components work together, but do not rely on each other to do their own jobs. The interaction policy is separate from the interacting components, providing flexibility. Components can be introduced into a system simply by registering them for events of the system, aiding greatly in reusability and maintainability. Introduction of new components does not require change in other component interfaces, providing scalability as new features are added. Overall, implicit invocation eases system evolution.

    Rather than starting with the idea of making a Fusebox for ColdFusion MX, we began with the idea of making a true, object-oriented framework that would meet the goals we adopted. Work on the framework proceeded without regard to a specific language. Instead, we wanted to ensure that this new framework would be adaptable to any language that implemented object-oriented principles. Only after all architectural decisions were made did we set about the task of implementing it in ColdFusion, where we found CFCs provided us the encapsulation we needed.

    The end results have surprised and gratified us. We find that the system offers enormous flexibility. New functionality (a.k.a., "You know what would be nice...") is often as easy as adding a new listener to the system. Loose coupling ensures that other components do not need to be altered. We found that the implementation of the Model-View-Controller design pattern was a natural fit with an event-based invocation architecture. Finally, we found that the system could easily work with Web services, Flash remoting, Enterprise JavaBeans, and more.

    Only one problem remained: What should we call this new framework? We began this journey with the idea that we were creating a "Fusebox MX". What emerged was something different and better than what we had hoped for. But was it Fusebox MX? In the end, we decided that a different name would better serve all involved. Certainly, the underlying architecture had little in common with Fusebox. Better, we felt, to give it a separate name. Fusebox 4 would be the successor to Fusebox 3, and would continue to offer enormous benefits to procedural programmers.

    After too many late-night discussions (for some reason, naming something takes on enormous importance!), we decided that we wanted the framework name to reflect the fact that it was meant to help developers break the procedural barrier. Mach-II was thus born. Next month, we'll explore the inner workings of Mach-II. In the meantime, we invite developers who want to use a powerful, flexible, object-oriented framework to build robust and maintainable applications to explore Mach-II at www.mach-ii.com.

  • More Stories By Hal Helms

    Hal Helms is a well-known speaker/writer/strategist on software development issues. He holds training sessions on Java, ColdFusion, and software development processes. He authors a popular monthly newsletter series. For more information, contact him at hal (at) halhelms.com or see his website, www.halhelms.com.

    More Stories By Ben Edwards

    Ben Edwards is a Sun Certified Java Programmer and holds a degree in
    computer science from the Georgia Institute of Technology. He
    currently trains developers on software engineering practices
    focusing on Java, object-oriented programming, and software
    architectures. Ben is also cofounder of the Mach-II project.

    Comments (4) View Comments

    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.


    Most Recent Comments
    Jonathan Clough 10/13/03 08:31:18 AM EDT

    I've really benefitted from Fusebox3 and liked the idea of Mach-ii. However the mach-ii site has almost no documentation! Come on guys, if you want the programming community to take up Mach-ii then at least tell us how it works !!

    Sean Corfield 10/01/03 04:53:11 PM EDT

    Mach II does a very good job of abstracting the subtleties of the Implicit Invocation Architecture and the Model View Controller design pattern on which it is based.

    The end result is a well-defined framework that lets you build applications that are easy to maintain and enhance.

    CF Guy 09/15/03 04:14:40 PM EDT

    Whatever you want to. You are not forced to take advantage of the improvements in ColdFusion. While not the optimum usage, CF still has the same ability to be procedural if you like.

    Thomas Hamlin 08/24/03 07:56:10 PM EDT

    Gentlemen,

    The reason I was attracted to Coldfusion, Macromedia and Fusebox was that some of the complexity had been abstracted from what I thought I would need to do. It seems to be going the opposite direction. If I wanted to be a C++ OO programer I would have done that years ago. I want to run a business and be in touch with technology not be a slave to it.

    @ThingsExpo Stories
    The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
    The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
    Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
    Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
    IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...
    "We've discovered that after shows 80% if leads that people get, 80% of the conversations end up on the show floor, meaning people forget about it, people forget who they talk to, people forget that there are actual business opportunities to be had here so we try to help out and keep the conversations going," explained Jeff Mesnik, Founder and President of ContentMX, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
    With 15% of enterprises adopting a hybrid IT strategy, you need to set a plan to integrate hybrid cloud throughout your infrastructure. In his session at 18th Cloud Expo, Steven Dreher, Director of Solutions Architecture at Green House Data, discussed how to plan for shifting resource requirements, overcome challenges, and implement hybrid IT alongside your existing data center assets. Highlights included anticipating workload, cost and resource calculations, integrating services on both sides...
    Manufacturers are embracing the Industrial Internet the same way consumers are leveraging Fitbits – to improve overall health and wellness. Both can provide consistent measurement, visibility, and suggest performance improvements customized to help reach goals. Fitbit users can view real-time data and make adjustments to increase their activity. In his session at @ThingsExpo, Mark Bernardo Professional Services Leader, Americas, at GE Digital, discussed how leveraging the Industrial Internet a...
    Big Data engines are powering a lot of service businesses right now. Data is collected from users from wearable technologies, web behaviors, purchase behavior as well as several arbitrary data points we’d never think of. The demand for faster and bigger engines to crunch and serve up the data to services is growing exponentially. You see a LOT of correlation between “Cloud” and “Big Data” but on Big Data and “Hybrid,” where hybrid hosting is the sanest approach to the Big Data Infrastructure pro...
    "My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
    A critical component of any IoT project is what to do with all the data being generated. This data needs to be captured, processed, structured, and stored in a way to facilitate different kinds of queries. Traditional data warehouse and analytical systems are mature technologies that can be used to handle certain kinds of queries, but they are not always well suited to many problems, particularly when there is a need for real-time insights.
    The best-practices for building IoT applications with Go Code that attendees can use to build their own IoT applications. In his session at @ThingsExpo, Indraneel Mitra, Senior Solutions Architect & Technology Evangelist at Cognizant, provided valuable information and resources for both novice and experienced developers on how to get started with IoT and Golang in a day. He also provided information on how to use Intel Arduino Kit, Go Robotics API and AWS IoT stack to build an application tha...
    IoT generates lots of temporal data. But how do you unlock its value? You need to discover patterns that are repeatable in vast quantities of data, understand their meaning, and implement scalable monitoring across multiple data streams in order to monetize the discoveries and insights. Motif discovery and deep learning platforms are emerging to visualize sensor data, to search for patterns and to build application that can monitor real time streams efficiently. In his session at @ThingsExpo, ...
    You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
    Extracting business value from Internet of Things (IoT) data doesn’t happen overnight. There are several requirements that must be satisfied, including IoT device enablement, data analysis, real-time detection of complex events and automated orchestration of actions. Unfortunately, too many companies fall short in achieving their business goals by implementing incomplete solutions or not focusing on tangible use cases. In his general session at @ThingsExpo, Dave McCarthy, Director of Products...
    WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, discussed the importance of WebRTC and how it enables companies to focus...
    Amazon has gradually rolled out parts of its IoT offerings in the last year, but these are just the tip of the iceberg. In addition to optimizing their back-end AWS offerings, Amazon is laying the ground work to be a major force in IoT – especially in the connected home and office. Amazon is extending its reach by building on its dominant Cloud IoT platform, its Dash Button strategy, recently announced Replenishment Services, the Echo/Alexa voice recognition control platform, the 6-7 strategic...
    Verizon Communications Inc. (NYSE, Nasdaq: VZ) and Yahoo! Inc. (Nasdaq: YHOO) have entered into a definitive agreement under which Verizon will acquire Yahoo's operating business for approximately $4.83 billion in cash, subject to customary closing adjustments. Yahoo informs, connects and entertains a global audience of more than 1 billion monthly active users** -- including 600 million monthly active mobile users*** through its search, communications and digital content products. Yahoo also co...
    "There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
    SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.