|By Samuel Neff||
|April 3, 2003 12:00 AM EST||
Components bring to ColdFusion MX developers much of the power and practices of object-oriented programming. The component implementation in ColdFusion MX introduces us to many of the principles of OOP, including encapsulation and inheritance. One aspect of these features is the ability to create new components that inherit or extend the functionality of other components.
In order to effectively extend functionality, developers often require the ability to override existing component functions as well as still call the original functions to incorporate their programming logic. Since ColdFusion MX doesn't currently provide this ability, we'll explore a technique to work around this limitation that enables us to call a parent component's overridden method.
With component-based development, related code can easily be grouped together in a consolidated entity, giving us the ability to encapsulate data and functionality. This consolidation can be further expanded with the ability to inherit functionality from a parent component, also called extension. When one component extends another, it can both reuse the functionality of the original component and add its own functionality.
Often, the new functionality added to a component will replace its original functionality. This is an advantage to developers who utilize the component in their code since the parent and child components will each have a similar call interface, or function names. By maintaining a consistent interface, developers can write code that can use either the parent or child component interchangeably without modifying the calling code.
For an example of this, see Listing 1, which sets up two components, GreetingBase.cfc and GreetingChild.cfc. GreetingChild extends the functionality of GreetingBase, and both provide a single function, sayGreeting, which returns a greeting to the caller. The caller can use either component and call the same function to retrieve the result appropriate for the component being used, a feature known in OOP as polymorphism.
Calling Overridden Parent Component Functions
We run into a limitation when we try to utilize the parent component functionality for a function that we've overridden, in this case sayGreeting. We want to add a function sayAllGreetings, which returns the results of both the parent and the child components' sayGreeting functions. While you can create an instance of the parent component and call the new instance's sayGreeting method, this would not return accurate results in cases where the call depends on data in the component instance. Unfortunately, there is no mechanism in ColdFusion MX to call an overridden parent method and have it run in the context of the calling component instance.
Many other OOP languages, such as Java and even ActionScript, allow calling a parent class's methods through the keyword Super. While ColdFusion MX does not provide this ability, there is an often-overlooked feature that we can use to achieve the desired effect.
ColdFusion stores function references and variables equally. A function can be called by referring to the function name followed by parentheses, as you are accustomed. Additionally, the function reference can also be utilized by simply referring to the function name. The most common utilization of this feature is to copy a function to another scope, and here we'll use this ability to make a parent component's functions available to its children.
Any code that exists within the cfcomponent tags and outside of any cffunction tags is executed when the component is instantiated. This code is most often used to set up or initialize the component and is called the Constructor in OOP terms.
<!--- constructor code goes here --->
In Listing 2 we added some code to our original components. GreetingBase.cfc now has two lines of code in the constructor.
<cfset super = structNew()>
<cfset super.sayGreeting = sayGreeting>
What we've done here is set up a structure called "super", which we'll use as a holder for our parent component methods. After creating the structure we use cfset to copy a reference to the function to our structure. It's important to note here that when this code is run, the component will exist only as the parent component, so any functionality that is overridden in the child component has not yet been incorporated.
With this structure created and our parent functions safely stored, we can utilize them in the child, GreetingChild.cfc, as follows:
<cfset var greetings="Parent says '" &
"', Child says '" &
sayGreeting() & "'">
In this code we put together a string in which we call our parent component's sayGreeting function, through our super structure, and also call the current sayGreeting function as we normally would.
Super Structure Limitations
Through a little creative utilization of obscure features, we've been able to implement a very important feature common to OOP. However, our implementation is not comprehensive and does have limitations.
This technique can only be used to implement one level of parent-component calls. Since each component in the inheritance chain does not have its own data location where we can store the parent component's methods, we can only store the methods from a single parent component.
Additionally, we must recognize that this is a workaround to provide for functionality missing from ColdFusion MX. Since this feature is standard for OOP and commonly requested from developers, Macromedia will probably implement this functionality natively in a future version of ColdFusion.
When adding support for parent-component calls, Macromedia is likely to use the keyword "super" in their own implementation since this is used in both Java and ActionScript. With this change, our code will stop working since "super" will become a keyword. While this may seem like a problem, it is actually an advantage.
Since we no longer need our workaround once parent component calls are implemented in ColdFusion, we want to ensure that we can easily remove this workaround when it becomes obsolete. To accomplish this, wrap all of the super workaround code, the parent-component constructor, inside consistent comments as shown in Listing 3.
With these comments, we can utilize the Regular Expression replace in either ColdFusion Studio or Dreamweaver to remove all of the super structures from our code. As long as the keyword super is used for this functionality natively, the rest of our code will continue to work.
Component-based development brings to ColdFusion MX many of the features of OOP. By using a structure and function references, we were able to bring a common feature of OOP to ColdFusion, albeit with limitations. In recognizing these limitations, we can write our code in a forward-thinking manner and facilitate future changes to the code when they come in conflict with possible new functionality.
SYS-CON Events announced today that Ciqada will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Ciqada™ makes it easy to connect your products to the Internet. By integrating key components - hardware, servers, dashboards, and mobile apps - into an easy-to-use, configurable system, your products can quickly and securely join the internet of things. With remote monitoring, control, and alert messaging capability, you will meet your customers' needs of tomorrow - today! Ciqada. Let your products take flight. For more inform...
Apr. 18, 2015 07:00 AM EDT Reads: 1,540
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
Apr. 18, 2015 06:00 AM EDT Reads: 2,217
SYS-CON Events announced today that BroadSoft, the leading global provider of Unified Communications and Collaboration (UCC) services to operators worldwide, has been named “Gold Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. BroadSoft is the leading provider of software and services that enable mobile, fixed-line and cable service providers to offer Unified Communications over their Internet Protocol networks. The Company’s core communications platform enables the delivery of a range of enterprise and consumer calling...
Apr. 18, 2015 05:30 AM EDT Reads: 2,147
VoxImplant has announced full WebRTC support in the newest versions of its Android SDK and iOS SDK. The updated SDKs, which enable audio and video calls on mobile devices, are now compatible with the WebRTC standard to allow any mobile app to communicate with WebRTC-enabled browsers, including Google Chrome, Mozilla Firefox, Opera, and, when available, Microsoft Spartan. The WebRTC-updated SDKs represent VoxImplant's continued leadership in simplifying the development of real-time communications (RTC) services for app developers. VoxImplant (built by Zingaya, the real-time communication servi...
Apr. 18, 2015 02:45 AM EDT Reads: 1,785
The IoT Bootcamp is coming to Cloud Expo | @ThingsExpo on June 9-10 at the Javits Center in New York. Instructor. Registration is now available at http://iotbootcamp.sys-con.com/ Instructor Janakiram MSV previously taught the famously successful Multi-Cloud Bootcamp at Cloud Expo | @ThingsExpo in November in Santa Clara. Now he is expanding the focus to Janakiram is the founder and CTO of Get Cloud Ready Consulting, a niche Cloud Migration and Cloud Operations firm that recently got acquired by Aditi Technologies. He is a Microsoft Regional Director for Hyderabad, India, and one of the f...
Apr. 18, 2015 01:00 AM EDT Reads: 895
SYS-CON Events announced today that Optimal Design, an Internet of Things solution provider, will exhibit at SYS-CON's Internet of @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Optimal Design is an award winning product development firm offering industrial design and engineering services to the consumer, medical, and defense markets.
Apr. 17, 2015 05:30 PM EDT Reads: 1,566
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
Apr. 17, 2015 02:00 PM EDT Reads: 1,314
What exactly is a cognitive application? In her session at 16th Cloud Expo, Ashley Hathaway, Product Manager at IBM Watson, will look at the services being offered by the IBM Watson Developer Cloud and what that means for developers and Big Data. She'll explore how IBM Watson and its partnerships will continue to grow and help define what it means to be a cognitive service, as well as take a look at the offerings on Bluemix. She will also check out how Watson and the Alchemy API team up to offer disruptive APIs to developers.
Apr. 17, 2015 12:00 PM EDT Reads: 1,394
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps 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 opportunity. Submit your speaking proposal today!
Apr. 17, 2015 12:00 PM EDT Reads: 2,042
With IoT exploding, massive data will transform businesses with opportunities to monetize almost anything that can be measured. In this C-Level Roundtable Discussion at @ThingsExpo, Brendan O’Brien, Aria Systems Co-founder and Chief Evangelist, will lead an expert panel of consultants, thought leaders and practitioners who will look at these new monetization trends, discuss the implications, and detail lessons learned from their collective experience. Finally, the panel will point the way forward for enterprises who wish to leverage the resulting complex recurring revenue models, adding valu...
Apr. 17, 2015 11:15 AM EDT Reads: 1,370
How is unified communications transforming the way businesses operate? In his session at WebRTC Summit, Arvind Rangarajan, Director of Product Marketing at BroadSoft, will discuss how to extend unified communications experience outside the enterprise through WebRTC. He will also review use cases across different industry verticals. Arvind Rangarajan is Director, Product Marketing at BroadSoft. He has over 19 years of experience in the telecommunications industry in various roles such as Software Development, Product Management and Product Marketing, applied across Wireless, Unified Communic...
Apr. 17, 2015 09:45 AM EDT Reads: 1,535
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? Join this panel of experts as they peel away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud environment, and we must architect and code accordingly. At the very least, you’ll have no problem filling in your buzzword bingo cards.
Apr. 16, 2015 05:30 PM EDT Reads: 2,101
Internet of Things (IoT) will be a hybrid ecosystem of diverse devices and sensors collaborating with operational and enterprise systems to create the next big application. In their session at @ThingsExpo, Bramh Gupta, founder and CEO of robomq.io, and Fred Yatzeck, principal architect leading product development at robomq.io, will discuss how choosing the right middleware and integration strategy from the get-go will enable IoT solution developers to adapt and grow with the industry, while at the same time reduce Time to Market (TTM) by using plug and play capabilities offered by a robust I...
Apr. 13, 2015 12:15 PM EDT Reads: 1,874
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this case) takes into account the number and quality of contextual references that a user receives.
Apr. 12, 2015 04:00 PM EDT Reads: 1,895
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet conditions, Dyn ensures traffic gets delivered faster, safer, and more reliably than ever.
Apr. 11, 2015 09:15 AM EDT Reads: 2,224
IoT is still a vague buzzword for many people. In his session at @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, discussed the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. He also discussed how IoT is perceived by investors and how venture capitalist access this space. Other topics discussed were barriers to success, what is new, what is old, and what the future may hold. Mike Kavis is Vice President & Principal Cloud Architect at Cloud Technology Pa...
Apr. 11, 2015 09:00 AM EDT Reads: 6,011
The only place to be June 9-11 is Cloud Expo & @ThingsExpo 2015 East at the Javits Center in New York City. Join us there as delegates from all over the world come to listen to and engage with speakers & sponsors from the leading Cloud Computing, IoT & Big Data companies. Cloud Expo & @ThingsExpo are the leading events covering the booming market of Cloud Computing, IoT & Big Data for the enterprise. Speakers from all over the world will be hand-picked for their ability to explore the economic strategies that utility/cloud computing provides. Whether public, private, or in a hybrid form, clo...
Apr. 8, 2015 02:30 PM EDT Reads: 3,990
The WebRTC Summit 2015 New York, to be held June 9-11, 2015, at the Javits Center in New York, NY, announces that its Call for Papers is open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 16th International Cloud Expo, @ThingsExpo, Big Data Expo, and DevOps Summit.
Apr. 8, 2015 09:00 AM EDT Reads: 2,272
As Marc Andreessen says software is eating the world. Everything is rapidly moving toward being software-defined – from our phones and cars through our washing machines to the datacenter. However, there are larger challenges when implementing software defined on a larger scale - when building software defined infrastructure. In his session at 16th Cloud Expo, Boyan Ivanov, CEO of StorPool, will provide some practical insights on what, how and why when implementing "software-defined" in the datacenter.
Apr. 7, 2015 12:00 PM EDT Reads: 1,488
While not quite mainstream yet, WebRTC is starting to gain ground with Carriers, Enterprises and Independent Software Vendors (ISV’s) alike. WebRTC makes it easy for developers to add audio and video communications into their applications by using Web browsers as their platform. But like any market, every customer engagement has unique requirements, as well as constraints. And of course, one size does not fit all. In her session at WebRTC Summit, Dr. Natasha Tamaskar, Vice President, Head of Cloud and Mobile Strategy at GENBAND, will explore what is needed to take a real time communications ...
Apr. 6, 2015 10:00 AM EDT Reads: 1,642