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

component.cfc: The Mother of All Components

component.cfc: The Mother of All Components

Yes, that's right, components have mommies and daddies. Well, not really, but that statement isn't too far from the truth. This article explains "component.cfc", a hidden gem in the ColdFusion Component architecture that is part of ColdFusion MX.

By now, everybody knows that the introduction of the component framework in ColdFusion MX was one of the most radical changes to CFML since its inception. Their introduction was significant for three primary reasons. First, they allow developers to expose functionality to the Flash Gateway and to any other Web service-enabled environment. Second, they offer a level of abstraction far superior to that of custom tags and user-defined functions. The third reason CFCs have made such an impact on CFML is that they offer ColdFusion developers the ability to implement object-oriented features.

These object-oriented features include new variable scopes with varying degrees of exposure outside the component; the "packaging" of functionality, introspection, and the generation of meta data; objectinstance- based programming; and inheritance. In traditional object-oriented programming languages, all objects inherit from a parent "Object" class. What many developers don't realize is that components, too, have a parent "class". Its name is "component.cfc" and it can be a very valuable tool when developing applications.

Where Can I Find component.cfc?
If you create a CFC that does not inherit from any other CFC and you view its meta data, you'll notice that the value for the "hierarchy" meta information defaults to "WEB-INF.cftags.component". You will find this file in the "CfusionMXWWWRootWEBINFcftags" directory if you're running the standalone version of ColdFusion, and in "JRun4servers{your_server_name}cfusion-earcfusion-warWEBINF cftags" if you're running the J2EE version (on top of JRun4). You can view the meta data for component.cfc on a server by browsing http://{server_domain}/CFIDE/componentutils/cfcexplorer.cfc?method=getcf cinhtml&name=WEB-INF.cftags.component, replacing "{server_domain}" with "localhost:8500" or whatever other URL you use to browse to that machine.

What Does component.cfc Do?
Well, nothing really. Not out of the box, anyway. The component.cfc file is empty by default in ColdFusion MX 6.1. In ColdFusion MX it had a tiny bit of encrypted data at the top of the file. As already discussed, all components inherit from component. cfc by default. Think of it as the Application.cfm of components - a place to put code that is implicitly included. The difference is that the code outside of any method in component.cfc is executed only when a ColdFusion Component is first initialized, and that its methods and meta data are inherited by other components. It gives you a single place to put code that must be common to all CFCs on your server.

Why Would I Want to Do That?
Having one place to put functionality and initialization code that will be available to all server components has two important uses. As already mentioned, you can think of it as similar to Application.cfm, which means that if you're running a server that's dedicated to hosting one application and the application is using CFCs for its business logic (as every application should be), it's a very good place to put functionality that all components need to have.

For example, if your server is hosting your company's public Web site, all of your components might need to have access to the current company catalog of products. Creating a method in component.cfc that retrieves the current catalog information from a database and returns it to the caller would ensure that all components have the ability to retrieve the catalog by calling that method. While this is a neat trick, it's not always terribly useful or desirable, especially when your application is running on a server that hosts other completely separate ColdFusion applications.

There's another use for component.cfc though - when wielded properly, it can be a powerful development tool. More than anything else, I like to put debugging methods in my component.cfc file so that they are available in any application I happen to be working on. Extending the component framework with development tools can make a developer's life a little bit easier, as we will soon see.

Coding with component.cfc
It's a little known fact that ColdFusion Components don't technically require a start and end <cfcomponent> tag… they will work without them. That said, without the <cfcomponent> tag, a CFC will not properly inherit from the base component. cfc file nor will it allow the use of <cfproperty> tags if you are defining meta information, so as a best practice, follow the standard recommended practices when creating components.

By default, component.cfc is an empty file. Because it does not inherit from any other component (after all, it is the mother of all components), you can code methods in the file without adding any <cfcomponent> tags. You can optionally add <cfcomponent> tags to component.cfc in order to generate meta data about the component or to enable the use of <cfproperty> tags before your methods. Like inheritence with other CFCs, any meta information, methods, and variables in the component are inherited by all other components on the server.

As you may have guessed, creating a method in one component with the same name as a method in component.cfc will override the method. The original method defined in component.cfc can be accessed with the "super" keyword as "super.methodName()", provided that the component you are in does not inherit from any other component. Let's examine one very practical use for this master component file.

Component.cfc Uses
If you're anything like me, you use <cfscript> a lot. As wonderful as <cfscript> is, it is not without limitations. In particular, the use of tags is strictly forbidden within a <cfscript> block. It is often necessary during the development process to view data in order to determine what's happening in your code. The <cfdump> tag is perfect for this, but wait - you cannot <cfdump> within a <cfscript> block. What to do?

Developers like me who use <cfscript> often, have made it a standard practice to create a function using <cffunction> that accepts a single argument of any data type, <cfdump> that variable, then <cfabort> the page. That function can then be called from <cfscript>, thus giving developers the ability to "see what's happening" within their <cfscript> code.

Here's the code I wrote inside of my component.cfc file so that I can dump a value from any ColdFusion Component <cfscript> block:

<cfcomponent displayname="Root" hint="Root CFC">
<!---:: function to dump then abort ::--->
<cffunction name="dumpIt" output="true" displayname="Dump It" hint="A
debugging tool" access="private" returntype="void">
<cfargument name="it" displayname="It" hint="The Thing To Dump"
required="true" type="any">
<cfdump var="#arguments.it#">

You'll notice that the method is private because I do not need nor want to expose it to cfm pages that are instantiating my components. It also means that the method does not display along with the other methods of a component that's inherited it when that component's meta data is browsed.

The "dumpIt()" method is useful for developers who do not use <cfscript> as well. It is generally considered a best practice to encapsulate business logic with components. This means passing a value to a component method, operating on that value, and returning a value to the caller page or application. With this in mind, it's a safe assumption that the components in your application(s) aren't directly outputting anything to the HTTP output stream.

Pretty much every component I create not only uses <cfscript> heavily, but never outputs anything. To make sure nothing is output, I always set my <cffunction> tag "output" attributes to "false". This is definitely a best practice in most scenarios, but not being able to output directly from a component method also means you cannot <cfdump> the value of variables within the component when you're debugging your application. Once again, the "dumpIt()" method is a very handy tool, as from within a "silent" component, you can pass the suspicious variable to this method (which has the "output" attribute set to "true") in order to see what's going on in your code.

Where Do We Go from Here?
Component.cfc is a very practical debugging tool for developers and can also be a powerful part of your applications as well. We have looked at just one way that it can be used as an effective development tool. You could create variations of the "dumpIt()" function so that you have one method to dump and abort and another to dump and allow processing to continue. It wouldn't be difficult to add methods to your component.cfc that allow you to do other useful things such as time blocks of code using the getTickCount() function, for example.

Be forewarned that there are two major drawbacks to placing code, especially application rather than debugging/development code, in component.cfc. One is that from an architectural point of view, you are physically separating your code from the rest of your application business logic. The other is that you are making your code less portable - it's no longer a simple matter of copying a directory structure from one server to another in order to move your application when some of the logic is housed in component. cfc. Other than that, have fun and take advantage of it! The sky's the limit.

More Stories By Simon Horwith

Simon Horwith is the CIO at AboutWeb, LLC, a Washington, DC based company specializing in staff augmentation, consulting, and training. Simon is a Macromedia Certified Master Instructor and is a member of Team Macromedia. He has been using ColdFusion since version 1.5 and specializes in ColdFusion application architecture, including architecting applications that integrate with Java, Flash, Flex, and a myriad of other technologies. In addition to presenting at CFUGs and conferences around the world, he has also been a contributing author of several books and technical papers.

Comments (0)

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.

@ThingsExpo Stories
The Open Connectivity Foundation (OCF), sponsor of the IoTivity open source project, and AllSeen Alliance, which provides the AllJoyn® open source IoT framework, today announced that the two organizations’ boards have approved a merger under the OCF name and bylaws. This merger will advance interoperability between connected devices from both groups, enabling the full operating potential of IoT and representing a significant step towards a connected ecosystem.
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 ...
A completely new computing platform is on the horizon. They’re called Microservers by some, ARM Servers by others, and sometimes even ARM-based Servers. No matter what you call them, Microservers will have a huge impact on the data center and on server computing in general. Although few people are familiar with Microservers today, their impact will be felt very soon. This is a new category of computing platform that is available today and is predicted to have triple-digit growth rates for some ...
SYS-CON Events announced today that Roundee / LinearHub will exhibit at the WebRTC Summit at @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LinearHub provides Roundee Service, a smart platform for enterprise video conferencing with enhanced features such as automatic recording and transcription service. Slack users can integrate Roundee to their team via Slack’s App Directory, and '/roundee' command lets your video conference ...
SYS-CON Events announced today that Enzu 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. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive advantage. By offering a suite of proven hosting and management services, Enzu wants companies to focus on the core of their online busine...
SYS-CON Events announced today that SoftNet Solutions 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. SoftNet Solutions specializes in Enterprise Solutions for Hadoop and Big Data. It offers customers the most open, robust, and value-conscious portfolio of solutions, services, and tools for the shortest route to success with Big Data. The unique differentiator is the ability to architect and...
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
In past @ThingsExpo presentations, Joseph di Paolantonio has explored how various Internet of Things (IoT) and data management and analytics (DMA) solution spaces will come together as sensor analytics ecosystems. This year, in his session at @ThingsExpo, Joseph di Paolantonio from DataArchon, will be adding the numerous Transportation areas, from autonomous vehicles to “Uber for containers.” While IoT data in any one area of Transportation will have a huge impact in that area, combining senso...
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
@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 ...
The IoT has the potential to create a renaissance of manufacturing in the US and elsewhere. In his session at 18th Cloud Expo, Florent Solt, CTO and chief architect of Netvibes, discussed how the expected exponential increase in the amount of data that will be processed, transported, stored, and accessed means there will be a huge demand for smart technologies to deliver it. Florent Solt is the CTO and chief architect of Netvibes. Prior to joining Netvibes in 2007, he co-founded Rift Technologi...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
Established in 1998, Calsoft is a leading software product engineering Services Company specializing in Storage, Networking, Virtualization and Cloud business verticals. Calsoft provides End-to-End Product Development, Quality Assurance Sustenance, Solution Engineering and Professional Services expertise to assist customers in achieving their product development and business goals. The company's deep domain knowledge of Storage, Virtualization, Networking and Cloud verticals helps in delivering ...
24Notion is full-service global creative digital marketing, technology and lifestyle agency that combines strategic ideas with customized tactical execution. With a broad understand of the art of traditional marketing, new media, communications and social influence, 24Notion uniquely understands how to connect your brand strategy with the right consumer. 24Notion ranked #12 on Corporate Social Responsibility - Book of List.
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smar...
@ThingsExpo has been named the Top 5 Most Influential M2M Brand by Onalytica in the ‘Machine to Machine: Top 100 Influencers and Brands.' Onalytica analyzed the online debate on M2M by looking at over 85,000 tweets to provide the most influential individuals and brands that drive the discussion. According to Onalytica the "analysis showed a very engaged community with a lot of interactive tweets. The M2M discussion seems to be more fragmented and driven by some of the major brands present in the...
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
In the next five to ten years, millions, if not billions of things will become smarter. This smartness goes beyond connected things in our homes like the fridge, thermostat and fancy lighting, and into heavily regulated industries including aerospace, pharmaceutical/medical devices and energy. “Smartness” will embed itself within individual products that are part of our daily lives. We will engage with smart products - learning from them, informing them, and communicating with them. Smart produc...
In his keynote at 19th Cloud Expo, Sheng Liang, co-founder and CEO of Rancher Labs, will discuss the technological advances and new business opportunities created by the rapid adoption of containers. With the success of Amazon Web Services (AWS) and various open source technologies used to build private clouds, cloud computing has become an essential component of IT strategy. However, users continue to face challenges in implementing clouds, as older technologies evolve and newer ones like Docke...
As ridesharing competitors and enhanced services increase, notable changes are occurring in the transportation model. Despite the cost-effective means and flexibility of ridesharing, both drivers and users will need to be aware of the connected environment and how it will impact the ridesharing experience. In his session at @ThingsExpo, Timothy Evavold, Executive Director Automotive at Covisint, will discuss key challenges and solutions to powering a ride sharing and/or multimodal model in the a...