April 2009


Introduction:

MVC is an architectural pattern used in software engineering. In complex computer applications that present lots of data to the user, one often wishes to separate data (model) and user interface (view) concerns, so that changes to the user interface do not impact the data handling, and that the data can be reorganized without changing the user interface. The model-view-controller solves this problem by decoupling data access and business logic from data presentation and user interaction, by introducing an intermediate component: the controller.

The MVC paradigm is a way of breaking an application, or even just a piece of an application’s interface, into three parts: the model, the view, and the controller.

MVC was originally developed to map the traditional input, processing, output roles into the GUI realm:
mvc model controller view joomla15

Input –> Processing –> Output
Controller –> Model –> View

Model

The model is the part of the component that encapsulates the application’s data. It will often provide routines to manage and manipulate this data in a meaningful way in addition to routines that retrieve the data from the model. In our case, the model will contain methods to add, remove and update information about the books in the database. It will also contain methods to retrieve the list of books from the database. In general, the underlying data access technique should be encapsulated in the model. In this way, if an application is to be moved from a system that utilizes a flat file to store its information to a system that uses a database, the model is the only element that needs to be changed, not the view or the controller.

View

The view is the part of the component that is used to render the data from the model in a manner that is suitable for interaction. For a web-based application, the view would generally be an HTML page that is returned to the data. The view pulls data from the model (which is passed to it from the controller) and feeds the data into a template which is populated and presented to the user. The view does not cause the data to be modified in any way, it only displays data retrieved from the model.

Controller

The controller is responsible for responding to user actions. In the case of a web application, a user action is a page request. The controller will determine what request is being made by the user and respond appropriately by triggering the model to manipulate the data appropriately and passing the model into the view. The controller does not display the data in the model, it only triggers methods in the model which modify the data.

Joomla! MVC Implementation

In Joomla!, the MVC pattern is implemented using three classes:

1. JModel
2. JView
3. and JController

Hello world component

a) structure

¦   com_helloworld.xml (xml – installation source)
¦
+—admin                       – (administration folder)
¦   ¦  index.html – (blank file)
¦   ¦   admin.helloworld.php – (create controller and hand over the control)
¦   ¦   toolbar.helloworld.php  – (tool bar definition and a ‘help’ menu item)
¦   ¦   toolbar.helloworld.html.php   – (tool bar definition and a ‘help’ menu item)
¦   ¦
¦   +—images                  – (here are all picures used in the component)
¦   ¦       helloworld.png
¦   ¦       index.html          – (blank file)
¦   ¦
¦   +—controllers             – (controlers folder)
¦   ¦       default.php         – (default controler      – “default section”)
¦   ¦       helloagain.php      – (heloagain controler    – “helloagain section”)
¦   ¦       hellotestfoo.php    – (hellotestfoo controler – “helhellotestfooloagain sec.”)
¦   ¦       helloworld.php      – (helloworld controler   – “helloworld section”)
¦   ¦
¦   +—models                  – (models folder)
¦   ¦       helloworld.php      – (the only model defined here. Currently not in use)
¦   ¦
¦   +—views                   – (views folder)
¦   ¦   +—default
¦   ¦   ¦       view.php        – (default view      – “default section”)
¦   ¦   ¦
¦   ¦   +—helloagain
¦   ¦   ¦       view.php        – (helloagain view   – “helloagain section”)
¦   ¦   ¦
¦   ¦   +—hellotestfoo
¦   ¦   ¦       view.php        – (hellotestfoo view – “hellotestfoo section”)
¦   ¦   ¦
¦   ¦   +—helloworld
¦   ¦           view.php        – (helloworld view   – “helloworld section”)
¦   ¦
¦   +—sql – (SQL folder. Currently not in use. All sql files)
¦   ¦       uninstall.helloworld.sql      ( are commented out in the installation xml.)
¦   ¦       install.helloworld.sql        ( The reasson is very simple. Joomla! 1.5 has )
¦   ¦                                     ( a minor bug in installation.php. We will need )
¦   ¦                                     ( a “night build” for the next tutorial)
¦   ¦
¦   +—lang – (language folder)
¦           cs-CZ.com_helloworld.ini    – (czech text package)
¦           en-GB.com_helloworld.ini    – (english text package)
¦
+—component
¦   index.html                      – (blank file)
¦   helloworld.php                  – (core for the frontend application. )
¦                                     ( Prints “hello world”.)
+—lang
cs-CZ.com_helloworld.ini    – (czech text package)
en-GB.com_helloworld.ini    – (english text package)

b) concept
We need to rewrite the core of our previous component. It prints “hello world” by accessing methods of class helloScreens in admin.helloworld.html.php

class helloScreens
{
function helloworld()
{ echo JText::_(‘helloworld’); }

function helloagain()
{ echo JText::_(‘helloagain’); }

function hellotestfoo()
{ echo JText::_(‘hellotestfoo’); }

function hellodefault()
{ echo JText::_(‘hellodefault’); }
}

All these methods will become stand-alone views. \views\helloworld\view.php

class HelloWorldComponentView extends JView
{

function display()
{
echo JText::_(‘helloworld’);
}
}

Are you a customer or partner of IT?

If you answered “customer,” guess again. IT only has one customer — and that is the customer who buys the company’s products and services. Serving this customer requires an effective IT-business partnership.

As a wise old client of mine articulately states, “IT should be of service, but not subservient.”

Of course, it’s much more enjoyable (and simpler) to be a customer than a partner. The thought of having to understand the long-term interests, workload, and challenges of my financial planner, gardener or babysitter is depressing. Why should I? The service is well defined and pretty commoditized. If my needs are not met, it’s easy to pick up the phone and move on. Although there are components of IT that are of a commodity nature (e.g., computer and network services), how a business applies technology to support their business processes and improve the performance of their people is not.

Partners take care of each other. Partners are committed to finding win-win solutions and making it work for the long term. They make sure that their plans, priorities, authorities, processes, and people dovetail. When problems arise, they fight the temptation to place blame and instead examine the context and system that allow great people to stumble and fall.

The bonus for strengthening the IT-business partnership is on line leaders. IT has practically tied their organizations into pretzels trying to crack the alignment code by trying to:

* Link IT and business strategies
* Shift authority for key IT decisions to business leaders (e.g., funding, priorities, functionality, service levels)
* Define IT services and processes to clarify respective roles and responsibilities and help ensure consistent, predictable delivery
* Decentralize application services to mirror the structure of the business
* Hire, develop, and reward business and relationship management skills (vs. technical skills)

In spite of their efforts over a long period of time, IT hasn’t figured out how to insert themselves in a real way in your real world. Every CIO and IT leader worth their weight understands that they should spend at least ½ of their time outside of the four walls of IT working with their business partners on planning, executing, and trouble-shooting. When challenged to do so, they sheepishly admit that they don’t know what to say and do. I have had many a CIO ask me, “What do I say?” They shy away from spearheading enterprise IT strategy, joint IT-business leadership development forums, IT-business job rotation, and believe it or not, co-location. To many, these efforts make them feel like they are inviting themselves to a party where they aren’t really welcome.

As a result, IT feels like a provider rather than a partner. They are dying for a “seat at the table” in decision-making so that they can advise you as to how to best achieve your goals and support enterprise interests, leverage current capabilities, and exploit new technologies.

IT has done pretty much everything they know how to do. Unless business leaders commit to forging a better partnership with IT, whatever IT is today, it will still be tomorrow.

As daunting as this may sound, the truth is that business leaders have always wanted more control over IT, as evidenced by their willingness to create “shadow” IT organizations, select technologies without involving IT, and contract directly with vendors.

IT-smart business leaders make sure that their organizations work seamlessly with IT. They invest in building strong relationships and teamword with IT because they understand that that IT is an organizational asset, not simply an organization structure, and that exploitation of this asset requires effective IT-business collaboration across, up and down the organization.

Taxonomy is the practice and science of classification. The word finds its roots in the Greek τάξις, taxis (meaning ‘order‘, ‘arrangement‘) and νόμος, nomos (‘law‘ or ‘science‘). Taxonomy uses taxonomic units, known as taxa (singular taxon).

In addition, the word is also used as a count noun: a taxonomy, or taxonomic scheme, is a particular classification (“the taxonomy of …”), arranged in a hierarchical structure. Typically this is organised by subtype-supertype relationships, also called parent-child relationships. In such a subtype-supertype relationship the subtype kind of thing has by definition the same constraints as the supertype kind of thing plus one or more additional constraints. For example, car is a subtype of vehicle. So any car is also a vehicle, but not every vehicle is a car. Therefore, a thing needs to satisfy more constraints to be a car than to be a vehicle.

Applications

Originally the term taxonomy referred only to the classifying of organisms (now sometimes known as alpha taxonomy) or a particular classification of organisms. However, it has become fashionable in certain circles to apply the term in a wider, more general sense, where it may refer to a classification of things or concepts, as well as to the principles underlying such a classification.

Almost anything — animate objects, inanimate objects, places, concepts, events, properties, and relationships — may be then classified according to some taxonomic scheme

In an even wider sense, the term taxonomy could also be applied to relationship schemes other than parent-child hierarchies, such as network structures with other types of relationships. Taxonomies may then include single children with multi-parents, for example, “Car” might appear with both parents “Vehicle” and “Steel Mechanisms”; to some however, this merely means that ‘car’ is a part of several different taxonomies. A taxonomy might also be a simple organization of kinds of things into groups, or even an alphabetical list. However, the term vocabulary is more appropriate for such a list. In current usage within “Knowledge Management”, taxonomies are seen as less broad than ontologies as ontologies apply a larger variety of relation types.

Mathematically, a hierarchical taxonomy is a tree structure of classifications for a given set of objects. It is also named Containment hierarchy. At the top of this structure is a single classification, the root node, that applies to all objects. Nodes below this root are more specific classifications that apply to subsets of the total set of classified objects. The progress of reasoning proceeds from the general to the more specific. In scientific taxonomies, a conflative term is always a polyseme.

In contrast, in a context of legal terminology, an open-ended contextual taxonomy — a taxonomy holding only with respect to a specific context. In scenarios taken from the legal domain, a formal account of the open-texture of legal terms is modeled, which suggests varying notions of the “core” and “penumbra” of the meanings of a concept. The progress of reasoning proceeds form the specific to the more general.

Go ahead just leave, can’t hold you, you’re free
You take all these things, if they mean so much to you
I gave you your dreams, ’cause you meant the world
So did I deserve to be left here hurt?

You think I don’t know you’re out of control
I ended up finding all of this from my boys
Girl, you’re stone cold, you say it ain’t so
You already know I’m not attached to material

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love, my love
My love

Yeah, what did I do but give love to you?
I’m just confused as I stand here and look at you
From head to feet, all that’s not me
Go ‘head, keep the keys, that’s not what I need from you

You think that you know
(I do)
You’ve made yourself cold
(Oh yeah)
How could you believe them over me, I’m your girl

You’re out of control
(So what?)
How could you let go?
(Oh yeah)
Don’t you know I’m not attached to material?

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love, my love

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love, my love

So all this love I give you, take it away
(Uh, uh huh)
You think material’s the reason I came
(Uh, uh huh)

If I had nothing would you want me to stay
(Uh, uh huh)
You keep your money, take it all away

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love

I’d give it all up but I’m takin’ back my love
I’m takin’ back my love, I’m takin’ back my love
I’ve given you too much but I’m takin’ back my love
I’m takin’ back my love, my love, my love, my love

Ooh, my love
(I’m taking back my love)
Ooh, my love

PS: Thanks Tien.

Dick Harrington was most recently the CEO and President of the world’s largest information media company Thomson Reuters and is largely recognized for his transformation of the company from a diversified holding company to the information services juggernaut it is today. He currently serves as my Partner and Chairman at our early-stage investment firm, Cue Ball. He and I recently had a conversation about the wisdom of applying big company lessons to small ones. Here are some highlights from that conversation:

After spending about a decade running a Fortune 500 – the world’s largest information media company – what motivates you to now work with early stage and small businesses?

Small businesses employ over half of all American private-sector employees and are responsible for most of the growth within the United States. Over the past decade, they have generated about 75 percent of new jobs annually. Most important, it is where our most creative thinking comes from. Still, most small companies fail because they have poor basic business practices. So I get excited about having the opportunity to mentor them and hopefully share some lessons. Think about it: it’s a lot more exciting to get a company from 0 to $100M than getting a billion dollar company its next $100M.

What is the biggest misconception people have between small and big businesses?

Most small businesses think that big companies have limitless resources and tons of money, and accordingly can do whatever they want. At the same time, most large companies think that all small ones are entrepreneurial, acting quickly, and bursting with creativity. Neither of these common beliefs is true. Most big companies do not throw a lot of resources at every project, and most small companies tend to become stagnant when they are through with their initial, entrepreneurial stage.

Give some examples of how you are applying big company lessons to the small firms you are investing in today.

The questions we asked ourselves while I was at Thomson are the same ones that every small business has to ask itself. At the end of the day, business is business. The size of the organization doesn’t matter. We all must understand our customers and the markets we serve, put the right people in the right places, and be sure the organization is aligned to deliver on our goals and objectives.

What strengths shold entrepreneurs focus on?

Small businesses have important competitive advantages. When founders are leading the company, they do so with an authentic passion to deliver on a vision. It’s their life. They know their business and customers better than anyone else, and this knowledge can be hugely leveraged with the right operational practices. A large company may have more money for research, but the leader of a small company almost always has more direct interaction with their customers. I am a huge believer that customer-driven strategies win over the long run.

What is the most significant challenge facing small businesses?

The biggest issue is how well the entrepreneur can scale. It’s important for entrepreneurs to realize that one person can’t control everything, that they can’t be VP of marketing, sales, operations, etc. That kind of mindset just won’t work in the long run.

How can an entrepreneur meet that challenge?

It’s important to let go – to trust people you hire – and to be okay with them making mistakes along the way. Even if a manager makes a decision 180 degrees in the wrong direction, it’ll probably be okay. Let them learn from their own mistakes.

What other lessons have you learned that would be helpful for small businesses and emerging leaders reading this?

Years ago I started a plumbing supply company with some partners. We did not have a lot of capital so we sometimes had to get creative on how we filled orders. We went out of our way to ensure that every order was filled, always. Sometimes, this meant getting the parts from competitors or buying at retail to complete the order. But that was okay. What mattered was never disappointing a customer. We had “Yes, we can” years before Obama did.

In addition to the customer-comes-first principle, I always had the motto that the higher you get in an organization, the harder you have to work. Success rarely happens on a nine-to five schedule. Also- dive into the important issues and from time to time “work the line” with other employees. The best way to shape people’s behavior is to inspire them by doing it yourself.

Finally, focus. Don’t sweat the small stuff. Save the intensity and for the most important company priorities and always make sure those are done first. To help make that happen, deal at most with five things at a time, and don’t put #6 on until #1 gets knocked off. You’ll definitely increase your chances for success.

General Info: About Gears

Gears is a plug-in that extends your browser to create a richer platform for web applications. For example, webmasters can use Gears on their websites to let users access information offline or provide you with content based on your geographical location. To install Gears, visit http://gears.google.com

Gears was designed to be used on both Google and non-Google sites. A number of web applications currently make use of Gears, including two Google products: Google Reader and Google Docs. Additionally, Zoho and Remember the Milk have been using Gears since its original launch. If you’re running Windows Mobile on your cellphone, Picasa Web Albums also makes use of Gears.

General Info: Where can I use Gears?

Gears works with a select group of sites that are specifically designed for compatibility. When you visit a site that’s configured to work with Gears, you should see a message stating “The website below wants to use Gears.” If you’d like to allow the use of Gears on this site, simply check the box next to “I trust this site. Allow it to use Gears.” and click the Allow button.

Note: Once you’ve allowed a site to use Gears, you won’t see this message again on that site
General Info: Offline data location

The operating system and the browser you’re using determine the location of your data. Below is a list of these locations:

Troubleshooting: Slow browser

Some sites may be slower when you activate Gears due to the syncing of your online and offline data. Once syncing is complete, the site should return to its normal speed.

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