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*[[phpXCore]] A MVC design pattern based PHP content management framework compatible with PHP4 and PHP5.
*[[phpXCore]] A MVC design pattern based PHP content management framework compatible with PHP4 and PHP5.
*[[PRADO]] A PHP 5 MVC framework modeled after [[ASP.NET]] web forms.
*[[PRADO]] A PHP 5 MVC framework modeled after [[ASP.NET]] web forms.
*[[PureMVC]] Framework for PHP
*[[Qcodo]] is an open-source PHP 5 web application framework
*[[Qcodo]] is an open-source PHP 5 web application framework
*[[SilverStripe]] contains a fully fledged PHP 5.2 ORM/MVC Framework focused on building websites. Much like [[Ruby on Rails]].
*[[SilverStripe]] contains a fully fledged PHP 5.2 ORM/MVC Framework focused on building websites. Much like [[Ruby on Rails]].

Revision as of 23:25, 24 November 2008

A simple diagram depicting the relationship between the Model, View, and Controller. Note: the solid lines indicate a direct association, and the dashed lines indicate an indirect association (e.g., observer pattern).

Model-view-controller (MVC) is both a design pattern and an architectural pattern used in software engineering. Successful use of the pattern isolates business logic from user interface considerations, resulting in an application where it is easier to modify either the visual appearance of the application or the underlying business rules without affecting the other. In MVC, the model represents the information (the data) of the application and the business rules used to manipulate the data; the view corresponds to elements of the user interface such as text, checkbox items, and so forth; and the controller manages details involving the communication to the model of user actions such as keystrokes and mouse movements.

History

The pattern was first described in 1979[1] by Trygve Reenskaug, then working on Smalltalk at Xerox PARC. The original implementation is described in depth in the influential paper Applications Programming in Smalltalk-80: How to use Model-View-Controller.[2]

After that, numerous derivatives of the MVC pattern appeared. Probably one of the most known of them is the Model View Presenter pattern, which appeared in the early 90s and was designed to be an evolution of MVC. However Model-View-Controller still remains very widely used.

In November of 2002 the W3C voted to make MVC structures part of their XForms architecture for all future web applications [3] . These specifications will now be integrated directly into the XHTML 2.0 specifications. There are now over 20 vendors that support XForms frameworks with MVC integrated into the application stack.

Pattern description

Model-view-controller is both an architectural pattern and a design pattern, depending on where it is used.

As an architectural pattern

It is common to split an application into separate layers that run on different computers: presentation (UI), domain logic, and data access. In MVC the presentation layer is further separated into view and controller.

MVC is often seen in web applications, where the view is the actual HTML page, and the controller is the code that gathers dynamic data and generates the content within the HTML. Finally, the model is represented by the actual content, usually stored in a database or in XML nodes, and the business rules that transform that content based on user actions.

Though MVC comes in different flavors, control flow generally works as follows:

  1. The user interacts with the user interface in some way (e.g. presses a button).
  2. A controller handles the input event from the user interface, often via a registered handler or callback.
  3. The controller notifies the model of the user action, possibly resulting in a change in the model's state. (e.g. controller updates user's Shopping cart).[4]
  4. A view uses the model (indirectly) to generate an appropriate user interface (e.g. the view produces a screen listing the shopping cart contents). The view gets its own data from the model. The model has no direct knowledge of the view.
  5. The user interface waits for further user interactions, which begins then a new cycle.

Some implementations such as the W3C XForms also use the concept of a dependency graph to automate the updating of views when data in the model changes.

By decoupling models and views, MVC helps to reduce the complexity in architectural design, and to increase flexibility and reuse.

As a design pattern

MVC encompasses more of the architecture of an application than is typical for a design pattern.

Model
The domain-specific representation of the information on which the application operates. Domain logic adds meaning to raw data (e.g., calculating whether today is the user's birthday, or the totals, taxes, and shipping charges for shopping cart items).
Many applications use a persistent storage mechanism (such as a database) to store data. MVC does not specifically mention the data access layer because it is understood to be underneath or encapsulated by the Model.
View
Renders the model into a form suitable for interaction, typically a user interface element. Multiple views can exist for a single model for different purposes.
Controller
Processes and responds to events, typically user actions, and may invoke changes on the model.

Selected frameworks

GUI frameworks

Java: Java Swing

Java Swing is different from the other frameworks, in that it supports two MVC patterns:

Model

Frame level model-- Like other frameworks, the design of the real model is usually left to the developer.
Control level model-- Swing also supports models on the level of controls (elements of the graphical user interface). Unlike other frameworks, Swing exposes the internal storage of each control as a model.
View
The view is represented by a class that inherits from Component.
Controller
Java Swing doesn't necessarily use a single controller. Because its event model is based on interfaces, it is common to create an anonymous action class for each event. In fact, the real controller is in a separate thread (the Event dispatching thread). It catches and propagates the events to the view and model.

Combined frameworks

Java: Java Enterprise Edition (Java EE)

Simple Version using just Servlets and JSPs from J2EE:

Model
The model is a collection of java classes that together do something useful - they make up a software application which might involve moving data around. There is a single front end class that can communicate with any UI - eg a console, a thick GUI or a web application.
View
The view is represented by Java Server Page, with data being transported to the page in the HttpServletRequest or HttpSession.
Controller
The controller servlet communicates with the front end of the model and loads the HttpServletRequest or HttpSession with appropriate data, before forwarding the HttpServletRequest and Response to the JSP using a RequestDispatcher.

The simple version uses the best parts of Servlet and JSP technology: the servlet is essentially a Java class and communicates and interacts with the model but does not have to do extensive generation of xhtml output; the JSPs do not have to communicate with the model as they are provided with the information they need by the servlet - they can concentrate on creating xhtml output.

Unlike the other frameworks, Java EE defines a pattern for model objects.

Model
The model is commonly represented by entity beans, although the model can be created by a servlet using a business object framework such as Spring.
View
The view in a Java EE application may be represented by a Java Server Page, which may be currently implemented using JavaServer Faces Technology (JSF). Alternatively, the code to generate the view may be part of a servlet.
Controller
The controller in a Java EE application may be represented by a servlet, which may be currently implemented using JavaServer Faces (JSF).

XForms

XForms is an XML format for the specification of a data processing model for XML data and user interface(s) for the XML data, such as web forms.

Model

XForms stores the Model as XML elements in the browser. They are usually placed in the non-visible <head> elements of a web page.

View

The Views are XForms controls for screen elements and can be placed directly in the visible section of web page. They are usually places in the <body> elements of a web page.

The model and views are bound together using reference or binding statements. These binding statements are used by the XForms dependency graph to ensure that the correct views are updated when data in the model changes. This means that forms developers do not need to be able to understand either the push or pull models of even processing.

Controller

All mouse events are processed by XForms controls and XML events are dispatched.

Implementations of MVC as GUI frameworks

Smalltalk's MVC implementation inspired many other GUI frameworks, such as the following:

Implementations of MVC as web-based frameworks

In the design of web applications, MVC is implemented by web template systems as "View for web" component.

MVC is typically implemented as a "Model 2" architecture in Sun parlance. Model2 focuses on efficiently handling and dispatching full page form posts and reconstructing the full page via a front controller. Complex web applications continue to be more difficult to design than traditional applications because of this "full page" effect. More recently AJAX driven frameworks that focus on firing focused UI events at specific UI Components on the page are emerging. This is causing MVC to be revisited for web application development using traditional desktop programming techniques.

.NET

ColdFusion

  • Mach-II A framework that focuses on trying to ease software development and maintenance
  • Model-Glue Through a simple implementation of Implicit Invocation and Model-View-Controller, they allow applications to be well organized without sacrificing flexibility.
  • FuseBox Fusebox does not force the Model-View-Controller (MVC) pattern or Object-Oriented Programming (OOP) on the developer. However, either or both of these development approaches can be used with Fusebox.
  • PureMVC Framework for ColdFusion

Java

MVC web application frameworks:

JavaScript

MVC web application frameworks:

  • SproutCore
  • Wavemaker WYSIWYG development platform for Ajax web applications[5]
  • DojoMVC JavaScript MVC based upon Dojo core. Includes jQuery integration.

ABAP Objects

Informix 4GL

  • Informix 4GL MVC models to use for Informix 4GL report and form creation
  • EGL — IBM's EGL MVC Implementation

Perl

PHP

  • Akelos PHP Framework a Ruby on Rails port to PHP4/5.
  • barebonesmvc A one-file, no-configuration, PHP 5 MVC framework.
  • CakePHP webapplication framework modeled after the concepts of Ruby on Rails.
  • CodeIgniter A PHP MVC framework.
  • ash.MVC A Simple MVC Framework with PHP.
  • FUSE A powerful but easy-to-use PHP 5 Framework for MVC development modeled after the concepts of Ruby on Rails.
  • ELF PHP ELF PHP is a php framework with a very small footprint, built on Model-View-Controller architecture.
  • Jelix Framework an open source PHP 5 MVC framework designed for highly performance.
  • Joomla v1.5.x is an open source Content Management System that employs the MVC model for its extensions, called components and modules.
  • KISSMVC Feather-weight, procedural PHP MVC Framework designed based on the KISS Principle.
  • KohanaPHP A powerful, lightweight, easily extendable PHP 5 MVC Framework.
  • Konstrukt A PHP MVC / RESTful framework
  • LightVC Lightweight PHP 5 Strict MVC Framework with decoupling of Model and other non-View-Controller essentials to promote code reuse.
  • LISA MVC Lisa is an OOP MVC web application framework based on PHP 5.2 and Smarty template engine.
  • Odin Assemble Small footprint PHP based MVC Framework.
  • Orinoco Framework is a full-stack yet lightweight framework written in PHP5. It implements the Model 2 design paradigm.
  • PHPDevShell A flexible GUI ready administrator application development framework.
  • phpXCore A MVC design pattern based PHP content management framework compatible with PHP4 and PHP5.
  • PRADO A PHP 5 MVC framework modeled after ASP.NET web forms.
  • PureMVC Framework for PHP
  • Qcodo is an open-source PHP 5 web application framework
  • SilverStripe contains a fully fledged PHP 5.2 ORM/MVC Framework focused on building websites. Much like Ruby on Rails.
  • Solar
  • Switch board (framework) with Routing PHP 5 MVC Framework with Routing.
  • SWiZ A PHP 5 framework based on MVC paradigm and component model, emphasizing reusability, clean OPP design and flexibility.
  • Symfony Framework PHP 5 MVC Framework modeled after the concepts of Ruby on Rails.
  • XPT Framework A PHP 5 MVC framework.
  • Zend Framework A PHP 5-based MVC framework modeled after the concepts of Ruby on Rails.
  • ZNF PHP5 MVC framework for enterprise web applications
  • Zoop Framework A Mature PHP 4/5 MVC framework.
  • Zigmoyd PHP 4/5 MVC Framework

Python

  • Django A complete Python web application framework. Django prefers to call its MVC implementation MTV, for Model-Template-View.
  • ETS- Enthought Tool Suite The Enthought Tool Suite brings the Model-view-controller mindset to scientific GUI's and visualization
  • Pylons - Python Web Framework
  • TurboGears for Python
  • web2py A scalable full-stack enterprise level Python agile web development framework with support for highly flexible and rapid database-driven web application development.
  • Zope Content Management Framework

Ruby

Smalltalk

XML

  • XForms - XForms has an integrated Model-view controller architecture with an integral dependency graph that frees the programmer from specifically having to perform either push or pull operations.

See also

References

  1. ^ http://heim.ifi.uio.no/~trygver/themes/mvc/mvc-index.html
  2. ^ How to use Model-View-Controller (MVC)
  3. ^ Dubinko, Micah (2004-11-12). "XForms 1.0 Basic Profile". Retrieved 2008-10-16. {{cite web}}: Check date values in: |date= (help)
  4. ^ Complex controllers are often structured using the command pattern to encapsulate actions and simplify extension.
  5. ^ "Product Review: WaveMaker's point-and-click Java". Infoworld. April 24, 2008. Retrieved 2008-04-25.

General information regarding MVC

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