Model-view-controller (usually known as MVC) is a software design pattern commonly used for developing user interfaces which divides the related program logic into three interconnected elements. This is done to separate internal representations of information from the ways information is presented to and accepted from the user. This kind of pattern is used for designing the layout of the page.
In addition to dividing the application into these components, the model-view-controller design defines the interactions between them.
As with other software patterns, MVC expresses the "core of the solution" to a problem while allowing it to be adapted for each system. Particular MVC designs can vary significantly from the traditional description here.
One of the seminal insights in the early development of graphical user interfaces, MVC became one of the first approaches to describe and implement software constructs in terms of their responsibilities.
Trygve Reenskaug introduced MVC into Smalltalk-79 while visiting the Xerox Palo Alto Research Center (PARC) in the 1970s. In the 1980s, Jim Althoff and others implemented a version of MVC for the Smalltalk-80 class library. Only later did a 1988 article in The Journal of Object Technology (JOT) express MVC as a general concept.
The MVC pattern has subsequently evolved, giving rise to variants such as hierarchical model-view-controller (HMVC), model-view-adapter (MVA), model-view-presenter (MVP), model-view-viewmodel (MVVM), and others that adapted MVC to different contexts.
The use of the MVC pattern in web applications exploded in popularity after the introduction of NeXT's WebObjects in 1996, which was originally written in Objective-C (that borrowed heavily from Smalltalk) and helped enforce MVC principles. Later, the MVC pattern became popular with Java developers when WebObjects was ported to Java. Later frameworks for Java, such as Spring (released in October 2002), continued the strong bond between Java and MVC. The introduction of the frameworks Django (July 2005, for Python) and Rails (December 2005, for Ruby), both of which had a strong emphasis on rapid deployment, increased MVC's popularity outside the traditional enterprise environment in which it has long been popular. MVC web frameworks now hold large market-shares relative to non-MVC web toolkits.
Although originally developed for desktop computing, MVC has been widely adopted as a design for World Wide Web applications in major programming languages. Several web frameworks have been created that enforce the pattern. These software frameworks vary in their interpretations, mainly in the way that the MVC responsibilities are divided between the client and server.
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Because MVC decouples the various components of an application, developers are able to work in parallel on different components without affecting or blocking one another. For example, a team might divide their developers between the front-end and the back-end. The back-end developers can design the structure of the data and how the user interacts with it without requiring the user interface to be completed. Conversely, the front-end developers are able to design and test the layout of the application prior to the data structure being available.
The same (or similar) view for one application can be refactored for another application with different data because the view is simply handling how the data is being displayed to the user. Unfortunately this does not work when that code is also useful for handling user input. For example, DOM code (including the application's custom abstractions to it) is useful for both graphics display and user input. (Note that, despite the name Document Object Model, the DOM is actually not an MVC model, because it is the application's interface to the user).
To address these problems, MVC (and patterns like it) are often combined with a component architecture that provides a set of UI elements. Each UI element is a single higher-level component that combines the 3 required MVC components into a single package. By creating these higher-level components that are independent of each other, developers are able to reuse components quickly and easily in other applications.
The disadvantages of MVC can be generally categorized as overhead for incorrectly factored software.
More deeply, the framework exists to separate the representation of information from user interaction.