Cocoa is Apple's native object-oriented application programming interface (API). Earlier, this program environment was constructed for Mac OS X operating system. However, the Cocoa originates from the neXTSTEP and OpenStep programming environments which afterward became Apple's property, after they get the company neXT. Now, all iPhone applications are developed within this framework. Not only, iPhone, applications for the iPod Touch and the iPad, are also developed using Cocoa. It consists of the Foundation Kit, Application Kit, and Core Data frameworks.
Frameworks of Cocoa:
Cocoa consists of 3 'Objective-C' object libraries called frameworks. These are similar to shared libraries in functionality. Frameworks' add associated resources, header files, and documentation to the framework. The Cocoa frameworks are implemented as a type of application bundle, containing the below mentioned items in standard locations.
• Foundation Kit
• Application Kit or AppKit
• Core Data
A key part of the Cocoa architecture is its comprehensive view model, which allows creation of custom drawing content in cocoa framework, using PostScript-like drawing commands. This in-turn allows automatic printer support and so forth. Cocoa framework manages all the clipping, scrolling, scaling and other chores of drawing graphics, thus the programmer is freed from implementing basic infrastructure and he/she only needs to concentrate on the unique aspects of an application's content.