Monday, August 6, 2007

Frameworks = components + patterns

Johnson, Ralph E
Communications of the ACM. Vol 40, (10) pp. 39 - 42

In order to understand frameworks you must first try and define them. We can define a framework in a computer sense as a reusable design of parts of a system represented by abstract classes. It provides a customizable interface for developers to use.
Frameworks are like components (such as those components in an OLE library) however they are more complex and also you can customise them allot further. A component can be thought as simply code reuse. A framework is more than that, it is actually design use as well.
Frameworks reuse design aspects like a template or a high level schema. The difference is that a framework has been described in a fixed programming language (Java or C++).
Reusing design has its benefits and its own cots. In the long run you can save time and money with Frameworks, however there is always the steep learning curve associated with developing it.
A pattern is a way to describe a solution to a problem in a certain context. Frameworks implement patterns in a specific way. That is they transform context specific ideas into some tangible code that solves a certain problem. For instance MVC is really a pattern, however the way Spring implements MVC can be though more as a framework.
Frameworks are in the middle between pure code reuse or design reuse. The allow us to use design principles and patterns in a language (and hence domain) specific way.

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