8 Types of Code Reuse

John Spacey, updated on May 23, 2017

Code reuse is the use of existing software to deliver functionality. Code is expensive and time consuming to develop and code reuse is considered a fundamental productivity strategy for information technology intensive businesses. The following are common types of code reuse.

Off The Shelf

Using commercial or non-commercial products that exist as opposed to reinventing them.

Extension

Extending your current systems, applications, services and libraries as opposed to doing something completely new.

Components

Designing systems and applications to maximize reuse by dividing functionality into useful components that hide complexity behind an interface.

Libraries

Packages of reusable components designed to be reused by multiple systems and applications.

Services

Wrapping reusable components in a service that can be deployed and operated separately from the rest of your systems and applications. Services reuse both the code and the operational aspects of a technology. For example, one team can operate a market data service for a bank as opposed to having 50 systems and applications that connect to market data feeds.

Platforms & Frameworks

Environments for developing functionality that may include a large number of APIs offered as libraries or services.

Cut & Paste

It is common for developers to copy code with which they are familiar and change it to be something new.

Forking

Officially taking code and changing it to be something new by creating a fork in a version control system. For example, a code base for a scientific calculator might be forked to create a financial calculator.

Overview: Code Reuse
Type	Coding
Definition	The use of existing software to deliver functionality.
Related Concepts	Layers Components APIs Libraries Microservices Software Design