Wrapper

From DmWiki

A wrapper is a piece of code which allows you to better interact with an existing piece of code - it wraps this piece of code. For instance, one might have a music player that attempts to play any URL it is given, and a game engine that uses strings to refer to file resources. A useful wrapper would be one that wraps the music player so that it takes a filename string and converts it to an URL which it then plays. Working in the other direction, if the music player encountered an error the wrapper could reset the player to make it recover from the error and write the error to the game engine's error log file.

A frequent use of wrappers is to make an engine API-independent, by creating a wrapper that allows one to switch between OpenGL and Direct3D without changing high-level code. Another place for a wrapper might be in networking, where a wrapper over the WinSock library can be handy.

Basically a wrapper is a way to abstract to a higher level; it can be to simplify (grouping many tasks) or to achieve language and/or API independence.