Duck typing

In computer programming with object-oriented programming languages, duck typing is a style of dynamic typing in which an object's current set of methods and properties determines the valid semantics[n. 语义学], rather than its inheritance from a particular class or implementation of a specific interface.

The name of the concept refers to the duck test, attributed to James Whitcomb Riley , which may be phrased as follows:

When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.

 

http://en.wikipedia.org/wiki/Duck_typing