Is there a recognized pattern for useless objects that implement an interface?

Question

For example, (although it's not an interface) the Stream class in .NET has an implementation provided by Stream.Null which simply discards the data. PowerShell has Out-Null.

In applications I've developed, I've often found it useful to implement an interface IFoo with a default implementation NullFoo or similar when it is preferable to have a useless implementation rather than not passing an object at all.

My question is how should I refer to this practice in documenting or explaining an architecture? Is there a recognized name or GoF/Fowler design pattern for this?

Answer 1

This pattern is often refered as "NullObject" : http://en.wikipedia.org/wiki/Null_Object_pattern