Behavioral patterns

Behavioral design patterns are concerned with the interaction and responsibility of objects.

pattern	description
Chain of responsibility	Sends a request to a chain of objects. Thus, a request can be handled by one or more objects.
Command	Provides the command objects that decide who can handle command.
Interpreter	Provides a way to evaluate language grammar or expression.
Iterator	Represents iterator to traverse a container and access the container's elements.
Mediator	Provides an object that encapsulates how a set of objects interact.
Memento	Provides the ability to restore the object's previous state.
Observer	Notifies clients that state of object was changed.
Strategy	Allows to select an algorithm at runtime.
Visitor	Allows you to perform operation on group of objects. Algorithm of operation independent from structure of that group.
Null object	Implements the expected interface where methods do nothing.