Part 4: Behavioral Patterns

Behavioral patterns are mostly concerned with communication between objects. In Part IV, we examine the following.

The Chain of Responsibility allows a decoupling between objects by passing a request from one object to the next in a chain until the request is recognized.

The Command pattern utilizes simple objects to represent execution of software commands and allows you to support logging and undo operations.

The Interpreter pattern provides a definition of how to include language elements in a program.

The Iterator pattern formalizes the way we move through a list of data within a class.

The Mediator pattern defines how communication between objects can be simplified by using a separate object to keep all objects from having to know about each other.

The Memento pattern defines how you might save the contents of an instance of a class and restore it later.

The Observer pattern defines the way a number of objects can be notified of a change.

The State pattern allows an object to modify its behavior when its internal state changes.

The Strategy pattern encapsulates an algorithm inside a class.

The Template Method pattern provides an abstract definition of an algorithm.

The Visitor pattern adds polymorphic functions to a class noninvasively.