In software engineering, behavioral design patterns are design patterns that identify common communication patterns among objects. By doing so, these patterns increase flexibility in carrying out communication.

Examples of this type of design pattern include:

Blackboard design pattern

Provides a computational framework for the design and implementation of systems that integrate large and diverse specialized modules, and implement complex, non-deterministic control strategies

Chain-of-responsibility pattern

Command objects are handled or passed on to other objects by logic-containing processing objects

Command pattern

Command objects encapsulate an action and its parameters

"Externalize the stack"

Turn a recursive function into an iterative function that uses a stack^[1]

Interpreter pattern

Implement a specialized computer language to rapidly solve a specific set of problems

Iterator pattern

Iterators are used to access the elements of an aggregate object sequentially without exposing its underlying representation

Mediator pattern

Provides a unified interface to a set of interfaces in a subsystem

Memento pattern

Provides the ability to restore an object to its previous state (rollback)

Null object pattern

Designed to act as a default value of an object

Observer pattern

a.k.a. Publish/Subscribe or Event Listener. Objects register to observe an event that may be raised by another object

Weak reference pattern

De-couple an observer from an observable^[2]

Protocol stack

Communications are handled by multiple layers, which form an encapsulation hierarchy^[3]

Scheduled-task pattern

A task is scheduled to be performed at a particular interval or clock time (used in real-time computing)

Single-serving visitor pattern

Optimise the implementation of a visitor that is allocated, used only once, and then deleted

Specification pattern

Recombinable business logic in a boolean fashion

State pattern

A clean way for an object to partially change its type at runtime

Strategy pattern

Algorithms can be selected on the fly, using composition

Template method pattern

Describes the skeleton of a program; algorithms can be selected on the fly, using inheritance

Visitor pattern

A way to separate an algorithm from an object

• Concurrency pattern
• Creational pattern
• Structural pattern