Description
Behavioral design patterns are concerned with algorithms and the assignment of responsibilities between objects.
Here is a list of behavioral design pattern types.
| Design Pattern | Description |
| Chain of Responsibility | Lets us pass requests along a chain of handlers. Upon receiving a request, each handler decides either to process the request or to pass it to the next handler in the chain. |
| Command | Turns a request into a stand-alone object that contains all information about the request. This transformation lets you pass requests as method arguments, delay or queue a request’s execution, and support undoable operations. |
| Iterator | Lets us traverse elements of a collection without exposing its underlying representation (list, stack, tree, etc.). |
| Mediator | Lets you reduce chaotic dependencies between objects. The pattern restricts direct communications between the objects and forces them to collaborate only via a mediator object. |
| Memento | Lets you save and restore the previous state of an object without revealing the details of its implementation. |
| Observer | Lets you define a subscription mechanism to notify multiple objects about any events that happen to the object they’re observing. |
| State | Lets an object alter its behavior when its internal state changes. It appears as if the object changed its class. |
| Strategy | Let you define a family of algorithms, puts each of them into a separate class, and make their objects interchangeable. |
| Template Method | Defines the skeleton of an algorithm in the superclass but lets subclasses override specific steps of the algorithm without changing its structure. |
| Visitor | Lets you separate algorithms from the objects on which they operate. |
Overall
We now know behavioral design patterns and their types.