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Introduction

Behavioral design patterns focus on how objects collaborate, communicate, and interact to achieve a particular behavior in a system. They are like choreography instructions that define the steps and coordination among different components to accomplish a specific outcome in a software application.

Definition​

Behavioral design patterns deal with the assignment of responsibilities between objects, focusing on communication patterns and the delegation of tasks. They provide solutions for effectively organizing and coordinating the behavior of objects, enhancing the flexibility and understandability of the system. These patterns address the collaboration and communication aspects, allowing objects to work together seamlessly.

Considerations​

Considerations in behavioral design patterns involve carefully managing the interactions between objects to ensure that the responsibilities and behaviors are appropriately delegated. It's crucial to strike a balance between flexibility and complexity, promoting a design that is both maintainable and understandable.

Objectives​

Chain of Responsibility Pattern​

  • Objective:
    Pass a request through a chain of objects until it is handled.
  • Summary:
    The Chain of Responsibility Pattern allows a series of objects to handle a request, forming a chain. Each object in the chain decides whether to process the request or pass it along, providing a flexible way to handle requests without the sender knowing which object will ultimately handle it.

Command Pattern​

  • Objective:
    Turn a request into a standalone object, making it easy to parameterize clients with different requests, queue requests, and support undo operations.
  • Summary:
    The Command Pattern involves encapsulating a request as an object, allowing clients to parameterize with different requests, queue requests, and support undo operations. This decouples the sender and receiver of a request, providing flexibility in managing commands and their execution.

Iterator Pattern​

  • Objective:
    Access elements in a collection sequentially without exposing the underlying representation.
  • Summary:
    The Iterator Pattern provides a way to access elements in a collection sequentially without exposing the underlying representation of the collection. It involves separating the traversal of a collection from its structure, allowing for multiple ways to traverse the same collection.

Mediator Pattern​

  • Objective:
    Simplify interactions between different classes by introducing a mediator to coordinate communication.
  • Summary:
    The Mediator Pattern involves introducing a mediator object to simplify interactions between different classes. Instead of classes directly communicating with each other, they communicate through the mediator, promoting a more centralized and manageable system.

Memento Pattern​

  • Objective:
    Capture and externalize an object's internal state so the object can be restored to this state later.
  • Summary:
    The Memento Pattern involves capturing an object's internal state in a memento object, allowing the object to be restored to this state later. This pattern is particularly useful for implementing undo mechanisms or managing the state of an object.

Observer Pattern​

  • Objective:
    Establish a one-to-many dependency between objects, so when one object changes state, all its dependents are notified and updated automatically.
  • Summary:
    The Observer Pattern establishes a one-to-many dependency between objects, ensuring that when one object changes state, all its dependents are notified and updated automatically. It promotes loose coupling between objects, allowing for a flexible and extensible system.

State Pattern​

  • Objective:
    Allow an object to alter its behavior when its internal state changes, making the object appear to change its class.
  • Summary:
    The State Pattern allows an object to alter its behavior when its internal state changes, effectively making the object appear to change its class. It promotes encapsulation by representing different states as separate classes and delegating the state-specific behavior to these classes.

Strategy Pattern​

  • Objective:
    Define a family of algorithms, encapsulate each one, and make them interchangeable.
  • Summary:
    The Strategy Pattern involves defining a family of algorithms, encapsulating each one in a separate class, and making them interchangeable. This allows clients to choose the appropriate algorithm dynamically, promoting flexibility in selecting and switching algorithms.

Template Method Pattern​

  • Objective:
    Define the skeleton of an algorithm in the superclass but let subclasses override specific steps of the algorithm without changing its structure.
  • Summary:
    The Template Method Pattern defines the skeleton of an algorithm in the superclass, allowing subclasses to override specific steps without changing the algorithm's structure. It provides a way to enforce a common structure in a family of algorithms while allowing variations in certain steps.

Visitor Pattern​

  • Objective:
    Represent an operation to be performed on the elements of an object structure, allowing the definition of new operations without changing the objects.
  • Summary:
    The Visitor Pattern represents an operation to be performed on the elements of an object structure. It allows the definition of new operations without changing the classes of the objects being operated upon, promoting extensibility in handling diverse operations.