Behavioral Patterns

Last Updated: Dec 7, 2024

Behavioral patterns focus on communication and responsibilities between objects, making interactions more flexible and organized.

WARNING

I am only listing the ones that I've been dealing with or interact with a couple of times 😃

TL;DR

• Observer: Notifies multiple objects of state changes in a central object, great for event-driven systems.
• State: Allows an object’s behavior to change based on its internal state.
• Template Method: Defines a skeleton of an algorithm, allowing subclasses to customize parts of it.

Observer Pattern

Definition

The Observer Pattern establishes a one-to-many dependency between objects, so that when one object changes state, all its dependents are notified and updated automatically.

• Subject is an object that maintains a list of observers and notifies them of state changes.
• Observers are objects that subscribe to the subject to receive updates.

Flow

• State Change: The Subject's state changes (e.g., data is updated).
• Notification: The Subject notifies all registered Observers of the change.
• Observer Reaction: Each Observer reacts to the notification, which may involve updating the UI or performing some other action.

State Pattern

Definition

The State Pattern establishes a one-to-many dependency between objects, so that when one object changes state, all its dependents are notified and updated automatically.

• Subject is an object that maintains a list of observers and notifies them of state changes.
• Observers are objects that subscribe to the subject to receive updates.

Flow

• State Change: The Subject's state changes (e.g., data is updated).
• Notification: The Subject notifies all registered Observers of the change.
• Observer Reaction: Each Observer reacts to the notification, which may involve updating the UI or performing some other action.

Template Method Pattern

Definition

The Template Method Pattern establishes a one-to-many dependency between objects, so that when one object changes state, all its dependents are notified and updated automatically.

• Subject is an object that maintains a list of observers and notifies them of state changes.
• Observers are objects that subscribe to the subject to receive updates.

Flow

• State Change: The Subject's state changes (e.g., data is updated).
• Notification: The Subject notifies all registered Observers of the change.
• Observer Reaction: Each Observer reacts to the notification, which may involve updating the UI or performing some other action.