Behavioral Patterns

Monitor Object

The Monitor Object pattern provides a mechanism to control access to a shared resource in a concurrent environment. It encapsulates the shared resource and its associated access methods, ensuring that only one thread can operate on the resource at any given time. This is achieved through the use of internal locking …

Template View

behavioral presentation

The Template View pattern separates the data from how it is presented to the user. It defines a template that outlines the structure of the view, and then concrete view classes fill in the data into the template. This allows for consistent presentation across different data sources or view variations, while still …

Transactional Outbox

behavioral integration reliability

The Transactional Outbox pattern solves the problem of reliably publishing events in a microservices architecture when an event needs to be triggered as a direct result of a database transaction. It ensures that events are not published if the transaction fails, maintaining data consistency. Instead of directly …

Branch by Abstraction

behavioral object-oriented

Branch by Abstraction decouples the logic that chooses which implementation to use from the implementations themselves. Instead of using conditional statements (if/else or switch) to select behavior based on type or configuration, it introduces an abstraction (interface or abstract class) and provides different …

Guarded Suspension

behavioral concurrency

The Guarded Suspension pattern addresses the problem of a thread needing to wait for a resource that isn’t immediately available. Instead of busy-waiting (repeatedly checking for availability), the requesting thread suspends itself, and a separate “guard” thread monitors the resource. When the …

Supervising Presenter

behavioral presentation

The Supervising Presenter pattern addresses the challenge of separating application logic from the user interface in a way that allows for testability and maintainability. It achieves this by introducing a Presenter that mediates between the Application (containing business logic) and the View (UI). The Presenter …

DSL

behavioral metaprogramming

A Domain-Specific Language (DSL) is a computer language specialized to a particular application domain. Unlike General-Purpose Languages (GPLs) like Java or Python, DSLs focus on solving problems in a specific area, offering a more concise and expressive way to represent solutions. By using terminology and constructs …

Reactor

behavioral concurrency

The Reactor pattern decouples event handling from the actual event sources. An event loop (“reactor”) monitors multiple event sources (like network sockets, timers, or user input) and dispatches events to associated handler functions when they occur. This allows for concurrent handling of multiple events within a …

Backend for Frontend

behavioral architectural

The Backend for Frontend (BFF) pattern addresses the complexities of building client applications that consume multiple backend services, particularly in microservice architectures. It involves creating a separate backend layer specifically tailored to the needs of each client type (e.g., web, mobile, smartwatch). …

Command

behavioral GOF

The Command pattern encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations. Essentially, it decouples the object that originates the request from the object that knows how to perform it.

This pattern promotes loose …