Patterns

Scheduler-Agent-Supervisor

behavioral concurrency distributed systems

The Scheduler-Agent-Supervisor pattern addresses the challenge of reliably executing tasks in a distributed or concurrent environment. A Scheduler is responsible for creating and assigning tasks to Agents. Agents execute these tasks and report their status. A Supervisor independently monitors the Agents and, if an …

Rate Limiting

behavioral resilience microservices

Rate limiting is a technique used to control the rate at which users or systems can access a resource. This is crucial for preventing abuse, ensuring service availability, and protecting backend systems from overload. By limiting the number of requests within a specific timeframe, rate limiting helps to maintain a …

Cache Aside

behavioral performance

The Cache Aside pattern is a caching technique where the application first checks if the requested data exists in the cache. If it does, the cache returns the data immediately. If the data is not in the cache (a “cache miss”), the application retrieves it from the database, stores a copy in the cache for …

Monitor Object

concurrency behavioral

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 …

Redux

architectural state management functional

Redux is a predictable state container for JavaScript apps. It helps you manage your application’s state in a centralized and organized manner, making it easier to debug, test, and reason about your application’s behavior. The core idea is to keep the application’s state in a single, immutable store, and only …

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 …