Behavioral Patterns

Aggregate

The Aggregate pattern is a core concept in Domain-Driven Design (DDD). It defines a cluster of domain objects (Entities and Value Objects) that are treated as a single unit. This unit is responsible for maintaining data consistency within its boundaries and presenting a cohesive interface to the outside world. An …

Circuit Breaker

behavioral resilience

The Circuit Breaker pattern protects a system from repeated failures of a dependent service. It monitors calls to the dependency and, upon observing a certain failure rate, “opens the circuit” to prevent further requests from being sent. This allows the dependent service to recover without being …

Content-Based Router

behavioral integration

The Content-Based Router pattern dynamically routes messages to different recipients or endpoints based on the content of the message itself. Unlike address-based routing which uses a header field to determine the destination, content-based routing examines the message body, properties, or payload to make a routing …

Fail Fast

behavioral robustness

The Fail Fast pattern is a strategy for dealing with errors as quickly as possible. Instead of attempting to continue execution after detecting a problem, the system immediately halts and reports the error. This minimizes the potential for cascading failures, reduces debugging time, and makes error handling more …

Saga (Choreography)

behavioral distributed systems DDD

The Saga pattern is a distributed transaction management pattern for coordinating a sequence of local transactions across multiple microservices. Unlike traditional distributed transactions (like two-phase commit), Sagas don’t rely on centralized locking or coordination. Instead, each local transaction updates …

Write-Behind Cache

behavioral performance

The Write-Behind Cache pattern improves performance by allowing operations that modify data to complete quickly, without the latency associated with directly updating persistent storage. Instead of synchronously writing to the database or file system, modifications are first applied to the cache, and a background …

Observer

GOF behavioral

Oberver Pattern enables the broadcast communication between an event subject, that emits changes to its state to all of its observers.

Usage

Modern day usage is biased by the existence of rx and the reactive libraries across most important languages. Most modern libraries rely on observables and observers to get the …