Domain-Driven Design (DDD)¶

Category: Architecture Tags: ddd, java, design, microservices, kubernetes

Overview¶

Domain-Driven Design (DDD) is an approach to software development that focuses on modeling software based on the business domain, using rich, behavior-focused models.

What It Is¶

Uses bounded contexts to divide complex systems
Rich domain models with entities, value objects, and aggregates
Collaboration between developers and domain experts

Why Use It¶

Aligns code with real business logic
Helps manage complexity
Encourages strategic design decisions

When To Use It¶

Complex business domains
Multiple subdomains and teams
Systems needing long-term evolution

Implementation Examples¶

Code Example (Java Domain Model)¶

public class Invoice {
    private List<LineItem> items;

    public BigDecimal getTotal() {
        return items.stream().map(LineItem::getAmount).reduce(BigDecimal.ZERO, BigDecimal::add);
    }
}

Infra Tip (Kubernetes)¶

Use namespaces or Helm charts to separate bounded contexts in microservices deployments.

Key Concepts Summary¶

Focus on business logic and models
Uses Ubiquitous Language between tech and business
Breaks systems into bounded contexts

Best Practices / Tips¶

Work closely with domain experts
Use layered architecture within each bounded context
Combine with event-driven or microservices architecture

Common Issues / Troubleshooting¶

Problem 1: Overengineering¶

Cause: DDD applied to simple domains
Solution: Use tactical patterns only where needed

Problem 2: Poor context boundaries¶

Cause: Miscommunication or unclear scope
Solution: Use Event Storming to clarify models

References / Further Reading¶

https://domainlanguage.com/ddd/
https://www.dddcommunity.org/