Feature Architecture

The code is organised by features of the application

src/main/java
├── CommonClass.java
├── aDomain
│   ├── aDomainValueType.java
│   ├── aDomainEntity.java
│   ├── aDomainUseCase.java
│   ├── aDomainServlet
│   └── aDomainDatabaseAdapter.java
├── anotherDomain
│   ├── anotherDomainAudit.java
│   ├── anotherDomainValueType.java
│   ├── anotherDomainEntity.java
│   ├── anotherDomainConfiguration.java
│   ├── anotherDomainTemplate.vm
│   ├── anotherDomainRequestUnmarshaller.java
│   ├── anotherDomainResponseMarshaller.java
│   └── anotherDomainResponseTemplate.vm
└── CommonException.java

• No layers

• All code relating to the feature is under one package

  • Easy to find all code related to this domain/service

• Can split out code duplication into a separate package or library

  • ie http client/ gateway, crosscutting code, webserver setup, database setup etc

• Use of package private within each feature package

• It is screaming

• We have no package names to identify our adapters, and we still don’t see the incoming and outgoing ports.

• we cannot use package-private visibility to protect the domain code from accidental dependencies to persistence code.

• Since the infrastructure classes were in the same package and the core domain ones, it was hard to make sure that the dependencies pointed in the right direction.