This post is about the value object pattern and the factory pattern which are tactical patterns in domain driven design (DDD). Value objects define the second kind of domain objects besides entities. Their main characteristic is immutability: Attributes of a…
Continuing the series about modularization patterns with Java 9 today I would like to introduce the patterns Default Implementation and Module Facade [Kno12]. As its name suggests, the Default Implementation pattern is about providing implementations for abstract modules but also…
In this post, we look at two usability patterns: Published Interface and External Configuration. Usability patterns help to integrate modules with each other and generally simplify development with modules. When working with a module, the developer needs to know how…
The next pattern that I would like to discuss is called “Independent Deployment” [Kno12]. It states that modules should be independently deployable units. For a module to be independently deployable, it cannot have any outgoing dependencies on other modules. In…
While developing software in Java and other languages, we often create abstractions and separate them from the implementation. This practice has many benefits that we would like to take advantage of while designing modules. The Abstract Module and Separate Abstraction…
Modularization is the process of organizing code into cohesive units. This process is sometimes tedious and hard to do consistently. Patterns can help to make modularization simpler by providing solutions for some common problems. [Kno12] and [Sand&Bak17] are two books…
With version 9 of Java, a new module system is introduced into the language. This module system is used internally for the JDK libraries but can be used by the application code as well. In contrast to other module systems…