Building software using a microservice architecture is a means that gives more options to scale up applications, deploy them independently and limit their "blast radius" of failure. Microservices tend to solve the complexity and the increasing development problems by applying the functional decomposition principle. This main feature can become a point of weakness in the absence of a fully credible splitting mechanism. One of the main adopted approaches to design services and deal with the boundary identification concern is the Domain Driven Design (DDD). In this paper, we aim to study the efficiency of this approach. We intend to give software architects a full understanding of its capabilities and main limits to be aware of the potential resulting anti-patterns. To this end, we use graph theory to experiment and analyze a reference example, implementing many microservices good practices and patterns. The obtained results show whether if we can rely only on the DDD principles to decompose microservices, or not.

Materialization is a powerful and ubiquitous abstraction pattern for conceptual modeling that relates a class of categories (e.g., models of cars) and a class of more concrete objects (e.g., individual cars). This paper presents materialization as a generic relationship between two classes of objects and describes an abstract implementation of it. The presentation is abstract in that it is not targeted at a specific object system. The target system is supposed to provide: 1) basic object-modeling facilities, supplemented with an explicit metaclass concept and 2) operations for dynamic schema evolution like creation or deletion of a subclass of a given class and modification of the type of an attribute of a class. The presentation is generic in that the semantics of materialization is implemented in a metaclass, which is a template to be instantiated in applications. Application classes are created as instances of the metaclass and they are thereby endowed with structure and behavior consistent with the generic semantics of materialization.