This repository is home of the Aji Modeling Language (AjiL). AjiL is a modeling language with associated tools to support the developement of Microservice Architecture (MSA). If you want to know more about Model-Driven Engineering (MDE) I recommend the book Engineering Modeling Languages: Turning Domain Knowledge into Tools by Combemale et al.

As a modeling language, AjiL comprises three components: (i) Abstract syntax, (ii) Concrete syntax, and (iii) Semantics. Each component is described in the following.

Figure 1: AjiL Metamodel

As depicted in figure 1, starting from the system as the root element, a MSA consists of several microservices which can be classified as functional or their infrastructural purpose. Each service consists of a domain model, which aggregates multiple entities, and one or more interfaces. In AjiL, interfaces can provide abilities, e.g. create or read, to manipulate entities of a service and thus are used to describe the endpoint of a service. In addition to the multiplicities shown in the figure, the abstract syntax comes with several constraints, e.g. to conceal entity relations to a single service. The constraints form AjiL's syntactical semantics and are formulated in the Object Constraint Language (OCL). The constraints are detailed as follows.

• Unique names for the classes Microservice, Interface, Domain Model, Ability
• Unique ports for each service
• Entities are only allowed to inherit from Entities of the same Domain Model
• Entities are only allowed to relate to other Entities of the same Domain Model
• Prohibition of self-relations for Entities
• Functional services are not allowed to depend on themselfs

Figure 2: Notation Example

AjiL's concrete syntax, exemplified in figure 2, can be characterized as a Box-and-Line diagram type. It uses uses shapes and colors to distinguish between the different language elements.

To create and work with AjiL models to support MSA developement, the modeling language comes with an editor and a code generator.

For creating AjiL diagrams, AjiL comes with an editor which is realized using the Eclipse Sirius Framework.

At last, AjiL as a tool comprises a template-based generator realized with the Epsilon Generation Language (EGL). The generator is able to convert *.ajil model files to runnable microservices which rely on Spring Boot.

To use AjiL you need Eclipse Modeling Editon as IDE which directly includes the Epsilon and Sirius frameworks. AjiL was developed with Neon.1 but should also work with Oxygen.

To use the tools you need to import the sources as individual eclipse modeling projects and generate the necessary EMF projects with the genmodel mechanism in the ajil project. Here you are also able to change the metamodel (ecore file) with the included emf notation (ajil.emf).

To run the editor you need to execute the ajilGraphicalEditor.design project (Sirius Framework).

The generator is solely useable because the corresponding Aji ecore model is redundantly included. Therefore, if you change the metamodel, you need to change the ecore file in the generator project. The generator is currently hardcoded and therefore certain changes are needed to customize it to your needs. These changes can be done in AjilEglGenerator.java where the paths to the model and metamodel file need to be altered. Additionally, you need to change the target path in the main.egx file.

For any questions feel free to contact me here on github or visit Dortmund's University of Applied Sciences and Arts website.