2

first of all: I'm new to the EMF world. I worked through the Book "Model driven software engineering in practice" and now I want to apply this in a project:

I "meta modelled" my Project and implemented some OCL Constraints, which is therefore like a semantic database schema.

  1. What i don't understand is, how i implement the business logic? Is this just possible with OCL Constraints and Model transformations? It would be very overengineered if i would implement everything with henshin.

  2. i want to use my model as a "backend". that the client can access some parts of the model via REST. What possibities do I have to make it happen?

Thank you, Laurens

Jordi Cabot
  • 8,058
  • 2
  • 33
  • 39
Laureeens
  • 23
  • 5

3 Answers3

2

If you are using EMF, you probably want to use Eclipse OCL or Dresden OCL.

(As the primary Eclipse OCL author I can answer for Eclipse OCL. Perhaps a Dresden OCL author may give you an alternative answer.)

Eclipse OCL provides an Xtext-based OCLinEcore editor that allows you to embed your OCL as EAnnotations within your Ecore model, thereby implementing your business logic. You may also choose to have your embedded OCL genmodelled as direct Java code rather than interpreted OCL. See the OCL tutorials in the OCL documentation accompanying the Eclipse OCL distribution.

Alternatively you may use the Xtext-based Complete OCL editor to maintain your OCL as a complementing document for your metamodel. There is currently no direct Java code generation for this approach and you need to arrange to import the Complete OCL document into your consuming application.

I an enthusiastic supporter of M2M so I would recommend using an M2M, Henshin if that is your favourite, to define your transformations resorting only to OCL or Java to flesh out some per-class queries. EMF provides a nice isolation so that EMF applications can be substantially ignorant of the technologies used to implement EOperations.

Ed Willink
  • 1,205
  • 7
  • 8
  • Thank you very much. I already made some OCL Constraints, but I want to use EMF to make it possible for domain experts to put in data via the Model Generator. But simultaneously, i want to have parts of the model accessible for an mobile app. Therefore i think it is better to go more "platform specific". How can I realize a backend? - i have to add a databse. - But how can i realize Methods? - add a REST interface – Laureeens Mar 28 '18 at 14:00
  • Sorry. Your words make sense but the sentences do not. I am lost. – Ed Willink Mar 28 '18 at 19:43
1

You may want to take a look at our EMF Rest tool https://som-research.uoc.edu/tools/emf-rest/

We have not been updated it in a while but it could be used as an example of what you could build

Jordi Cabot
  • 8,058
  • 2
  • 33
  • 39
0

As already mentioned there OCLinEcore which is Xtext based. Xtext does now fully support the Language Server Protocol, which means you can keep your model on a server and interact with it either via REST, Json-RPC or even websockets. The guys from xtext recently came up with Sprotty, which is a

web based, diagramming framework

This might be interesting for you, because it demonstrates how to use a model server. Here are also some slides about sprotty and also the Xtext LSP Architecture. Sprotty is targeted towards diagramming support in the browser, but I think the server architecture might get you started, even if you don't need a front end or an editor.

Mad Matts
  • 1,118
  • 10
  • 14
  • This is very interesting and , but for now it is a little bit overengineered. But i want parts of the model just be manipulated via REST how can i make it possible? – Laureeens Mar 28 '18 at 13:56
  • Well you obviously need a server listening for requests and then you can perform some operations on your model stored on the server. I can recommend [jetty](http://www.eclipse.org/jetty/documentation/current/advanced-embedding.html#jetty-helloworld) as your server framework, since it's easy to set up, but you can choose as you like. – Mad Matts Mar 28 '18 at 17:49
  • "OCLinEcore is Xtext-based" and "Xtext-based is LSP supported" implies "OCLinEcore is LSP supported" would be nice, but in my experience there are always SNAFUs.As the OCLinEcore developer I know that some corners of Xtext are exploited/replaced. I have no idea what is involved in LSP support. If someone can point me at a simple LSP for Xtext editors guide, I might be able to eliminate some of the SNAFUs. – Ed Willink Mar 28 '18 at 19:50