Tools for Diagrammatic Specifications

Stian SkjerveggenSupervisors: Yngve Lamo, Adrian Rutle, Uwe Egbert

Wolter

The background

Formal models can be expressed by specification techniques specified in Diagrammatic Predicate Logic (DPL)

DPL is a proposed formalism for Model-Driven Software Architecture

Our focus is on investigating, adapting, evaluating… these proposals

Todays situation

Many different editors for modeling languages exists

The main problem is that they have no generic way to describe modeling languages

… and most of them have semi-formal semantics

The project

A graphical editor is to be designed and implemented that allows to specify abstract signatures corresponding to metamodels of modeling languages and also supports the definition of transformations between those signatures.

Slogan: Signature ~ Modeling Language

Related work

Sketcher95• Incomplete

• Not fully functional

• No source code

Sketcher v1.0 (.NET)• Previous master thesis

• Also incomplete and not fully functional

• Tries to recreate Sketcher95

The platform

Previous version in C # Eclipse was chosen as the developing platform So why choose Eclipse?

• Alot of model related projects in the Eclipse community (Eclipse Modeling Framework)

• You get a lot for free by using Eclispe

Eclipse is much more than just a Java IDE Eclipse can be used to create many different

types of applications

What Eclipse provides

Open source, robust, commercial quality platform

Extensible frameworks For this project, the main features are

the Eclipse Modeling Framework, the Graphical Editing Framework and the Graphical Modeling Framework

Eclipse Modeling Framework - EMF

A modeling framework and code generation facility

Model specification described in XMI XMI (XML Metadata Interchange) is

OMGs standard for exchanging Metadata information

The core of EMF is called Ecore (metamodel of EMF models is Ecore)

The advantages of EMF

Serialization Notification Code generation

Low cost entry for/into modeling

Graphical Editing Framework

Allows developers to take an existing application model and quickly create a rich graphical editor

Many common operations are provided MVC architecture

The advantages of GEF

Most of the graphical elements are predefined and can be extended

A standard look and feel for all graphical editors in Eclipse

Graphical Modeling Framework - GMF

GMF bridges the gap between the model (EMF), the view and the controller (both from GEF)

With GMF you can produce graphical editors for Eclipse

GMF Workflow

Generator Model (GMFGen)

Java code

Mapping (GMFMap)

Tool Definition (GMFTool)

Graphical Definition (GMFGraph)

Domain Model (ECore)

Example GMF application

Drawing palette

View

<eClassifier eType=”EClass” name=”Supplier”><eStructuralFeature eType=”eReference” name=”orders”

eReferenceType=”PurchaseOrder”/> …</eClassifier>

Domain Model

Summary of the frameworks used

EMF provides the model and serialization of it

GEF provides the visualization and the controllers

GMF maps the model, controllers, the visualization and tools (drawing palette) together and generates a diagram editor

Challenges

The biggest challenge is finding out how to do things in Eclipse

Eclipse is a prime example of Agile Development

Eclipse UI Guideline Eclipse Best Practices ”Ready for Rational Software” -- IBM

Challenges EMF

Need additional info for our model EMF supports Extended Meta Data and

this gets recorded as annotations in the Ecore model

Challenges GMF

The code that GMF generates must often be adapted

A lot of code has to be customized to support our additional information

GMF generated code

For a simple diagram containing only Nodes and Edges, 90 source files are generated, with most of the classes extending other classes

Modeling and DPL formalism

Signatures ~ Modeling languages Signature := collection of predicates Predicate ~ constraints set by modeling

languages Diagram Specifications ~ models

Predicates

You can compare a predicate to a Design Pattern

Want to label elements (nodes, arrows and diagrams) from the model by one or more predicates

This must be visualized somehow (next) The predicate information needs to be

saved with the model

How are Predicates Visualized?

Predicates on arrows Arrow decorations

Predicates on nodes Node decorations

Predicates on diagrams Diagram decorations• Diagram dec. := decoration on a set of nodes

and arrows

Arrow decorations in GMF

By default, edges generated by GMF are just lines

Need to add arrowheads manually, either by setting up a point-path or creating your own

Arrow decorations - Example

Dynamic visualization

We want to change visualization based on attributes on the model elements• Ex. A predicate has been added to a node

This is not default behaviour in GMF, so it needs to be custom made

Changing view based on model attributes

Normally, GMF doesn’t change the view of an element once it has been painted

But since the view is attached to the model as a listener, we can detect changes in the model via the method handleNotifications()

Example customization – Coloring nodes

/** * @generated NOT */protected IFigure createNodeShape() { NodeFigure figure = new NodeFigure(); // checking for red color changeFigureColor(figure); return primaryShape = figure;}

private void changeFigureColor(IFigure figure) { Node node = (Node) ((View)getModel()).getElement(); if (node.getNodeTypes().contains(NodeType.RED)) { figure.setBackgroundColor(ColorConstants.red); if (node.getNodeTypes().contains(NodeType.BLUE)) figure.setBackgroundColor(new Color(null, 153, 51, 255)); } else if (node.getNodeTypes().contains(NodeType.BLUE)) figure.setBackgroundColor(ColorConstants.blue); else figure.setBackgroundColor(ColorConstants.white); node = null;}

Coloring nodes – cntd(1)/** * Need to override this to get the colorchanging bit to work */@Overrideprotected void handleNotificationEvent(Notification notification) { super.handleNotificationEvent(notification); changeFigureColor(primaryShape);}

Coloring nodes – cntd(2)

Testing

Everything in Eclipse is testable The tests may not be straightforward and

time-consuming to set up, but doable To test a Plug-in you need a Plug-in test

project

Summary

This project spans multiple areas• Modeling

• Graphical development

• Eclipse development / Plug-in development

Which means that there is a lot of documentation to go through