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Eclipse Modeling Day/Session Abstracts Toronto

Building DSLs with Xtext

Moritz Eysholdt, itemis

Domain-Specific Languages (DSLs) are becoming more and more popular, allowing developers to express their intent more precisely and with less syntactic noise. DSLs can be built on top of a host language (like Java or Ruby), which are referred to as "internal DSLs". External DSLs are far more flexible in terms of language design: you can define any desired grammar, you can define domain specific constraints and error messages and you can process the DSL in a concise manner because it can either be interpreted or transformed into the code of any language by a generator.

Xtext, which is a part of the Eclipse Galileo release, is a framework for developing textual domain-specific languages. Given an EBNF-style grammar, Xtext automatically generates an Ecore meta model and a rich-featured, fully configurable, text-based DSL editor, including features such as syntax highlighting, hyperlinked reference navigation, reference look-up, code completion, formatting, an outline and so on. The default implementation can easily be customized.

In this session, we will explain what DSLs are and why you should care about using them. After a short introduction, we will show how to develop DSLs with Xtext during a live demo. You will see how to define a grammar for a DSL and create a full-blown editor for this DSL. We will also show how to apply code generation that allows you to transform your DSL scripts into running software.

Modeling on an Enterprise Scale

Eike Stepper, Consultant

Persisting models in files is not always straightforward. Often you’ll need multi-user support or transactionality with fined-grained object-level locking, i.e., database-style persistence. I’ll introduce the CDO Model Repository, which comprises three tiers and is a general runtime platform for distributed shared models.

We'll not dive into too many implementation details of CDO. I'll rather provide you with a functional overview and explain the benefits in the context of some typical enterprise scenarios. After attending this talk you'll never want to live without the CDO Model Repository in your modeling projects.

Modeling is a Developer's Best Friend

Ed Merks, Eclipse Modeling Project

EMF provides a framework for converting other forms of model description to Ecore, for example, annotated Java, XML Schema and UML. From that, it generates a complete Java implementation of the model, platform neutral editing support for manipulating and viewing instances of the model, as well as an integrated Eclipse IDE or RCP editor for editing instances. Alternatively, this same instance behavior can be emulated dynamically, without generating any code. Both approaches support rapid prototyping to validate design decisions early. Because the template based generator (JET) supports merging, generated code can be hand specialized without losing the ability to regenerate after modifying the model, thereby providing the best of both modeling and programming worlds. By eliminating the menial tasks that are easily automated, such as implementing serializers and deserializers, EMF facilitates a tremendous productivity boost: the skilled developer can focus on the creative tasks rather than repeating the mundane tasks again and again. Utilities such as a copier for cloning instances, an equality tester for comparing instances and a change recorder for tracking instance modifications with playback or undo support, are really just the icing on the cake. This presentation will demonstrate the basic concepts needed to get started with a pragmatic focus on how to use the tools.

Papyrus: Advent of an Open Source IME at Eclipse

Kenn Hussey, Zeligsoft

The role and significance of open source in system design is constantly increasing. Organizations are now widely using open source solutions for many key aspects of development, including real time operating systems, compilers, debuggers and middleware. The key benefits provided by open source include greater control over product roadmaps, lower costs, more features, better support and avoidance of vendor lock-in. Modeling technologies are becoming increasingly relevant to consumers of open source; indeed, with the incubation of e4, modeling has found a home at the very heart of the Eclipse platform itself. With the commoditization of modeling tools at Eclipse, there is a growing interest in the development of an open source tool suite that supports model-based software engineering (MBSE).

In this session, we present Papyrus, an open source, Eclipse-based, integrated modeling environment (IME). The goal of Papyrus, a sub-project of the Model Development Tools (MDT) project, is threefold: first, to provide a complete, efficient, robust, methodologically agnostic modeling tool to both industry and academia; second, to provide an open and flexible facility for defining and utilizing domain-specific languages that allow for customizable validation and code generation; and third, to enable the integration of key MBSE elements such as action languages and model-level debuggers. Initially focused on UML and related standards (such as SysML and MARTE), Papyrus includes a backbone that allows integration of multiple editors and promises all the features that one would expect in an IME, such as a model exploration view, standards-compliant editors, customizable property views and support for collaborative work, advanced profile management, and customization though preferences and extension points. We will explore Papyrus from the perspective of its three communities (developers, vendors, and users) while providing an overview of what functionality currently exists, what we expect to achieve in the first major release (Helios) and where we see the project going in the future.

Converging Textual and Graphical Editors

Moritz Eysholdt, itemis

When speaking about modeling, s conflict often comes up whether graphical notations or textual notations are superior. However, both sides have their advantages. For a textual notation existing tool, support can be used for comparing, merging and versioning. Furthermore, the well-known comfort of editing a text via the keyboard is present. There are established syntaxes to express expression statements. Graphical notations, however, have their advantages when the layout of a diagram can help the viewer to understand the underlying semantics. This is the case when, for example, flow or hierarchy is important.

Why not combine the advantages of both worlds? This will be done within this presentation. On the foundation of EMF, Xtext as a textual model framework will be combined with GMF as a graphical modeling framework. Thereby, a model will have a textual notation as well as a graphical notation and both will be editable. The following questions will be discussed:

  • What are the strengths and weaknesses of textual notations and what are the advantages of graphical notations?
  • How do you design a graphical notation for parts of the model?
  • Under which circumstances should the graphical and textual notation share a common abstract syntax? What are the advantages and where are the limits?
  • How do you synchronize an Xtext editor's and a GMF diagram editor's contents?
  • What are the places where concepts of Xtext and GMF can support each other? Example: validation.

There will be a demo to show the feasibility of the suggested concepts and to provide a first impression of the editor's look and feel.

The approach has been implemented in an industrial project by the presenter. Therefore, the contents are based on first-hand experience.

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