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What Openflexo is

Openflexo is an open-source infrastructure for model federation. It lets you connect models that live in different technologies (spreadsheets, XML files, ontologies, databases, diagrams…) and work with them together, without exporting them or converting them into a common format first.

The problem it addresses​

A complex system is never described by one model. Requirements, architecture, safety analyses, schedules, costs and maintenance records each live in their own tool, in their own format, owned by a different team. Keeping them consistent usually means writing and maintaining chains of transformations, or checking by hand.

Openflexo takes another route. Each model stays where it is, in its original technology, and remains autonomous. A federated model does not have to own the values of its elements: it declares how to get them from the models that hold them, when they are needed, and how to send changes back.

Everything is a model​

Openflexo's approach is to consider any source of information as a model: a spreadsheet, an XML document, a database, a drawing, a document. In fact any data format is potentially a source. What makes it a model is the way it is interpreted, which can be explicit (a schema) or implicit; you tell Openflexo how to interpret it, through a technology adapter, and from then on it can be connected to the other models like any other.

How it works, in short​

  1. A technology adapter gives Openflexo access to one kind of resource: reading it, and, where the adapter supports it, creating, updating and deleting its content, and being notified when it changes outside Openflexo.
  2. A virtual model, written in FML (the Flexo Modeling Language), describes the concepts you care about and, for each property of each concept, which source it comes from.
  3. Openflexo runs the virtual model: it retrieves, combines, computes and propagates information between the sources, and it can drive graphical editors on top of it.

The model federation page explains the idea with figures, and the vocabulary page defines each term.

What the platform contains​

Openflexo is not a single application but a set of components that stack on one another:

  • Generic frameworks, useful outside model federation: Connie (expression language), Pamela (modeling framework), Gina (user interfaces) and Diana (diagrams).
  • The federation core, which runs FML.
  • Technology adapters, one per kind of resource: Excel, Word, PowerPoint, XML, EMF, OWL, JDBC, REST and others.
  • Applications built on all of the above, such as the FreeModellingEditor and the Openflexo Modeller (see the tools), a command-line interpreter and an HTTP server.

Each of these lives in its own repository and has its own version; the repository map lists them. You do not download them one by one: they come in ready-to-run packages.

What Openflexo is not​

  • Not a replacement for your modeling tools. Your spreadsheet stays a spreadsheet and your UML model stays in its UML tool. Openflexo connects them.
  • Not a single fixed language or method. FML describes how models relate; the models themselves keep their own languages.
  • Not a finished, closed product. It is an infrastructure that grew out of research work (see Research), available under the GNU GPL version 3 or the European Union Public Licence, and its components are at different levels of maturity: each technology adapter carries a status. See maturity, licensing and support.

Where to go next​