OASIS Variability Exchange Language (VEL) Technical Committee

VEL TC members will develop an interoperability standard that will enable the exchange of variability information among variant management tools and systems development tools. VEL will eliminate the cost of building customized interfaces by defining a standard way for information to be exchanged between tools.

Variability is a widely used model for describing common and unique features of systems at all stages of the lifecycle. It describes the ability of artifacts to be used in different contexts by changing or customizing some characteristics of them, and those changeable characteristics are localized somewhere within the artifacts.

Tools for variant management frequently interact with artifacts such as model based specifications, program code, or requirements documents. This is often a two-way communication: variant management tools import variability information from an artifact, and in return export variant configurations. For example, they need to gather information about the variation points contained in the artifact, identify which variants are already defined, and then modify existing or define new variants.

At present, however, there is no standard that would define how variation points are expressed in different artifacts. That means that a supplier who builds a variants management tool has to implement an individual interface to each tool that is used in a development process to create the corresponding artifacts.

There is currently no standardized API to support two-way communication, so variant management tools need to implement a separate interface -- and possibly a new data format as well -- for each new artifact. Worse, each variant management tool needs to do this separately. With m variant management tools and ‘n ‘artifacts, this may require the implementation of up to ‘m x n’ different interfaces.

Variant management tools and development tools inherently operate at odds with one another. Variant management tools represent and analyze the variability of a system abstractly and define system configurations by selecting demanded features. System development tools, on the other hand, are designed to capture specific kinds of information, such as requirements, architecture, component design, or tests. In order to support variable systems, development tools must either offer the capability to express variability directly or provide an add-on piece of software that does.

The goal of the OASIS Variability Exchange Language (VEL) TC is to enable the exchange of variability information among tools for variant management tools and systems development tools. VEL will eliminate the cost of building customized interfaces by defining a standard way for information to be exchanged among corresponding tools. Using VEL, a variant management tool will be able to read the variability from a development tool and pass configurations of selected system features to a development tool.

By defining a common variability data interface that can be implemented by both the development tools and the variant management tools, VEL will enable a continuous development process for variable systems and more flexible use of tools.

The TC will accept as input the following initial contributions:

• VEL Specification Document
  http://www.variability-exchange-language.org/download/variabilityexchangelanguage.pdf
• Enterprise Architect Model
  http://www.variability-exchange-language.org/download/vel_enterprise_architect_model.eap
• XML Schema
  http://www.variability-exchange-language.org/download/vel_xmlscheme
• Schulze, Michael, and Robert Hellebrand. "Variability Exchange Language-A Generic Exchange Format for Variability Data." Software Engineering (Workshops). 2015.

The TC will refine these initial contributions to produce OASIS standard specifications, including necessary supporting documentation. Further contributions, including other interfaces and domain models from TC members, will be accepted for consideration without any prejudice or restrictions and evaluated based on technical merit insofar as they conform to this charter.

The scope of the TC’s work is limited to technical refinements to the features defined in the input contributions. Modest extensions to the Variability Exchange Language that substantively increase interoperability will also be considered. However, the TC’s main focus is to refine the functionality presented in the input documents. Other contributions will be collected and can be considered in subsequent versions of the standard.

Out of Scope

The following is a non-exhaustive list provided only for the sake of clarity. If some function, mechanism or feature is not mentioned here, and it is not mentioned as in-scope in the Scope of Work section, then it will be deemed to be out of scope.

The following items are specifically out of scope of the work of the TC:

• Defining variability/variation points within arbitrary development artifacts
• Mapping of VEL constructs to any kind of development artifact
• Interaction schemes or workflows between tools
• Adding unnecessary complication to the protocol by extending beyond the scope described above

Contributions to this TC which are out of scope for this charter may be accumulated and taken into consideration for potential development of a charter for another technical committee that may be created to address future extensions or modifications to VEL.

The TC will produce within 12 to 16 months:

• an XML schema setting the vocabulary, constraints and semantics of the VEL format, and
• a written specification, describing the XML schema’s elements and attributes in plain English.

This TC will operate under the Non-Assertion IPR mode as defined in Section 10.3 of the OASIS IPR Policy document.

The VEL standard will be designed for use in automotive, avionics, automation, transportation, electronics, healthcare, and any industry where variants exist.

The anticipated audience for participating in VEL standardization and supporting its adoption includes:

• Providers of products and/or services designed to host or support systems and software development.
• Implementers of solutions that require interoperability between variant management tools and system development tools.
• Authors of other specifications that require a variability data exchange format.
• Consultants, educators, and interested parties.

The OASIS Variability Exchange Language (VEL) Technical Committee will conduct its business in English.