WCOP'99

Motivation

WCOP'99 seeks position papers on the important field of component-oriented programming (COP). WCOP'99 is the fourth event in a series of highly successful workshops, held in conjunction with every ECOOP since 1996.

COP has been described as the natural extension of object-oriented programming to the realm of independently extensible systems. Several important approaches have emerged over the recent years, including CORBA, COM (COM+, DCOM, ActiveX, DirectX, ...), JavaBeans.

A component is not an object, but provides the resources to instantiate objects. Often, a single component will provide interfaces to several closely related classes. Hence, COP is about architecture and packaging, besides interoperation between objects.

After WCOP'96 focused on the fundamental terminology of COP, the subsequent workshops expanded into the many related facets of component software. WCOP'99 shall emphasis architectural design and construction of component-based systems beyond ad-hoc reuse of unrelated components. In particular, a focus on component frameworks as introduced below, is suggested.

COP aims at producing software components for a component market and for late composition. Composers are third parties, possibly the end user, who are not able or willing to change components. This requires standards to allow independently created components to interoperate, and specifications that put the composer into the position to decide what can be composed under which conditions. On these grounds, WCOP'96 led to the following definition:

A component is a unit of composition with contractually specified interfaces and explicit context dependencies only. Components can be deployed independently and are subject to composition by third parties.

A problem often discussed in the context of COP are non-functional requirements or quality attributes. Another key problem that results from the dual nature of components between technology and markets are the non-technical aspects of components, including marketing, distribution, selection, licensing, and so on. While it is already hard to establish functional properties under free composition of components, non-functional and non-technical aspects seem quickly beyond controlability.

One promising key approach to establishing composition-wide properties of functional and non-functional nature is the use of component frameworks. A component framework is a framework that itself is not modified by components, but that accepts component instances as "plug-ins". A component framework is thus a deliverable on its own that can enforce (sub)system-wide properties of a component system. As such, a component framework is sharply distinct from application frameworks that are subject to (partial) whitebox reuse and that do not retain an identity of their own in deployed systems.

Topics

Topics of interest to WCOP'99 include, but are not limited to:

• design methods for component frameworks
• interoperation among component frameworks
• properties, function, non-functional, or even non-technical that CAN or that CANNOT be established by a component system architecture based on (tiered) component frameworks
• use of selected component frameworks to reduce the set of possible components in a market setting
• impact of component frameworks on independent evolution of components and component-oriented systems
• domain-specific standards for component interoperability and their impact on component frameworks and component framework design
• dynamic changes in the configuration (set of components in a system): how can components be added, replaced and removed and how can other components reconfigure themselves to cope with this
• adaptation of components and composition of frameworks
• programming language support for COP and component frameworks in particular
• performance/efficiency of component-oriented implementations and effects of component frameworks introducing a level of indirection
• impact of businesses on components and vice versa, packaging and distribution of components and component frameworks
• criticism of the suggested component framework approach

Submissions and Participation

To enable lively and productive discussions, attendance will be limited to 25 participants. To participate in the workshop, acceptance of a submitted position statement is required and at most two authors per accepted submission can participate.

Participants are expected to have read all the accepted position papers, which will be made available via WWW before the workshop.

All submissions will be formally reviewed. High-quality position statements will be considered for publication in conjunction with transcripts of workshop results. Authors of accepted papers need to participate in the workshop.

Position statements should clearly state

• how they relate to the workshop theme,
• what particular problems they address,
• what solutions they envisage,
• and why the statement is expected to be relevant to both this workshop and the community.

Important Dates

• Paper submissions: 5 April 1999
• Notification of acceptance: 3 May 1999
• Final papers ready: 24 May 1999
• WCOP'99: 14 June 1999

Workshop Co-Organizers