Emmerich, W

Gruhn, V

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Engineering distributed objects (EDO 99) workshop summary

UCL Discovery

Engineering Distributed Objects (EDO 99)Workshop SummaryWolfgang EmmerichDept. of Computer ScienceUniversity College LondonLondon WC1E 6BTUnited Kingdomw.emmerich@cs.ucl.ac.ukVolker GruhnInformatik 10Universit¨ at Dortmund44221 DortmundGermanygruhn@ls10.informatik.uni-dortmund.de1 THEME AND AUDIENCEThis two-day workshop will provide a forum for discussingprinciples, methods and techniques for the engineering ofdistributed objects. The intended workshop audience arepractitioners and researchers in software architecture anddistributed systems.2 RELEVANCEStandards for object-oriented middleware, such as OMG’sCORBA, Java’s Remote Method Invocation and Microsoft’sDCOM have developed and matured over the last decade.They facilitate the implementation, execution and commu-nication of distributed objects. Several products implement-ing these standards are available now and these products arebeing used in many development efforts in industry. A con-siderable number of projects, however, fail because they donot consider the differences between designing distributedobjects and building applications based on local objects.Several research communities in Databases and DistributedSystems have picked up on the topic. They are organiz-ing meetings that are concerned with how to efﬁciently im-plement middleware, integrate it with databases to achieveobject persistence, and how to administer the resulting dis-tributed systems. There is, however, no established commu-nity that is looking at distributed objects from a software en-gineering perspective. We go a step further and argue thatneither the problem, nor principles, methods and techniquesfor the systematic engineeringof distributed objects are fullyunderstood.3 WORKSHOP GOALSThis workshop will seek to achieve several goals. We wantto develop a better understanding of the differences betweendesigninglocal and distributedobjects. We believethat thesedifferencescomplicate the engineering of distributed objectsand need to be well understood. We want to identify the po-tential contributionsof related researchcommunitiesto solv-ing the problems of engineering distributed objects and de-ﬁne a research agenda that will lead to principles, methodsand techniques for this purpose.The design of distributed objects is very different from thedesign of centralized applications. These differences arisefor many reasons. Firstly, operation execution requests be-tween distributed objects are by several orders of magnitudeslower than local method calls. Secondly, a method invo-cation between local objects is synchronous while differentforms of synchronisation are needed for distributed objects.Thirdly, local objects are active throughout their lifetime,while distributed objects might have to be deactivated whennot needed for a certain period of time; hence these objectsmust be able to store their states persistently. Fourth, ob-jects whose persistent state is updateable might have to beintegrated with transaction monitors in order to implementdistributed transactions. Finally, object interactions acrosspublic networks mighthave to be secured against eavesdrop-ping, tampering and other security attacks. All these differ-ences complicate the design of distributed objects.The second workshop goal is the identiﬁcation of results de-veloped in related software engineering research disciplines,most notably software architecture, that can be applied tothe engineering of distributed objects. On the one hand, cur-rent research in software architecture is rather general. Ar-chitectural styles and architectural description languages aredeﬁned so that they can accommodate many different imple-mentations. This generality inhibits the application of thesetechniques in practice and renders architectural styles andarchitecture speciﬁcations less expressive. Moreover, it re-stricts the number of analysis techniquesthat can be applied.On the other hand, the distributed object paradigm is beingused in an increasing number of projects. We believe thatby targeting architectural styles and architectural descriptionlanguages towards implementations with distributed objects,styles and descriptions become more expressive and morepowerful analyses will be enabled. It would in addition be apowerful route for the transfer of research results into indus-trial practice and would clearly enhance the state of practicein engineering distributed objects.The third goal is the deﬁnition of a research agenda that willeventually lead to the development of industrially applica-ble principles, methods and techniques for the engineeringof distributed objects. Items on this research agenda mayinclude￿ Relation between requirements and distributed objectarchitectures.￿ Suitable architectural styles for distributed objects.￿ Relation between architecture description languagesand the interface deﬁnition languages supported byobject-oriented middleware.￿ Software processes for distributed objects.￿ Differencesbetweendistributedandlocalobjectdesign.￿ Extensionsof object-orienteddesign methodsand nota-tions for engineering distributed objects.4 WORKSHOP ACTIVITIESIndustrial case studies have been selected and they will bedistributed to all workshop attendees before the workshop.The case study include a DCOM based architecture for ex-change of real-time data feeds at the London Stock Ex-change, the use of CORBA management of mechanical andelectrical engineering data at Boeing, and a CORBA archi-tecture for on-line trading at Bull & Bear. Papers describingthese case studies will be made available for participants be-fore the workshop. Participants will be encouraged to studythe papers and prepare short presentations that indicate howthe principles, methods and techniques they propose for theengineering of distributed objects can be applied to one orseveral of these case studies.The presentations will be used to kick off extensive discus-sions. They will be organized in different sessions. Thoughthe detailed session breakdown will depend on the acceptedpapers, we currently foresee sessions on￿ requirements engineering for distributed objects,￿ architectural styles for distributed objects,￿ mapping of architecture description languages to dis-tributed objects,￿ concurrency and distributed objects,￿ testing of distributed objects,￿ persistence and transaction management of distributedobjects.5 EXPECTED RESULTSThe workshop will develop a better understanding of theproblems that occur when engineering distributed objectsand in particular the differencesbetween designing local anddistributed objects. It will identify routes for the applicationof software architecture research to distributed objects andlead to the deﬁnition of a research agenda for the engineer-ing of distributed objects.We hope that the workshop will become a focal point for aresearch community that is interested in distributed objectsfrom a software engineering point of view. We would ex-pect that the workshopwill be a starting point for continuousinteraction between workshop participants.The workshop organizers will summarize the result of theworkshop and submit a workshop report to ACM SoftwareEngineering Notes. The Case study material and the papersaccepted for the workshop will be available from the Work-shop web site http://www.cs.ucl.ac.uk/EDO99.6 ORGANIZERSWolfgang Emmerich is a Lecturer in the Department ofComputer Science at University College London. His re-search interests include requirements engineering and dis-tributed object-oriented software architectures. Wolfgang isSenior Consultant, Partner and Co-Founder of Z¨ uhlke Engi-neering GmbH. Wolfgang has consulted on several CORBAprojectsandgivennumerousindustrialtrainingsandtutorialson OMG/CORBA and distributed object technology.Volker Gruhn is an Associate Professor in the Department ofComputer Science at University of Dortmund. His researchinterests are software processes for distributed systems, ar-chitectureofelectroniccommerceapplicationsandworkﬂowmanagement. He has been chief technical ofﬁcer of a Ger-man software house called LION from 1992 to 1996. In thisposition he was responsible for a software development de-partment of 150 people.7 SUMMARYThe proposedworkshopcoversan importanttheme of stronginterest to industry in a timely manner. It builds on pastICSE workshops while having strong innovative content. Itis highly complementary to the main technical programmeof ICSE. What is badly needed in software engineering areways in which industrial practice and academic research canbe reconciled. This proposed workshop provides a focalpoint for such interaction on the engineering of distributedobjects.We hope that this workshop attracts participants, who oth-erwise would not attend ICSE but for whom the ICSE pro-gramme in general would be valuable.

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