OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 CORBA Based Jini™ - JinACE Michael Kircher, Prashant Jain, Kirthika Parameswaran

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE - Overview JinACE is a project, with the goal of implementing the Jini™ Pattern Language in programming languages other than Java. The first prototype –used C++ as programming language and CORBA as transport mechanism –provided a Lookup Service to register and retrieve services –transferred services as DLLs in sequences of octets –made use of the Service Configurator design pattern[JaSc97] to allow dynamic loading of services –used name-value pairs to describe properties

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 Extending JinACE The prototype proved that the idea is valid, but also showed some shortcomings. An understanding of component and container was needed. Why Component Technology? –Abstract services into the container –Write-once-run-anywhere (WORA™) Extending JinACE to use Component Technology –A component offers a service –A container provides basic functionality needed by all services –A Jini™ service respectively the proxy can be seen as a component that gets loaded into the address space (container) of a process

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE – CORBA Component Model Client internal Callbacks external POA Home ORB Container Component NotificationTransactionSecurityPersistence

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE - CORBA Component Model CCM is an ideal component platform –it is standardized –it has a well defined support for components –it supports multiple interfaces and navigation on them –it standardizes deployment and configuration of components CCM provides a complete framework on the client and the server side to support ad hoc scenarios –e.g. the standard component server can get enhanced to support dynamic scenarios. –CCM has well-defined deployment descriptors in the form of XML files that can be used to connect components in an ad hoc manner.

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE - CORBA Component Model CORBA Components –are described in assembly and component descriptions –have well defined assembly and component installations –define archives holding descriptions and implementations –information about dependencies to other libraries or components CORBA supports –Name Service supports lookup of references by names –Trading Service supports lookup of references by properties –Implementation Repository supports start-up of servers on demand

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE - What is missing in CCM? A lookup service that is able to hold component implementations –Component implementations have descriptors associated with them which need to be held as well. –Properties describing a service need to get associated with the component implementation

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 JinACE - Solution: Jini™ meets CCM A mixture of Jini™ and CORBA Components could provide the best of both worlds –It would enhance Jini™ communication mechanisms and available services –It would make CCM Ad Hoc Networking capable A new generation of lookup service might be needed to suit the needs Most of this applies to EJB as well!

OOPSLA 2000 Workshop “The Jini™ Pattern Language” © Michael Kircher, Prashant Jain, and Kirthika Parameswaran, 2000 References [KiJa00] Michael Kircher, and Prashant Jain, Lookup Pattern, EuroPLoP 2000 conference, Irsee, Germany, July 5-9, 2000 [JaKi00] Prashant Jain, and Michael Kircher, Leasing Pattern, PLoP 2000 conference, Allerton Park, Illinois, USA, August , 2000 [JaSc97] Prashant Jain and Doug C. Schmidt, Service Configuratior - A Pattern for Dynamic Configuration of Services, C++ Report, SIGS, Vol. 9, No. 6, June, 1997 [Mi99] Jeff Mischkinsky, "CORBA 3.0 New Components chapters,“ OMG TC Document ptc/ , October 1999 [St00] Michael Stal, Activator Pattern, http:// [HeVi99] Michi Henning and Steve Vinoski, Advanced CORBA Prgrogramming with C++, Chapter 12.6 – Evictor pattern, Addison-Wesley, 1999