1. Nigel Baker UWE & CERN/EP-CMA Component Based Approach to Scientific Workflow Management The C.R.I.S.T.A.L. Project ( C ooperative R epositories & I nformation S ystem for T racking A ssembly L ifecycle) CERN, LAPP(Annecy), KFKI(Budapest), UWE(Bristol) ACAT 2000 Fermi National Accelerator Laboratory

2. Nigel Baker ACAT ’2000 Presentation 2 The Problem Domain The design of a production & assembly control system(CRISTAL) for the construction of the CMS ECAL detector using workflow(WfM) & product data management (PDM) techniques.

3. Nigel Baker ACAT ’2000 Presentation 3 The Product Family Problem The design of a production & assembly control system for the construction of ANY detector or system. Software Product 1 Software Product 2 Software Product 3 A collection of software systems with the same application area.

4. Nigel Baker ACAT ’2000 Presentation 4 Product Line Engineering Product line engineering defines a generic infrastructure, reusable across a family of target products. Requires analysis of common and variable product characteristics  defining the scope of reuse  identification of reusable components  identification of suitable level of generality. Requires building and evolving a generic infrastructure to  support application engineering  exploit common characteristics  integrate variant and optional features

5. Nigel Baker ACAT ’2000 Presentation 5 Software Product Lines Software Engineering Institute (CMU) Software Product 2 Software Product 3 Software Product 1 Market Strategy / Application Domain Architecture Components Pertain to Share an Are built from

6. Nigel Baker ACAT ’2000 Presentation 6 History of Reuse in Computing subroutines modules objects components patterns, frameworks models adhoc reuse systematic reuse large grain reuse

7. Nigel Baker ACAT ’2000 Presentation 7 Experiences of Reuse Our experience over the past 10 years of building Object Oriented systems is that:-  Most reuse has come from higher level design patterns (in recent years captured and described in UML)  Very little code has been reused, a small amount of class library reuse mainly in the client user interface of systems So why so little reuse at the code level?  Because the underlying software technology moves so fast, smalltalk, C++, Java, EJB, COM+, Active X, CORBA, C#  We are in a Fashion Industry!

8. Nigel Baker ACAT ’2000 Presentation 8 Why UML Has Helped Provides a structure for problem solving: allows to contemplate problems that won’t fit on the back of an envelope Usually the great thing about standards is that there are lots to choose from. However UML is the universal OA&D modeling standard. Used by OMG companies and Microsoft. UML is an OMG Standard and tightly coupled into OMG’s Distributed Object Architecture.  UML 1.1 1997, UML 1.3 1999

9. Nigel Baker ACAT ’2000 Presentation 9 UML a Key Part of OMG OMA UML Modeling CORBAservices CORBAfacilities Business Object Facility* Common Business Objects* CORBA Domains CORBA Domains CORBA Domains Meta-Object Facility SECURITY IDL Interfaces, Mappings, & ORB Realtime*, Embedded* options Interoperability: IIOP, Asynch* Components*, Scripting* Analysis & Design; Metadata

10. Nigel Baker ACAT ’2000 Presentation 10 Domains in the OMG OMA CORBAservices Horizontal CORBAfacilities BOF, basic Business Objects & Framework Financial Objects Transprtation Objects E-Commerce Objects Healthcare Objects Telecom Objects Manufctring Objects Accounting Banking Insurance PDM Tele Netwk Mgmt Shop Floor Auto ERP Medical MPI Tele Services Stream Control EC Services E-Payment Dental Marine Rail Offer Loc/Trade Intermodal

11. Nigel Baker ACAT ’2000 Presentation 11 Metamodeling types type relations type schemas Domain X Domain Y Set of constructs for OO information modelling meta types meta relations meta schemas Defines a language for specifying metamodels Defines a language for specifying a particular information domain.

12. Nigel Baker ACAT ’2000 Presentation 12 What is a Design Pattern ? ABC B C A Problem Solution A Design Pattern  is a solution schema expressed in terms of objects & classes for recurring design problems.  Describes (UML) the elements that make up the design, their relationships, responsibilities and collaborations.  Describes heuristics for use & applicability. (Not modeled in UML)

13. Nigel Baker ACAT ’2000 Presentation 13 What is a Design Pattern ? cont.. A Design Pattern  Documents proven design experience  Specifies concepts above the level of individual classes and objects  Provides a common vocabulary and concept understanding. Patterns have well known names. UML 1.4 Notation

14. Nigel Baker ACAT ’2000 Presentation 14 What is a Framework ? UML 1.4 draft:  A Framework specifies a reusable architecture for all or part of a system.  May include reusable classes, patterns or templates.  When specialized for a particular application then called application frameworks. > Notation

15. Nigel Baker ACAT ’2000 Presentation 15 What is a Component ? UML 1.4 draft:  A modular replacement & significant part of a system that packages implementation & exposes a set of interfaces.  It represents the physical implementation of part of the system, and may include software code( source, binary, executable) or their equivalents, such as scripts.  Typically implements one or more classes, and exposes one or more interfaces. Notation Alternative Definition A component is something that is selling really well at the moment.

16. Nigel Baker ACAT ’2000 Presentation 16 Why Components ? Programming by assembly (manufacturing) rather than by development. Reusing existing software parts. Allows reuse lower down the software engineering process. Time to market It is in fashion!

17. Nigel Baker ACAT ’2000 Presentation 17 Specification to Realisation B C A Specification Realisation How does a class in UML become a component?  There are many ways to do it!  There are several component models (EJB, COM+, CORBA CCM).The emphasis of these models is on implementation.

18. Nigel Baker ACAT ’2000 Presentation 18 EJB Example HomeObject RemoteObject > ContextObject > StackImpl > StackHome creat( ….) FindbyPrimaryKey(...) > Stack PushItem(..) PopItem(..) call Specification Elements Realisation Elements call

19. Nigel Baker ACAT ’2000 Presentation 19 UML Requirements UML model elements are required to describe  the relationship between specification and realization component constructs.  Relationship between component deployment elements and UML model elements. UML extensions to be able to forward/reverse engineer from UML to components.

20. Nigel Baker ACAT ’2000 Presentation 20 UML Roadmap UML 1.4 Recommendations  support components at an earlier phase of the software life cycle Focal Class - core logic of components AuxiliaryClass - helper classes  clarify how subsystems, components and classes are combined UML 2.0 (2002) Roadmap  Improve notations and semantics to support component development

21. Nigel Baker ACAT ’2000 Presentation 21 Component Development Methods Catalysis  complicated  unfocused Unified Process  complicated  limited view of components KobrA  product line engineering in mind  component technology compatible

22. Nigel Baker ACAT ’2000 Presentation 22 Concluding Thoughts Component technology is still at the beginning of its adoption curve. No mapping between UML and common component technology at the moment. It appears that UML will evolve to meet the requirements of components. Component based methodologies and Case Tools are work in progress.