JCMP: Linking Architecture with Component Building

1. SACT-01, Pusan, Nov. 30th, 2004 A previous version has been presented at poster session of ACM SIGSOFT 04 FSE-12 conference. JCMP: Linking Architecture with Component Building Guoqing Xu, Zongyuan Yang and Haitao Huang Software Engineering Lab, East China Normal University

2. Outline SEL, East China Normal University • Introduction and Motivation • Our Techniques --- Triple-C Model --- JCMPL language ---JCMP toolset • Analysis Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

3. Problems and Motivation SEL, East China Normal University • Two basic characteristic of components defined in the architecture: --- Conform to the architecture Follow the three criteria identified in [LV95] --- Support a great deal of flexibility A protocol or style is needed to support the independent building for the composite adaptation. • These two issues are far from orthogonal although their concern is different. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

4. SEL, East China Normal University Enforce the architectural conformance (current research) • Three criteria identified in [LV95] ---Decomposition easy ---Interface conformance easy ---Communication Integrity hard Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

5. SEL, East China Normal University Enforce Communication Integrity (current research) • Ask implementers to follow style guidelines (Rapide with C2 style [Luc96]) --- not enforced automatically • Unify implementation and architecture in one language. (ArchJava [ACN02]) --- doesn’t support architecture design. • Both don’t consider composite adaptation issues. --- there exists the direct client-server relationship between components. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

6. SEL, East China Normal University Composite Adaptation (Current Research) • Use Module Interconnection Languages (MILs) to describe use relationship. --- Jiazzi or Knit • Use on-demand remodularization. --- pluggable composite adapter[MSL01] • They don’t describe data and control flow between components and therefore cannot enforce communication Integrity. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

7. Problem conclusions SEL, East China Normal University • Current solutions to either of two issues don’t deal with another. • How to support composite adaptation in the context of architectural constraints? Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

8. Outline SEL, East China Normal University • Introduction and Motivation • Our Approach --- Triple-C Model --- JCMPL language --- JCMP toolset • Case study and Analysis Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

9. Triple-C Model SEL, East China Normal University • Component-Communicate-through-Connector. • It extends the three criteria in [LV95] in two aspects: --- A concrete connector in the implementation for each abstract connector in the architecture. --- Concrete connectors are used as wrappers to transfer the service flow between the components. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

10. Model Overview SEL, East China Normal University Currently the connector • Specify the communication permission in the arch. • Used as wrapper or glue code to transfer the methods invocation. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

11. Basic ideas of our approach SEL, East China Normal University • Linking architecture with component building (composite adaptation). • The key technique is to automatically generate the connector impl. from connector spec in the arch. • We made a JCMP system: --- an ADL: JCMPL --- a toolset: JCMP JCMP/Compiler JCMP/Match JCMP/Checker JCMP/Kernel Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

12. JCMPL Language SEL, East China Normal University • It uses the Java like grammar at an abstract level. • It is not only an ADL, but also an IDL. • It describes only abstractions, without any detailed type operations. • Translated by JCMP/Compiler to the implementation skeleton. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

13. out in Scanner Parser JCMPL Language (Cond.) SEL, East China Normal University //Parser.jcmpl public PrimComponent Parser{ public port in{ RequireInterface r{ Token nextToken()throws ScanExceptions; }; } } Public PrimComponent Scanner{ public port out{ ProvideInterface req{ Token next(); }; } } A Compiler Model public AdvancedComponent Compiler{ public port in{ RequireInterface get{ ... InputStream getInputStream() }; } public port out{ ProvideInterface err{ Integer getErrCode();... }; } Scanner scanner = new Scanner(); Parser parser = new Parser(); connect sanner.out, parser.in; } Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

14. Generated Style SEL, East China Normal University • A concrete connector is generated. • The component only requests the services from the connector and publishes their provided services. • The connector performs the dynamic matching and transfer the invocation. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

15. Dynamic interface matching SEL, East China Normal University • Searching for a pair of “require-provide” methods which match each other in semantic from two connected ports. • Based on JML Spec. of each method. • The matching strategy match_jcmp/match (P , R) = (Rpre => Ppre) ^ ( (Ppre^ Ppost) =>Rpost ) • Run P and R with test cases to watch whether their behaviors are observably equal. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

16. Checking conformance in impl. SEL, East China Normal University • JCMP/Checker instruments methods with arguments of primitive types. • It uses both architecture and implementations as input to check whether they conform to each other. • If the impl. does not conform to the arch., JCMP/Checker reports errors; otherwise, it compiles the impl. Into the bytecode files (.class). Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

17. SEL, East China Normal University Why it works—enforce communication integrity in impl. • All interface methods are generated as private. This enforces that all interface methods cannot be directly called. • The only way to call an interface method is through connector, which uses reflection to suppress access checking. • The connector is generated automatically from connector spec., and methods comm. In impl. is therefore enforced to conform to its spec. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

18. SEL, East China Normal University Why it works—support composite adaptation • Concrete connector serves as glue codes. • When a component is being built, if it requires a service, only requesting this from the conn. • Conn. uses JCMP/Match to find the suitable method, calls the method, and finally returns the value back when the system is integrated. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

19. Outline SEL, East China Normal University • Introduction and Motivation • Our Techniques --- Triple-C Model --- JCMPL language ---JCMP toolset • Analysis Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

20. SEL, East China Normal University Performance Issues • The cost in running JCMP system has two components: --- the runtime cost of type reflection. --- the extra cost of invocation transfer through the connector. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

21. SEL, East China Normal University Experiment • Construct a linked list with a given array of integers. construct (int[] nodes) • Retrieve a node from the given node ID after the list is constructed. retrieve (Integer index) Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

22. SEL, East China Normal University Comparisons Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

23. SEL, East China Normal University Analysis Summary • We found out that encapsulating the parameters of primitive types into objects took tremendous amount of time. • The cost of method invocation through connector was not obvious. • Since JCMP uses reflection, we suggest objects be used as data to be transferred, rather than primitive values. Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

24. Future Work • JCMPL is only used at the design level, without supporting the dynamic description of runtime architecture. • Architectural styles should be considered. • The performance should be optimized in the way of having some other techniques to replace the Java reflection.

25. Conclusions To link architecture with component building, we made: • Triple-C model • JCMP toolset --- an ADL JCMPL --- JCMP system

26. Thank you