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

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

Problems and Motivation 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. SEL, East China Normal University Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

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

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

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

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

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

Triple-C Model 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. SEL, East China Normal University Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

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

Basic ideas of our approach 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 SEL, East China Normal University

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

JCMPL Language (Cond.) out in ScannerParser //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; } SEL, East China Normal University Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

Generated Style 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 SEL, East China Normal University

Dynamic interface matching 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. SEL, East China Normal University Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

Checking conformance in impl. 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). SEL, East China Normal University Guoqing Xu, SACT-01, Pusan, Nov.30th, 2004

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

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

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

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

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

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.

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

Thank you