A Formal Foundation Supporting MDD

1. A Formal Foundation Supporting MDD --- ZOOM Approach Hongming Liu Lizhang Qin 11/08/2003

2. Agenda • Background of MDD • A formal foundation for meta-modeling • Formal OO Model • Tools Support • Comparison to other approaches

3. Model Driven Development(MDD) • MDD is the notion of constructing a model that can then be transformed into a real system • MDD moves the development focus from code to model • Advantages of MDD

4. Requirements of MDD the models must capture information from three dimensions: • The functional requirements • The architectural requirements • The target environment requirements

5. Characteristics of MDD we argue that an MDD infrastructure requires models to be • precise • analyzable • transformable • executable

6. Meta-Modeling • meta-model: a model of the modeling language • OMG’s MDA(Model Driven Architecture) framework • self-defined meta-meta-model: MOF(Meta-Object Facility)

7. OMG Meta-Modeling Architecture • M3: the meta-meta-model level (contains only the MOF) • M2: the meta-model level (contains any kind of meta-model, including the UML meta-model. • M1: the model level (any model with a corresponding meta-model from M2) • M0: the concrete level (any real situation represented by a given model from M1)

8. A Formal Foundation for Meta-Modeling • limitations of MOF • need a meta-modeling language that provides both formal syntax and semantics. • an alternative approach to MOF that uses the ZOOM as its meta-modeling language

9. Z-based Object-Oriented Modeling(ZOOM) • based on the formal specification notation Z • extends Z to support these object-oriented concepts. • providing textual and graphical representations of models that are consistent with UML • adopts a syntax that is similar to commonly used programming languages such as Java or C++.

10. Core ZOOM(ZOOM-C) Core ZOOM(ZOOM-C) is based on Z, and can be used to describe UML semantics. Similarly, UML semantics can be formally reduced to ZOOM and thus to Z. This provides a formal foundation to UML meta-modeling.

11. ZOOM as a Meta-Modeling Language Part of MOF Model Structure from OMG MOF Specification

12. ZOOM as a Meta-Modeling Language typedef MM = ModelElement <=> ModelElement; //a relationship between ModelElements typedef MN = ModelElement -> NameSpace;//a function map from ModelElement to NameSpace MM Depends_On; //declare a global variable of type MM MN Contain; //declare a global variable of type MN struct ModelElement { //struct definition Public String name, annotation; Public : noaccess String qualifiedName; Set[ModelElement] dependent, provider; NameSpace container; Invariant { //invariant definition dependent == DependsOn.image(this); provider == DependsOn.invert().image(this); container == Contain.invert(this); } } struct NameSpace extends ModelElement { Set[modelElement] containElement { containElement == contain.invert(this)} } ZOOM Specification of core structure of MOF model

13. ZOOM Models Structural Model Behavioral Model UI Model Event Model ZOOM Models

14. Structural Model • Defines the functional part of the system using object-oriented concepts • Consists of a series of diagrams along with the formal specifications described by ZOOM-C module zoom.examples.addressbook; class AddressBook { String title; List[AddressBookEntry] entries; delegates entries; // delegates the operations to entries Set[AddressBookEntry] search(SearchCriterion criterion) { requires { criterion != null; } ensures { search! = { AddressBookEntry entry in entries | entry.matchAddressBookEntry(criterion) @ entry } } } }

15. Behavior Model • The central communication mechanism that links the structural models and UI models • Uses a formalized state diagram to specify the dynamic aspects of a system fsm MachineserviceStat() { state inService { fsm MachineopStat () { state standingBy; state turningOnMotor; state accelerating; state running; state decelerating; transition standingBy to turningOnMotor : operatorStartsMachine(runSpeed) {safetyBrake.turnOff(), mainMotor.turnOn(runSpeed, out runSpeedOK)}; transition turningOnMotor to standingBy : standBy [runSpeedOK != TRUE] {mainMotor.turnOff(), safetyBrake.turnOn()}; transition turningOnMotor to accelerating : accelarate [runSpeedOK == TRUE]; } }; state inRepair; state waitingForRepair; transition inRepair to inService : returnToService(fixDate); transition waitingForRepair to inRepair : beginMaintenance(maintDate); transition inService to waitingForRepair : removeFromService(reason) {maintShop.notify(self, reason)}; }

16. UI Model and Event Model • UI Model • Define a hierarchical description framework containing a set of predefined UI components • Designers can specify related visual attributes and the events that can be generated or consumed by the component Event Model Event UI Event FSM Event Standard Event User-Defined Event

17. Tools Support For Automation • Basic Language Support Tools • Model Validation Tools • Model Verification Tools • Transformation Tools

18. Basic Language Support Tools • Lexer • Parser • Type Checker • UML Mapping Tools • Model Editing Tools

19. Model Validation Tools • Interpreter • ZOOM-E • A subset of ZOOM • Provides imperative features similar to those in Java. • Not used frequently in ZOOM model. • Be used to exhibit the behavior of implementation specified by ZOOM-E • Animator • Provides a way for designers to verify their formal model. • “virtually” executes models without an implementation • Introduces a default model implementation that is consistent with the formal specification using ZOOM-E • Calls interpreter to execute the implementation.

20. Model Verification Tools • Automated Theorem Prover • Static Analyzer • Unit Test Generator

21. Transformation Tools • Code Generator • Generates the implementation conforming the formal models, for example, a method body based on the formal pre- and post-conditions • Select different target runtime environments • Adjust XFR(Non-functional Reuqirement) parameters, for example, security/performance.

22. Comparison • ZOOM provides a high level of abstraction • ZOOM separates views from models • ZOOM provides a set of automated tools to support the design and development process

23. THANK YOU Questions and Comments?