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Harmony: An Approach and Tool for Harmony: An Approach and Tool for Combining Semi-formal and Formal Combining Semi-formal and Formal Notations in Software SpecificationNotations in Software Specification

CS 791z Topics on Software Engineering

Instructor’s Research

April 19, 2004

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Outline

Context A Procedural Frame The Harmony Tool Conclusions

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Context: The Harmony Project

Proposal of an approach for specifying time- constrained systems (TCS) based on the combined use of UML (graphical, semi-formal notation) and Z++ (formal notation)

Topic placed at the confluence of three paradigms: object-orientation formal specification visual representation

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Context: Why Integrate?

Combine benefitsGraphical notations easy to useFormal methods precise

Different aspects of the system need different ways of description

Provide choices

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Context: Research Space and Location

  

RTnonRT

formal

non OO OO

Z

Topic location: * formal, employing an OOZ variant

* OO development, UML-based* RT modelling capability

UML

formal

OOZ

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Strategies for Integration

Integration of notations: Semi-formal/Formal Semi-formal/Semi-formal Formal/Formal

Types of semi-formal/formal integrations: Derivation or (simple) formalization Complementary formalization Tight integration, involving two-way translations

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Related WorkRelated Work

Similar approaches:Similar approaches: Jia’s AMLJia’s AML Noe and Hartrum’s extension of Rational Rose Noe and Hartrum’s extension of Rational Rose France et al.’s blending of Octopus and Z France et al.’s blending of Octopus and Z Headway System’s RoZeLink Headway System’s RoZeLink Kim and Carrington’s UML/Object-Z combinationKim and Carrington’s UML/Object-Z combination

Our approach is distinct from all the above in at Our approach is distinct from all the above in at least one major aspect: variant of Z involved, least one major aspect: variant of Z involved, provisions for dealing with RTS, tight integration provisions for dealing with RTS, tight integration of notations, or type of supporting environmentof notations, or type of supporting environment

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Notations: Notations: UMLUML

“Graphical language for visualizing, specifying, constructing, and documenting the artifacts of software-intensive systems” [G. Booch]

OMG standard notation for object modeling Includes structural & behavioral model elements Extension mechanisms: stereotypes, tagged values,

constraints Support for RTS: events, signals, active classes, finite-

state machines, timing marks and expressions However, for rigorous development supplementary

formalization is necessary

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Notations: Notations: UML - Example of Class Diagram

Elevator

PositionDetector1

1

Door

1 1

CarButton

1

*

SpecialCarButton

1

*

Button

FloorButton Floor10..1

10..1

GroupIndicator

1

1

Indicator

1*

1

1serves

AlarmSystem11

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Notations: Notations: UML - Example of State Diagram

stoppedToDownentry: door.open()activity: updateRequests()exit: door.close()

movingUpentry: moveUp()activity: goToTarget()exit: stop()

stoppedToUpentry: door.open()

activity: updateRequests()exit: door.close()

idleactivity: updateRequests()

movingDownentry: moveDown()activity: goToTarget()exit: stop()

when(other_level_requestand up_to_go)

when(target_reachedand up_to_go)

when(up_target)

when(no_requests)

when(level_request and up_to_go)

when(level_request and down_to_go)

when(target_reachedand up_to_go)

when(target_reachedand down_to_go)

when(down_target)

when(no_requests)

when(other_level_requestand down_to_go)

when(target_reached anddown_to_go)

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Notations: Notations: Z++

Created by Lano and Haughton Essentially, extends Z with the class construct Closer to implementation than other formal languages Support for dealing with time in the HISTORY clause:

Temporal Logic or Real-Time Logic (RTL) formulae

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Notations: Z++ Class

ZPP_Class ::= CLASS Identifier [TypeParams] [EXTENDS Ancestors]

[TYPES TypeDefs][FUNCTIONS AxiomaticDefs][OWNS Locals][RETURNS OpTypes][OPERATIONS OpTypes][INVARIANT Predicate][ACTIONS Actions][HISTORY History]END CLASS

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Translations UML/Z++: Overview

Formalization = UML to Z++ translationFormalization = UML to Z++ translation Deformalization = Z++ to UML translationDeformalization = Z++ to UML translation Algorithms for automated translations have been Algorithms for automated translations have been

proposedproposed Formalization of both structure and behavior Formalization of both structure and behavior

Rules and principles for translating class diagrams Rules and principles for translating class diagrams (algorithm AFCD)(algorithm AFCD)

Rules and principles for translating state diagrams Rules and principles for translating state diagrams (AFSD)(AFSD)

Principles for reverse translation (ADF)Principles for reverse translation (ADF)

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A Procedural Frame

Series of activities in which model artifacts are produced

Subset of UML used (“2+1 views”) Artifacts:

UML elements: use case diagrams, scenarios, sequence diagrams, class diagrams, and class compounds

Z++ specifications: Z++ classes and statements Activities organized in stages

‘Regular’ and ‘irregular’ sequences of activities

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A A Procedural Procedural

FrameFrame

Requirements Set

UC Collection

SC Collection

1 Definition ofUse Cases

2 Elaboration ofScenarios

3A Construction ofClass Diagrams

4A Elaboration of UMLClass Compounds

4B Elaboration ofZ++ Specification

5AFormalization

5BDeformalization

UML ClassCompounds(COMP)

(CLS and CLSTD)

Z++ Specification(ZSPEC), a set of

Z++ classes (ZPPC)

Integrated UML/Z++Classes Collection

3B Specification ofSequence Diagrams

SQD CollectionCD Collection

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Regular Flow Regular Flow of Activitiesof Activities

1

2

3A

4A

5A

4B

3B

5B

Stage 1

Stage 2

Stage 3

Stage 4

Stage 5

Definition ofUse Cases

Elaborationof Scenarios

Construction ofClass Diagrams

Specificationof Sequence

Diagrams

Elaboration of UMLClass Compounds

Elaboration ofZ++

Specification

Formalization(UML to Z++)

Deformalization(Z++ to UML)

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Irregular Flow Irregular Flow of Activitiesof Activities

1

2

3A

4A

5A

4B

3B

5B

Stage 1

Stage 2

Stage 3

Stage 4

Stage 5

Definition ofUse Cases

Elaborationof Scenarios

Construction ofClass Diagrams

Specification ofSequenceDiagrams

Elaboration of UMLClassCompounds

Elaboration ofZ++ Specification

Formalization(UML to Z++)

Deformalization(Z++ to UML)

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The Harmony Tool: Characteristics

Sustains the development of combined UML/Z++ models

Operates on specification projects Monolithic construction Options for automated translations Support for class compounds Tandem mode of operation Provisions for interfacing with external tools

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Harmony: The Browser

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Harmony: Project Pane

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Harmony: New Element Selector & Legend Pane

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Harmony: Toolboxes

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Harmony: Project Loaded

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Harmony: UML Space (Class Diagram)

+updateRequests()+updateTarget()+goToTarget()+moveUp()+moveDown()+stop()

#state : ElevatorState#dir : Direction#current : unsigned int#target : unsigned int#carRequests : unsigned int [ ]#upFloorRequests : unsigned int [ ]#downFloorRequests : unsigned int [ ]

Elevator

+getCurrentFloor() : unsigned int+calculateSpeed() : double

-currentFloor : unsigned int

PositionDetector

1

1

+open()+close()+getState() : DoorState

#state : DoorState

Door

1 1

+getButtonNumber() : unsigned int-buttonNumber : unsigned int

CarButton

1

*

+getKind() : SpecialCarButtonKind-kind : SpecialCarButtonKind

SpecialCarButton

1*

+press()+turnOff()+getState() : ButtonState

#state : ButtonState

Button

+getKind() : FloorButtonKind-kind : FloorButtonKind

FloorButton +getKind() : FloorKind+setFloorNumber(in floorNumber : unsigned int)+getUpButtonState() : ButtonState+getDownButtonState() : ButtonState

#kind : FloorKind#floorNumber : unsigned int#upButton : FloorButton#downButton : FloorButton

Floor

10..1

10..1

+setIndicator(in ind : unsigned int)+resetIndicator(in ind : unsigned int)+resetAll()

-size : unsigned int

GroupIndicator

11

+turnOn()+turnOff()+getState() : IndicatorState

#state : IndicatorState#indicatorNumber : unsigned int

Indicator

1*

11

serves

+audioSignal()+visualSignal()

AlarmSystem1

1

1

*

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Harmony: Z++ Space (Class Spec)

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Harmony: Harmony: Z++ Space (Timing Constraints)Z++ Space (Timing Constraints)

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Conclusions: Summary

Pragmatic semi-formal/formal combination of notations

Formalization of UML constructs in Z++ Rigorous treatment of TCS via RTL Detailed design of the Harmony ISE Lightweight, rapid modeling process

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Conclusions: Future Work (most on Andy )

Enhancement of algorithmsEnhancement of algorithms Refinement of the tool’s functionalityRefinement of the tool’s functionality Implementation of Harmony Implementation of Harmony Syntax checker for Z++Syntax checker for Z++ More applicationsMore applications