On the verification of UML/OCL class diagrams using constraint programming

On the verification of UML/OCL

class diagrams using constraint

programming

Jordi Cabot (jordi.cabot@inria.fr)

Robert Clarisó (rclariso@uoc.edu)

Daniel Riera (drierat@uoc.edu)

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On the verification of UML/OCL class diagrams using constraint programming

1. The context: Model-driven software engineering

2. The problem: Quality assurance using formal methods

3. Our proposal: Verification using constraint programming

Index

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On the verification of UML/OCL class diagrams using constraint programming

1. The context: Models in SW Engineering

3

Modeling in engineering

4

Features that are not

relevant to the purpose of

the model are excluded

Benefits

• Simplicity

• Understandability

• Reusability

“A model is a description or

specification of a system

defined for a specific purpose”

Software models: perspectives

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Information base

(UML class diagram) Variability among products

(Feature model)

Behavior and data flow

(UML activity diagram)

Documentation and communication

“Describe how the system will work”

Reverse engineering

“Guide the implementation”

Code generation

Simulation

Verification and validation

“Analyze if the model is correct”

Domain-Specific Languages

Software models: applications

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2. The problem: Quality assurance

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Defects in software models

Complete

Includes all relevant info

Precise

Describes system accurately

Suitable

Useful to stakeholders

Validation

“Is it the right product?”

Verification

“Is the product right?”

Well-formed

Correct syntax

Consistent

No contradictions

Non-redundant

Lack of duplicities

B A

A

1

2

A B

C

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Model-based formal verification

VERIFICATION TOOL

?

Model

A B

C

Correctness

Property

Additional

Parameters

Designer

Formal Notation

x:y: p(x,y)

Feedback

Yes / No

Formal proof

Example / Counterexample

Reasoning Engine

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Trade-offs in verification

Verification

Automation

Is user intervention required?

Efficiency

Required memory and CPU

Expressiveness

Type of supported properties

OCL invariants?

Precision / coverage

Undetected errors?

False alarms?

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3. Our proposal: Constraint programming

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Constraint Satisfaction Problems

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Variables

Domains

that should have a value

Define a problem declaratively in terms of...

Constraints

set of potential values

restrictions on the legal values

Then, let a solver find the solution (if any).

Example: N-Queens Problem

Our proposal: UMLtoCSP

UMLtoCSP

?

Model

A B

C

Correctness

Property

Finite

Bounds

Designer

Formal Notation

CSP

Feedback

Example or ?

Counterexample or ?

Reasoning Engine

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2. The designer needs to select suitable bounds

– Small enough to allow efficient analysis

– Large enough to provide confidence in the result

1. Answer may be inconclusive

– There may be no (counter)example within the bounds

– No assurance of what happens outside the bounds

Cons

Pros 1. Automatic analysis of expressive models (including OCL)

2. Efficient solvers available

– Execution time can be controled by tuning bounds

3. Useful feedback (when it is available)

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Strengths and weaknesses

Thanks for your attention!

Further details

http://gres.uoc.edu/UMLtoCSP UMLtoCSP homepage

Full paper

Contact Robert Clarisó (rclariso@uoc.edu)

Jordi Cabot, Robert Clarisó, Daniel Riera.

On the verification of UML/OCL class diagrams

using constraint programming.

Journal of Systems and Software 93: 1-23 (2014)

Acknowledgements

EIMT.UOC.EDU GRES-UOC @ IN3

GMC @ UPC

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