Documenting Evolving Software Systems through

Reuse ContractsKim Mens

Patrick Steyaert

Carine Lucas

Programming Technology Lab,Vrije Universiteit BrusselOOPSLA’96 Workshop on Object-Oriented Software Evolution and Reengineering.

Monday, 7 October 1996.

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Managing Evolution

Managing Evolution of software systems =Managing Dependencies between system parts

MinimiseDependencies

Document Dependencies:“Reuse Contracts”

How to cope with change and evolution ?

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Managing Dependencies

Minimise dependencies

Most changes have local impact,

local changes

change

propagation

evolution evolution

but ...... some changes cannot be kept local.

Document dependencies

4

Minimising Dependencies

Evolution

How to cope with change and evolution?

Minimise dependencies between system parts!

Most changes have local impact.

local changes

BUT ...

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Documenting Dependencies

Evolution

Some changes cannot be kept local.

Need for documentation of dependencies.

propagation of change

change

6

Reuse Contracts: Documenting Evolving Software Systems.

Documenting dependencies:

• Which parts depend on which other parts? where will problems occur?

• How do they depend on each other? what is the problem? how can it be solved?

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Evolution in Class Hierarchies

Abstract A

SubClass B

SubClass C

Abstract A’

SubClass B’

SubClass C’

parent classexchange

?

Need for documentationof dependencies

Case Study:

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Conflicts: Inconsistent Methods

Set

add(Element)addAll(Set)

CountingSetadd(Element)

OptimizedSet

addAll(Set)

add(Element)addAll(Set)

CountingSetadd(Element)addAll(Set)

count+1 count+1

Not all elementsare counted

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Detecting ConflictsCoarsening

¦ addAll(Set) {-add}Set

add(Element)

CountingSet

add(Element)

Concretisation

¦ add

OptimizedSet

add(Element)addAll(Set) {}

CountingSet

add(Element)

Concretisation

¦ add

inconsistent method conflictfor add and addAll

addAll(Set) {add}

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Environmental & Tool Support

• Synchronisation: reuse contracts implementation• Detection of problems when changes are made (PROLOG)• Extraction of reuse contracts from code (Smalltalk)

reuse contractimplementation

unstable designadd(El)addAll(Set)

addAll(Set)

Warning !

add(El)

Change

synchronisation

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More about Reuse Contracts• OOPSLA’96 Technical Paper

“Reuse Contracts: Managing the Evolution of Reusable Assets”Wednesday, 9 October 1996, 11:30 am

• Home page:http://progwww.vub.ac.be/prog/pools/rcs/rc.html

• Mailing list: (also see homepage)e-mail: majordomo@cs.vub.ac.bein body: subscribe reuse