FWO Research Network Foundations of Software Evolution Research

FWO Research Network Foundations of Software Evolution Research Meeting Friday, September 20, 2002 Technical University of Vienna, Austria 1

Welcome by Mehdi Jazayeri 2

Today’s Schedule 9: 00 Welcome by Mehdi Jazayeri 9: 30 Overview of past activities and finances by Tom Mens 10: 00 Overview of ESF RELEASE network by Serge Demeyer 10: 30 --- Coffee break --11: 00 Talk about Evolution Taxonomy by Tom Mens 11: 30 Discussion about Evolution Taxonomy 12: 00 --- Lunch --13: 00 Summary Q&A Software Evolution by Tom Tourwe 13: 30 Discusion about Q&A Software Evolution by Serge Demeyer identification of opportunities for collaboration 15: 00 --- Coffee break --15: 30 Discussion about future activities 17: 00 End of the workshop 20: 00 --- Workshop Dinner --FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 3

Overview of past activities and finances by Tom Mens 4

Overview of finances for 2002 Ø Available budget for 2002: + rest of last year: 12394, 68 EUR 7715, 44 EUR Ø Research visits -1274, 33 EUR Ø Conferences and workshops -5662, 44 EUR Ø WOG meeting (18/1/02) 3746, 46 EUR Ø ECOOP workshop USE 457, 50 EUR Ø IWPSE 2002 450, 48 EUR Ø SEKE 2002 1008, 00 EUR Ø network lunches - 118, 40 EUR Ø special issue J. software evolution - 66, 86 EUR Ø other? Ø ? boeken mens tom 19, 81 Ø ? kost Tampa D’Hondt 319, 53 Ø Amount still available: 12988, 09 EUR Ø Organisation of this meeting -? ? , ? ? EUR Ø Barcelona evolution workshop -? ? , ? ? EUR FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 5

Detail of finances for 2002 Ø Conference and workshop fees, travel and accomodation expenses Ø WOG network meeting 18/1/2002 3746, 46 EUR Ø food and drink and room Ø Tom Mens Ø Mehdi Jazayeri Ø Raymond Boute Ø Michel Wermelinger Ø Reiko Heckel Ø Gall & Jazayeri Ø Serge Demeyer Ø Michele Lanza Ø Stephane Ducasse 316, 80 9, 30 902, 14 11, 00 377, 80 189, 90 1021, 63 10, 16 433, 42 474, 31 Ø ECOOP Workshop USE Ø Tom Mens (ws registration) Ø Tom Mens (travel costs) 457, 50 EUR 250 207, 50 Ø IWPSE 2002 450, 48 EUR Ø Michel Wermelinger Ø SEKE 2002 Ø Kim Mens FWO-WOG, September 2002, Vienna 450, 48 1008, 00 EUR 1008, 00 © Tom Mens, Vrije Universiteit Brussel 6

Detail of finances for 2002 Ø Research visits 1274, 33 EUR Ø Serge Demeyer (Dec. 2001, Bern) Ø Serge Demeyer (May 2002, Bern) Ø Tom Mens (Paderborn) 486, 00 313, 58 474, 75 Ø Lunches 118, 40 EUR Ø T Mens, K Mens, M Wermelinger 118, 40 Ø Special issue JSME Ø DHL FWO-WOG, September 2002, Vienna 66, 86 EUR 11, 60 + 55, 26 © Tom Mens, Vrije Universiteit Brussel 7

Publications in 2002 Ø Conferences and workshops Ø Conferences Ø T. Mens, S. Demeyer, D. Janssens. Formalising Behaviour Preserving Program Transformations. Proc. ICGT 2002 Ø K. Mens, T. Mens, M. Wermelinger. Maintaining software through intentional source-code views. SEKE 2002 Ø Workshops Ø T. Mens, M. Lanza. A Graph-Based Metamodel for Object-Oriented Software Metrics, Gra. Ba. TS workshop, ENTCS 72(2), 2002 Ø G. Arevalo, T. Mens. Analysing Object-Oriented Application Frameworks Using Concept Analysis. MASPEGHI workshop, LNCS, September 2002 Ø G. Arevalo, T. Mens. Analysing Object Oriented Framework Reuse using Concept Analysis. ECOOP 2002 Inheritance workshop, June 2002 Ø K. Mens, T. Mens, M. Wermelinger. Supporting software evolution with Intentional Software Views. IWPSE 2002, pp. 138 -142, ACM Press, May 2002 FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 8

Publications in 2002 Ø Books, journals and dissertations Ø Journals Ø T. Mens, M. Wermelinger. Separation of concerns for software evolution. Special issue of JSME Journal Ø Dissertations Ø T. Tourwe. Automated Support for Framework-Based Software Evolution. Ph. D Thesis, Vrije Universiteit Brussel, September 2002 Ø T. Richner. Recovering Behavioral Design Views: a Query-based Approach. Ph. D Thesis, University of Bern, May 2002 Ø Books Ø S. Demeyer, S. Ducasse, O. Nierstrasz. Reengineering Patterns. Morgan Kaufmann, 2002 FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel Object-Oriented 9

Overview of ESF RELEASE by Serge Demeyer 10

ESF RELEASE Title: Formal foundations of software evolution Funding: FWO Flanders Duration: 1/1/2001 – 31/12/2005 Funding: 61973 EUR TUD-DE In Belgium UCL RUG KUL UPB-DE UL-PT UA VUB TUV-AT UB-CH SER-NL SU-IT IC-UK LSR-FR FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel ESF-RELEASE FWO-WOG Abroad Title: Research links to explore and advance software evolution Funding: European Science Foundation Duration: 1/7/2002 – 31/12/2005 Funding: 93660 EUR 11

ESF RELEASE Ø Proposed network activities Ø Establish a sound scientific research method Ø (Lehman and Ramil activity coordinators) Ø Set up evolution benchmarks Ø (Serge Demeyer activity coordinator) FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 12

ESF RELEASE Ø Network convenors Ø Tom Mens (VUB-BE) Ø Serge Demeyer (UA-BE) Ø Coordination committee Ø Giulio Antoniol (SU-IT) Ø Jan Bosch (SER-NL) Ø Michel Wermelinger (UL-PT) Ø Stéphane Ducasse (UB-CH) Ø Harald Gall (TUV-A) Ø Gregor Engels (UPB-DE) Ø Meir M. Lehman (IC-UK) Ø Jacky Estublier (LSR-FR) FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 13

ESF RELEASE Ø Official observers Ø Theo D’Hondt (VUB-BE) Ø José Luiz Fiadeiro (UL-PT) Ø Oscar Nierstrasz (UB-CH) Ø Mehdi Jazayeri (TUV-A) Ø Reiko Heckel (UPB-DE) Ø Jean-Marie Favre (LSR-FR) Ø Juan F. Ramil (OU-UK) Ø Advisors Ø Kim Mens, Axel van Lamsweerde (UCL-BE) Ø Chris Verhoef (UA-NL) Ø Keith Bennett (UD-UK) Ø Malcolm P. Atkinson (UG-UK) Ø Stephen Cook, Rachel Harrison (UR-UK) Ø Reidar Conradi (UST-NO) Ø Dag Sjøberg (UO-NO) FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 14

ESF RELEASE Ø Distribution of responsibilities Ø Network convenor Ø Treasurer Ø Website and mailing list manager Ø Report manager Ø Workshop coordinator Ø Meeting coordinator Ø Activity coordinators FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 15

Evolution Taxonomy by Tom Mens in collaboration with Jim Buckley, Awais Rashid, Matthias Zenger 16

Evolution Taxonomy Ø Taxonomy of software evolution based on mechanisms of change and factors that impact upon these mechanisms Ø (ECOOP USE 2002 working group) Ø Six “dimensions” of properties Ø Temporal properties (when? ) Ø Change properties (what? ) Ø Drivers of change (who? ) Ø Object of change (where? ) Ø Change process (how? ) Ø System properties FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 17

Evolution Taxonomy Ø Related work: categorising the “why” of software evolution Ø based on the “purpose” of software changes Ø Lientz&Swanson 1980 Ø perfective / adaptive / corrective maintenance Ø Chapin et al. 2001 Ø evidence-based classification of 12 types of software evolution Ø evaluative, consultive, training, updative, reformative, adaptive, performance, preventive, groomative, enhancive, corrective, reductive FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 18

Evolution Taxonomy Ø Use the taxonomy to Ø Provide an overview of the domain of software evolution Ø Position individual software evolution tools and techniques Ø identify their strengths and weaknesses Ø Compare and combine software evolution tools and techniques Ø choose the best one among different alternatives Ø find out whether two tools are complementary or overlapping Ø Evaluate the use of a tool or technique in a particular evolution context FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 19

Evolution Taxonomy System properties Change properties (what) openness safety invasiveness activeness Change process (how) plan control effect type availability measure verify CHANGE granularity locality scope change history driver automation artifact distribution Object of change (where) FWO-WOG, September 2002, Vienna time of change Temporal change properties (when) frequency Drivers of change (who) © Tom Mens, Vrije Universiteit Brussel 20

Evolution Taxonomy Ø Temporal properties Ø Time of change Ø time when a change is requested Ø time when the change is prepared Ø time when the changes becomes available for execution Ø time when the change is executed Ø Change history Ø Versioning Ø Change frequency FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 21

Evolution Taxonomy Ø Temporal properties Ø Change history Ø sequential / parallel versions Ø synchronous / asynchronous Ø divergent / convergent changes (merging) Ø invasive (destructive) / non-invasive changes FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 22

Evolution Taxonomy Ø Drivers of change Ø Distribution Ø local / distributed Ø Degree of automation Ø automatic / interactive / manual Ø Role Ø person requesting the change Ø person making the change Ø person evaluating the change Ø manager approving the change FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 23

Evolution Taxonomy Ø Change properties Ø Type of change Ø structural versus semantic changes Ø Effect of change Ø addition / subtraction / modification Ø Safety Ø type safety Ø backward compatibility safety Ø semantic safety (impossible) Ø Invasiveness FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 24

Evolution Taxonomy Ø Object of change Ø Artifact being changed Ø documents, requirements specification, analysis and design models, source code, tests, binaries, executables, architectures, … Ø Granularity Ø from very coarse to very fine granularity Ø Locality of change Ø local/propagated/global Ø Scope of change Ø to different kinds of artifacts? FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 25

Evolution Taxonomy Ø System properties Ø Activeness Ø Passive = changes are driven externally Ø Active = system drives the changes itself (e. g. by monitoring events) Ø e. g. dynamic reconfiguration Ø Openness Ø Open system = explicit provisions are built in the software to make it easier to evolve Ø e. g. framework, plug-ins, templates, reflection Ø Availability Ø system must keep running under all circumstances FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 26

Evolution Taxonomy Ø Change process Ø Plan Ø e. g. using change request forms Ø Control Ø e. g. with or without versioning; extreme programming Ø Measure Ø e. g. impact analysis, effort estimation, evolution metrics, estimating the size of a change, … Ø Verify FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 27

Evolution Taxonomy Ø Validation: Apply the taxonomy to a number of tools Ø Refactoring Browser, CVS, e. Liza, … FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 28

Evolution Taxonomy Refactoring. Browser CVS e. Liza change history irrelevant parallel asynchronous sequential change frequency arbitrary distribution local distributed automation semi-automatic time of change temporal properties drivers of change fully automated role type of change properties structural any semantic static: more or less no ? effect of change safety invasiveness FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 29

Evolution Taxonomy object of change Refactoring. Browser CVS e. Liza artifact source code file executable code granularity several classes / methods file locality local changes with low impact scope system properties activeness passive active openness source available / reflection open source / add ons / plug ins no plan irrelevant yes control irrelevant yes availability change process measure verify FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 30

Evolution Taxonomy Ø Apply the taxonomy to the WOG-Evol network Ø Techniques Ø Graph rewriting for refactoring (VUB, UA) Ø Architectural reconfiguration (Lisbon) Ø Coordination contracts (Lisbon) Ø Model transformations (Paderborn) Ø… Ø Tools Ø Cod. Evolver (Bern) Ø Soul Ø Dup. Loc (Bern) Ø Café (Vienna) Ø… FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 31

Evolution Taxonomy time of change temporal properties change history change frequency drivers of change distribution automation role type of change properties effect of change safety invasiveness FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 32

Evolution Taxonomy artifact object of change granularity locality scope activeness system properties openness availability plan change process control measure verify FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 33

Q&A Software Evolution by Tom Tourwe 34

Q&A Software Evolution Ø General questions 1. What is software evolution (SE)? 2. Can you provide a taxonomy/classification of SE? 3. What are the most important problems in SE that need to be addressed? 1. From a practical/industrial point of view 2. From a research point of view FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 35

Q&A Software Evolution Ø Research questions 1. Which of the important SE problems do you (intend to) address? 1. In your past research 2. In your current research 3. In your future research 2. Which approaches do you take to tackle these problems? 3. How do you (intend to) validate your approach(es) in practice? 4. If you intend to validate your approach(es) on a concrete software system, what are the specific characteristics that you require of this software system? FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 36

Q&A Software Evolution Ø Contributions by Ø Serge Demeyer, Luuk Groenewegen, Mehdi Jazayeri, Kim Mens, Tom Mens, Tobias Rotsche, Tom Tourwe FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 37

Definition of Software Evolution Ø The way a software system reacts to changing requirements Ø Software evolution occurs when software artefacts change Ø Implementation, but other artefacts as well Ø Software evolution refers to the sequence of changes that software goes through from its first release until its retirement Ø Software evolution is the systematic process of extending and adapting systems, without starting from scratch Ø The realized history of the software system during its lifetime FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 38

Summary Ø Effect (result) vs. action (how) Ø Evolution vs. maintenance Ø Change of requirements vs. any kind of change Ø Evolution after first release vs. starting from scratch FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 39

Taxonomy of Software Evolution Ø Ø Ø Anticipated vs. unanticipated Version controlled or not Planned vs. unplanned Controlled vs. uncontrolled Manual vs. supported Ø E. g. by means of refactoring Ø What is being changed? Ø Requirements, design, implementation, . . Ø Type of change Ø Perfective, adaptive, corrective, . . FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 40

Taxonomy of Software Evolution Ø Granularity of changes Ø Systems, subsystems, classes, methods, statements, . . Ø Change process Ø Sequential changes, parallel changes, . . Ø Dynamic (runtime) vs. static evolution Ø Short vs. long period FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 41

Industrial Problems Ø Ø Change & Impact analysis Effort & cost estimation Change propagation Conflict detection Ø Merge conflicts, . . Ø Re(verse) Engineering Ø Software aging Ø When does software degrade? Ø Why does(n’t) it degrade? Ø How can we take countermeasures? FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 42

Industrial Problems Ø Software development/evolution processes Ø Impact of software development process on evolution Ø Organize and structure evolution process Ø Tool support for all of the above Ø Effect of training, experience, education, etc. Ø How to measure this? Ø How to teach? FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 43

Research Problems Ø Software evolution methodology Ø Techniques and tools to understand, explain & discipline software evolution processes Ø Research methodology Ø Techniques to evaluate and measure software evolution techniques & processes Ø Conformance checking Ø of design & implementation, implementation & documentation Ø Co-evolution Ø How to keep architecture, design, implementation, . . in sync FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 44

Research Problems Ø How to measure software evolution in industry? Ø Effect of technology on software evolution? Ø E. g. programming language, environment, . . Ø How to measure this effect? Ø How to improve existing technologies? Ø Use of formalisms Ø To address software evolution Ø To enable tool support for evolution FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 45

Current Research Topics Ø Re(verse) engineering (of software architectures) Ø Refactoring Ø Use of formalisms Ø Identifying refactorings that have been or should be applied Ø Conformance checking Ø Avoiding architectural decay Ø Co-evolution FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 46

Current Research Topics Ø Use of measurements (metrics) Ø for software evolution Ø to identify refactorings that have been applied Ø Analyzing evolution Ø To predict future evolution Ø To support software merging & upgrading FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 47

Approaches taken Ø Prototype tools Ø based on metamodels, formalisms, . . Ø Exploring mathematical formalisms Ø E. g. graph rewriting, metrics, . . Ø Visualization techniques FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 48

Validation Ø Case studies Ø Small vs. large scale FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 49

Requirements for Validation Ø Large scale Ø Different versions of the source code Ø Smalltalk, Java, C++, … Ø Version controlled Ø Well-documented Ø Artefacts Ø Design models, architectural views, … Ø Version controlled if possible Ø Evolution Ø Changes, transformations, … FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 50

Future activities by Tom Mens 51

Forthcoming workshops 2002 Ø October 7 -12: ICGT 2002 workshops (Barcelona, Spain) Ø Graph-based tools (7 -8 october) Ø organised by Andy Schurr, Tom Mens, Gabriele Taentzer Ø Software evolution through transformations (11 -12 october) Ø organised by Reiko Heckel, Tom Mens, Michel Wermelinger FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 52

Workshops 2003 Ø ETAPS 2003 Ø Unanticipated Software Evolution Ø 5 -6 April 2003, Warsaw, Poland Ø ECOOP 2003 Ø July 21 -25, Darmstadt, Germany Ø proposed workshop about Refactoring Ø ESEC 2003 Ø 1 -5 September 2003, Helsinki, Finland Ø IWPSE 2003: Int. Workshop on Principles of Software Evolution, 1 -2 Sept. Ø ICSM 2003 (“The architecture of existing systems”) Ø 22 -26 September 2003, Amsterdam, The Netherlands Ø Sept. 23: workshop on “Evolution of Large-Scale Industrial Software Applications” FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 53

Network Meetings 2003 Ø First ESF-RELEASE meeting Ø Date? Ø Location? Ø Next WOG-Evol meeting Ø Date? Ø Location? Ø No. E-ELISA coordination meeting Ø Date? Ø Location? Ø Official EU meeting in Brussels 11 -13 November 2002 Ø Refactoring Event Ø Date? Somewhere in 2003 Ø Location: Antwerp FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 54

Research visits 2003 Ø 1 person from Bern to Brussels Ø 1 person from Bern to Antwerp Ø 2 persons from Brussels to Bern Ø 3 persons from Brussels to Vienna Ø 2 persons from Antwerp to Paderborn Ø 1 person from Leiden to Antwerp FWO-WOG, September 2002, Vienna © Tom Mens, Vrije Universiteit Brussel 55

Wrap-up by Mehdi Jazayeri 56