Der Mythos vom Re-Use

Transcription

1 Der Mythos vom Re-Use Was ist dran an der Wiederverwendung? Uwe Friedrichsen, codecentric GmbH SET 2009, Zürich, 5. Mai 2009

2 Uwe Friedrichsen Architect Consultant Project Manager Coach Software Architecture Enterprise Architecture Agility Manager Consulting codecentric GmbH 2

3 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 3

4 Reuse Promise Reality 4

5 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 5

6 Reasons for the Failure Corporate Organisation & Corporate Culture Fred Brooks Rule of 9 NIH-Syndrom (Not invented here) Efficiency of the Business Domain 6

7 Reuse Maturity Graph Business Domain Technical Concept Optimised Abstraction Level Business Service Technical Service Organisation Framework Collection Classes Code Ad hoc Coarse Granularity Fine Based on the Reuse Maturity Matrix, Don Kavanagh

8 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 8

9 Lifecycle of IT Systems Construction Phase Production & Maintenance Phase Begin of Lifecycle Go Live Source: Koskinen, J Software Maintenance Cost. End of Lifecycle 15% 85% 9

10 Potential of Reuse Scope of Reuse 10

11 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 11

12 The big Leverage Unused Potential 12

13 Design for Maintenance Design must serve Maintenance in the first Place and not Construction 13

14 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 14

15 Doing it wrong Dynamics of Change Demands of Construction 15

16 Doing it wrong Dynamics of Change Demands of Construction 16

17 Doing it wrong Dynamics of Change Demands of Construction 17

18 Doing it right Dynamics of Change Demands of Construction 18

19 Doing it right Dynamics of Change Demands of Construction 19

20 Doing it right Dynamics of Change Demands of Construction 20

21 Summary Doing it right & wrong Dynamics of Change Dynamics of Change Demands of Construction Demands of Construction Dynamics of Change Dynamics of Change Demands of Construction Demands of Construction 21

22 Reality is not two-dimensional Dynamics of Change Demands of Construction 22

23 Keep the Balance Dynamics of Change Demands of Construction 23

24 Implementation Hints Business first Observe the Flow of the Change Requests Loose Coupling starts at the Business Level Decouple Business and Technology Be careful with Layer Architecture Be careful with generic Solutions Verify your Architecture on a regular Basis 24

25 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 25

26 Use the Leverage of the Potential 26

27 Agenda Promise & Reality Why doesn t it work? Why doesn t it matter? What s the real Issue? What do we learn from it? How do I explain it to my Boss/Customer? Summary 27

28 Summary Reuse usually does not work as advertised The real Issue are the Maintenance Costs Design for Maintenance Dynamics of Change There is no Silver Bullet 28

29 Discussion Backup 29

30 Contact Uwe Friedrichsen Manager Consulting codecentric GmbH Merscheider Straße Solingen Germany Phone +49 (0) Fax +49 (0) Mobile +49 (0) friedrichsen@codecentric.de 30

31 Thanks for your Attention! codecentric GmbH Merscheider Straße Solingen Phone Fax info@codecentric.de 31