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How to manage software complexity with OSGi

Peter Kriens
Peter Kriens

The document discusses managing software complexity with OSGi. It defines complexity as the energy required to complete a task. Modularity reduces complexity by limiting interdependence between modules. OSGi addresses issues like class loading and dependency hell that emerge from tightly coupled systems. Tools are needed to manage metadata and dependencies in OSGi environments. Overall, OSGi promotes a microservices architecture and incremental development to reduce complexity.

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How to Manage Software Complexity with OSGi Peter Kriens & David Savage donderdag 24 maart 2011
What is Complexity? donderdag 24 maart 2011
Complex? donderdag 24 maart 2011
The puzzle looks very simple, contrary to many other wire puzzles, that look scary and complex right from the start. Nevertheless, its looks are deceiving, as it can prove to be frustratingly dif鍖cult to solve. donderdag 24 maart 2011
Complex? donderdag 24 maart 2011
Complex? Worlds Largest Jigsaw Puzzle 24.000 pieces (4.28m x 1.57m) donderdag 24 maart 2011
The Eye Of The Beholder Complexity of a task is the energy you use to complete that task c = E/m donderdag 24 maart 2011
The Eye Of The Beholder Complexity of a task is the energy you use to complete that task c = E/m donderdag 24 maart 2011
Energy? Understanding the problem Learning the solution Accidental complexity Size matters! donderdag 24 maart 2011
Energy? Subjective Complexity Understanding the problem Learning the solution Accidental complexity Size matters! donderdag 24 maart 2011
Energy? Subjective Complexity Understanding the problem Learning the solution Accidental complexity Size matters! Absolute Complexity size related donderdag 24 maart 2011
Whats Modularity Got to do With Size??? donderdag 24 maart 2011
Modularity Functions local variables Object Oriented fields, methods, inheritance, polymorphism instances Bundles implementations, services components donderdag 24 maart 2011
Modularity Functions local variables Object Oriented fields, methods, inheritance, polymorphism instances Bundles implementations, services components donderdag 24 maart 2011
Modularity Modularity is about creating a difference between an inside and an A B outside AB CD Chunking - having an anchor for an aggregation C D Visibility - is reduced, reducing the scope to attend for changes donderdag 24 maart 2011
Modularity Modularity is about creating a difference between an inside and an A B outside Chunking - having an anchor for an aggregation C AB CD D Visibility - is reduced, reducing the scope to attend for changes donderdag 24 maart 2011
Modularity modules have a private space and share a public space A B modules limit their visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
Modularity modules have a private space and share a public space A B modules limit their Pub visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
Modularity modules have a private space and share a public space A B modules limit their Pub visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
Entropy E functionality Emodularization donderdag 24 maart 2011
#1 OSGi Complaint: Class Loaders! donderdag 24 maart 2011
Classloaders & Modularity donderdag 24 maart 2011
Class Loading Revisited Class.forName Class path Scanning Service Loader Thread Context Class Loaders Factory, and FactoryBuilders donderdag 24 maart 2011
Class Loading Revisited Class loaders are used to provide extensibility and decoupling A B They were not Pub designed for this purpose, C D And class loaders break module boundaries donderdag 24 maart 2011
Class Loading Revisited A B Public donderdag 24 maart 2011
Class Loading Revisited A B C Public donderdag 24 maart 2011
Class Loading Revisited A B C I Public donderdag 24 maart 2011
Class Loading Revisited A B C X I Public donderdag 24 maart 2011
Class Loading Revisited A B C P I Public donderdag 24 maart 2011
Would be nice to mention how 袖Services reduce surface area of design 袖Services efficiency of packet based approaches? but cost of packet based system is congestion - leads into dependency hell? donderdag 24 maart 2011
#2 OSGi Complaint: Dependency Hell donderdag 24 maart 2011
Metadata Hell? donderdag 24 maart 2011
Transitive Hell? donderdag 24 maart 2011
Coupling Modules require other modules Dependencies are A B transitive Pub ACD C D donderdag 24 maart 2011
Coupling Modules require other modules Dependencies are A B transitive Pub ACD C D donderdag 24 maart 2011
Cohesion Fan out is a problem A does not transitively depend on D! A B The dependency is caused by C D (unnecessarily) packing 1 and 2 in the same module donderdag 24 maart 2011
Cohesion Fan out is a problem A does not transitively depend on D! A A B The dependency is caused by 1 2 D (unnecessarily) packing C 1 and 2 in the same module donderdag 24 maart 2011
Cohesion Refactoring can increase the cohesion and reduce coupling A B But now A depends on C1 and B depends on C2 C 1 C 2 D Package dependencies C are more robust to changes donderdag 24 maart 2011
Cohesion Refactoring can increase the cohesion and reduce coupling A B But now A depends on C1 and B depends on C2 C 1 C 2 D Package dependencies are more robust to changes donderdag 24 maart 2011
Metadata Heaven? donderdag 24 maart 2011
Requires Tools donderdag 24 maart 2011
Tools 1 Request deployment of a component, e.g. a Bundle, WAR, WAB or EAR 2 Refer to Application Policy Resolver App Policy 3 Resolve Dependencies 4 Provision according to component and Policy dependencies Repository Nimble donderdag 24 maart 2011
Tools 1 Request deployment of a component, e.g. a Bundle, WAR, WAB or EAR 2 Refer to Application Policy Resolver App Policy 3 Resolve Dependencies 4 Provision according to component and Policy dependencies Repository Nimble donderdag 24 maart 2011
OSGi OSGi OSGi Build Tools Runtime Tools Cloud Tools ... donderdag 24 maart 2011
OSGi OSGi OSGi Build Tools Runtime Tools Cloud Tools ... donderdag 24 maart 2011
How to Manage Complexity? Prepare to spend energy! Architecture = 袖service model Use tools to manage Metadata and Dependencies Small increments One test is worth a thousand opinions. donderdag 24 maart 2011

More Related Content

How to manage software complexity with OSGi

  • 1. How to Manage Software Complexity with OSGi Peter Kriens & David Savage donderdag 24 maart 2011
  • 4. The puzzle looks very simple, contrary to many other wire puzzles, that look scary and complex right from the start. Nevertheless, its looks are deceiving, as it can prove to be frustratingly dif鍖cult to solve. donderdag 24 maart 2011
  • 6. Complex? Worlds Largest Jigsaw Puzzle 24.000 pieces (4.28m x 1.57m) donderdag 24 maart 2011
  • 7. The Eye Of The Beholder Complexity of a task is the energy you use to complete that task c = E/m donderdag 24 maart 2011
  • 8. The Eye Of The Beholder Complexity of a task is the energy you use to complete that task c = E/m donderdag 24 maart 2011
  • 9. Energy? Understanding the problem Learning the solution Accidental complexity Size matters! donderdag 24 maart 2011
  • 10. Energy? Subjective Complexity Understanding the problem Learning the solution Accidental complexity Size matters! donderdag 24 maart 2011
  • 11. Energy? Subjective Complexity Understanding the problem Learning the solution Accidental complexity Size matters! Absolute Complexity size related donderdag 24 maart 2011
  • 12. Whats Modularity Got to do With Size??? donderdag 24 maart 2011
  • 13. Modularity Functions local variables Object Oriented fields, methods, inheritance, polymorphism instances Bundles implementations, services components donderdag 24 maart 2011
  • 14. Modularity Functions local variables Object Oriented fields, methods, inheritance, polymorphism instances Bundles implementations, services components donderdag 24 maart 2011
  • 15. Modularity Modularity is about creating a difference between an inside and an A B outside AB CD Chunking - having an anchor for an aggregation C D Visibility - is reduced, reducing the scope to attend for changes donderdag 24 maart 2011
  • 16. Modularity Modularity is about creating a difference between an inside and an A B outside Chunking - having an anchor for an aggregation C AB CD D Visibility - is reduced, reducing the scope to attend for changes donderdag 24 maart 2011
  • 17. Modularity modules have a private space and share a public space A B modules limit their visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
  • 18. Modularity modules have a private space and share a public space A B modules limit their Pub visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
  • 19. Modularity modules have a private space and share a public space A B modules limit their Pub visibility and exposure C D Reduces geometric to linear complexity donderdag 24 maart 2011
  • 20. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 21. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 22. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 23. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 24. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 25. Entropy E functionality Emodularization donderdag 24 maart 2011
  • 26. #1 OSGi Complaint: Class Loaders! donderdag 24 maart 2011
  • 28. Class Loading Revisited Class.forName Class path Scanning Service Loader Thread Context Class Loaders Factory, and FactoryBuilders donderdag 24 maart 2011
  • 29. Class Loading Revisited Class loaders are used to provide extensibility and decoupling A B They were not Pub designed for this purpose, C D And class loaders break module boundaries donderdag 24 maart 2011
  • 30. Class Loading Revisited A B Public donderdag 24 maart 2011
  • 31. Class Loading Revisited A B C Public donderdag 24 maart 2011
  • 32. Class Loading Revisited A B C I Public donderdag 24 maart 2011
  • 33. Class Loading Revisited A B C X I Public donderdag 24 maart 2011
  • 34. Class Loading Revisited A B C P I Public donderdag 24 maart 2011
  • 35. Would be nice to mention how 袖Services reduce surface area of design 袖Services efficiency of packet based approaches? but cost of packet based system is congestion - leads into dependency hell? donderdag 24 maart 2011
  • 36. #2 OSGi Complaint: Dependency Hell donderdag 24 maart 2011
  • 39. Coupling Modules require other modules Dependencies are A B transitive Pub ACD C D donderdag 24 maart 2011
  • 40. Coupling Modules require other modules Dependencies are A B transitive Pub ACD C D donderdag 24 maart 2011
  • 41. Cohesion Fan out is a problem A does not transitively depend on D! A B The dependency is caused by C D (unnecessarily) packing 1 and 2 in the same module donderdag 24 maart 2011
  • 42. Cohesion Fan out is a problem A does not transitively depend on D! A A B The dependency is caused by 1 2 D (unnecessarily) packing C 1 and 2 in the same module donderdag 24 maart 2011
  • 43. Cohesion Refactoring can increase the cohesion and reduce coupling A B But now A depends on C1 and B depends on C2 C 1 C 2 D Package dependencies C are more robust to changes donderdag 24 maart 2011
  • 44. Cohesion Refactoring can increase the cohesion and reduce coupling A B But now A depends on C1 and B depends on C2 C 1 C 2 D Package dependencies are more robust to changes donderdag 24 maart 2011
  • 47. Tools 1 Request deployment of a component, e.g. a Bundle, WAR, WAB or EAR 2 Refer to Application Policy Resolver App Policy 3 Resolve Dependencies 4 Provision according to component and Policy dependencies Repository Nimble donderdag 24 maart 2011
  • 48. Tools 1 Request deployment of a component, e.g. a Bundle, WAR, WAB or EAR 2 Refer to Application Policy Resolver App Policy 3 Resolve Dependencies 4 Provision according to component and Policy dependencies Repository Nimble donderdag 24 maart 2011
  • 49. OSGi OSGi OSGi Build Tools Runtime Tools Cloud Tools ... donderdag 24 maart 2011
  • 50. OSGi OSGi OSGi Build Tools Runtime Tools Cloud Tools ... donderdag 24 maart 2011
  • 51. How to Manage Complexity? Prepare to spend energy! Architecture = 袖service model Use tools to manage Metadata and Dependencies Small increments One test is worth a thousand opinions. donderdag 24 maart 2011