1. Eclipse as a framework of frameworks (Please view in presentation mode for desired flow of information) Anshu Jain IBM Research - India [email_address] anshunjain {gmail, twitter, googlesites)

5. What are we doing today Building a VERY simple calculator

6. V1 - Monolithic Class

9. The only constant - Change 1. Add new features – New functions 2. Fix existing features – Divide by Zero

10. The only constant – Change..!! private void addFunctions(Composite functionComposite) { … … Button xpoweryButton = new Button(functionComposite, SWT. NONE ); xpoweryButton.addSelectionListener( new ButtonSelectionListener( "+" )); xpoweryButton.setLayoutData(data); xpoweryButton.setText( "x^y" ); Button modButton = new Button(functionComposite, SWT. NONE ); addButton.addSelectionListener( new ButtonSelectionListener( "Mod" )); modButton.setLayoutData(data); modButton.setText( "Mod" ); private int divide( int a, int b) { if (b == 0) { text .setText( "DivideBy0 Error!" ); return -1; } else { if (a % b == 0) { text .setText( "Not absolute" ); return a % b; } return a / b; } }

13. V2 Refactoring – Separation of concern

14. V2 Refactoring – Separation of Concern Encapsulation

16. V3 – Thought ful Refactoring We still need to reference each function in calculator Code of createButton is common

17. V4 - Thoughtful Inheritance

20. Where to look for Any folder in my working directory becomes a function

21. Where to look for Nah..!! Not any folder..!!

22. V5 - Identification

24. V5 – Dynamic Runtime - Dynamic loading of this jar (Classloading) - Dynamic instantiation of this class(Reflection)

25. V6 - Dynamic Discovery and Loading public void load(Calculator_Original calculator, String installDirectory) throws InstantiationException, IllegalAccessException { try { String[] nameOfFunctions = loadFunctionsFromDirectory(installDirectory); IFunction[] functions = new IFunction[nameOfFunctions. length ]; MyCustomClassLoader loader = new MyCustomClassLoader( installDirectory); for (IFunction function : functions) { Class functionClass = loader.loadClass( "" ); function = (IFunction) functionClass.newInstance(); function.setCalculator(calculator); } } catch (ClassNotFoundException e) { // Handle this } }

28. Revisiting our framework Separation of Concern Componentization Abstraction/Interface Registration and Discovery Dynamic Loading

35. Component Model - Identification - add.cff - add.jar - Component Identifier - Component runtime info

36. Component Model - Identification BUNDLES - Manifest.MF - <bundlename>.jar - Bundle ID - Runtime Info: Classpath - blah..blah..

38. Component Model – Other APIs Framework for observing other components and services Resource and class loading Dynamic management of dependencies Hooks to component lifecycle Service oriented component management

40. Framework for discovery Who wants to let others extend them? Who wants to extend? Who is extending me? Configuration provided by the extenders Properties of extenders I am lazy to even load the runtime Dynamic management of extenders

45. Thank you