Presentation by Tim Ward (IBM) at OSGi DevCon/EclipseCon 2011. For many years bytecode weaving in OSGi has been a cumbersome process. Using it's internal hooks Equinox has supported basic transformation since version 3.2, but there has still been no simple, standard way to enhance classes or add new dependencies to the bundle that contains them. The Equinox 3.7 release includes support for the new OSGi WeavingHook whiteboard pattern, which allows any OSGi bundle, not just an Equinox framework extension, to weave classes from, and add dependencies to, other OSGi bundles. Also new in OSGi is the opportunity to scan the classpath of an OSGi bundle. Whilst the isolated, modular classpath of an OSGi bundle provides an excellent system for building Java applications, many extenders and libraries need to be able to search for classes or resources within the bundle. This function further aids weaving implementations by allowing them to search for resources, class and package name patterns, and other configuration without requiring specific metadata to be present. As the lead author for the Bytecode Weaving design within the OSGi Alliance, and a committer in the Apache Aries project, Tim will use his expertise to demonstrate the power and flexibility of WeavingHooks, particularly in conjunction with the latest OSGi updates for classpath scanning. Drawing on real-world examples from the Apache Aries project Tim will use real-world examples and Equinox 3.7 to prove that first-class weaving support is now available in OSGi

3. How weaving is done in Java SE (10,000 foot view)

4. Why OSGi needs a different approach

5. How to use OSGi weaving hooks

6. How to do classpath scanning in OSGi

7. A real world demo using classpath scanning and weaving

10. At packaging time

11. At class load time

15. In all cases we get an opportunity to read/change the bytes of the class file before they are loaded into the VM

18. New dependencies cannot be loaded without being imported by the bundle hosting the woven class

22. Read/Replace the class bytes that will be used

23. The BundleWiring and Bundle ClassLoader

24. A List of dynamic package imports to add, this allows us to add new dependencies based on what we weave!

28. filePattern lets you specify a type (e.g. *.class)

29. options lets you specify whether to recurse into sub-packages, and whether to include resources that are imported from other bundles

34. http://aries.apache.org/

35. Tim Ward:

36. @TimothyWard, [email_address]