W-JAX 08 - Aspect Weaving for OSGii

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W-JAX 08 - Aspect Weaving for OSGii

  1. 1. Aspect Weaving for OSGi Martin Lippert (akquinet it-agile GmbH) Heiko Seeberger (Weigle Wil H ik S b (W i l Wilczek G bH) k GmbH) © 2008 by Martin Lippert, Heiko Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license | November 7th, 2008
  2. 2. Aspect-oriented programming • Modularity improved a lot by OO concepts Classes, interfaces Information hiding, polymorphism, inheritance • AOP adds additional concepts To modularize so called “cross-cutting concerns” ClassA ClassB ClassC AspectX ConcernX ConcernX ConcernX ConcernX Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  3. 3. AOP today • Meanwhile AOP is an established concept Useful for many situations Mostly technology-centric usage scenarios • Established languages and frameworks available AspectJ: powerful language extension to Java Spring-AOP: Spring AOP: simple to use AOP for enterprise apps • Used in production: Spring itself makes heavy use of AOP concepts App-servers are using AOP inside Direct AOP selectively used in enterprise apps Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  4. 4. AspectJ = AOP for Java • AspectJ is a powerful language extension for Java Hosted as an Eclipse project Still very active (latest release 1.6.1 in July 2008) • AJDT: Great tooling for the Eclipse IDE (3.3, 3.4) Comes close to the JDT feeling • Spring-IDE: Integrates AJDT with Spring-AOP AJDT feeling for Spring apps Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  5. 5. The Standard Use Case ClassA ClassB ClassC AspectX ConcernX ConcernX ConcernX ConcernX Project Sources Single Application Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  6. 6. Library Aspects ClassA ClassB ClassC AspectX ConcernX ConcernX ConcernX ConcernX Project Sources JAR Single Application Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  7. 7. Aspects for Existing Code ClassA ClassB ClassC AspectX ConcernX ConcernX ConcernX ConcernX JARs Project Sources Single Application Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  8. 8. Java + OSGi • OSGi: “A dynamic module system for Java” • Modularity • Dynamic • Service-Oriented Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  9. 9. What does it mean for us? • We would like to modularize … classes and interfaces into bundles … and aspects into bundles • The obvious next step: modularize cross cutting concerns into bundles cross-cutting • Takes modularity to the next level Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  10. 10. Intra-Bundle Aspects ClassA ClassB ClassC AspectX ConcernX ConcernX Bundle A Bundle B Bundle-Classpath Bundle-Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  11. 11. Co-Op Bundle Aspects ClassA ClassB ClassC AspectX ConcernX ConcernX ConcernX ConcernX Bundle A Bundle B Bundle C Bundle-Classpath Bundle-Classpath Bundle-Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  12. 12. Abstract Aspect Bundles ClassA ClassB Abstract Ab t t Concrete C t Aspect Aspect ConcernX ConcernX ConcernX ConcernX Bundle A Bundle B Bundle-Classpath Bundle-Classpath Java Virtual Machine Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  13. 13. Dynamics for Aspect Bundles • OSGi allows dynamic bundle … installs … uninstalls … updates • Same should be possible for aspect bundles … dynamic installs, uninstalls and updates of aspect bundles … dynamic installs, uninstalls and updates of bundles that are affected by aspects ff t d b t Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  14. 14. How could all this possibly work? Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  15. 15. Equinox Aspects • Equinox Incubator Project http://www.eclipse.org/equinox/incubator/aspects • Enables AspectJ/AOP for OSGi Supports all presented use-cases Ready-to-use Ready to use • Setting Works with Eclipse 3.4 (and 3.3 deprecated) Works with AJDT 1.5.2, 1.5.3, 1.6.0, 1.6.1 Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  16. 16. What can I do? • Put aspects into standard OSGi bundles Just like Java classes • Define what and where to weave aop.xml and manifest headers • Go! • Feels like a natural combination of AOP and OSGi OSGi… Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  17. 17. Load-Time Weaving for OSGi • Let the OSGi runtime take care of weaving the aspects (and not the compiler) Leads to load-time weaving within OSGi • This means: No recompilation of existing bundles necessary Supports “aop.xml” load-time weaving config of AspectJ Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  18. 18. Live Demo • Monitoring Eclipse bundles bundles… Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  19. 19. Caching • Wasn’t that a fast startup? Wasn t • The reason: caching for woven classes Load-time weaving happens only once Second time startup is same as without aspects Available for t d d JREs d A il bl f standard JRE and IBM J9 shared classes h dl Supports configuration switching Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  20. 20. Dynamics • Dynamics for aspect bundles Means re- or un-weaving existing bundles • How is it realized? Silent update of bundles to be woven again Bundles must behave nicely within dynamic situations Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  21. 21. Live Demo • Installing Installing, updating, uninstalling aspects at runtime… Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  22. 22. AOP in Spring • Spring uses AOP a lot for all kinds of purposes • @Configurable is one example • Realized by Spring via load-time aspect weaving Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  23. 23. Spring & Equinox Aspects • Equinox Aspects can do load time aspect weaving for load-time Spring-powered bundles… • Live Demo @Configurable for Extensions (Views in Eclipse RCP apps) Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  24. 24. APIs and Implementation • org eclipse equinox weaving hook org.eclipse.equinox.weaving.hook Hooks into the runtime Provides API for injecting weaving and caching implementations • org.eclipse.equinox.weaving.aspectj Implements aspect weaving using AspectJ • org.eclipse.equinox.weaving.caching Implements caching for standard VMs • org.eclipse.equinox.weaving.caching.j9 Implements caching for IBM J9 VMs (shared classes feature) Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  25. 25. Conclusions • Equinox Aspects brings full AOP to OSGi Load-time weaving integrated into OSGi Combines OSGi and AOP modularity features • Can be used for production systems today • Give it a try http://www.eclipse.org/equinox/incubator/aspects Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license
  26. 26. Thank you for your attention! Q&A Heiko Seeberger: seeberger@weiglewilczek.com Martin Lippert lippert@acm org Lippert: lippert@acm.org Aspect Weaving for OSGi | © 2008 by M. Lippert, H. Seeberger; made available under Creative Commons Att. Nc Nd 2.5 license

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