This document discusses using Eclipse Equinox framework extensions to customize and integrate existing OSGi bundles at runtime without modifying their source code. It describes using XSLT transforms to modify plugin.xml definitions, and AspectJ weaving to suppress method calls or access internals. While this allows customizing bundles without access to their APIs, it breaks information hiding and relies on internal implementation details, requiring coping with changes across versions. The approach shifts responsibility from bundle vendors to those doing the integration work.

1. Runtime Surgery
New ways to integrate softwarecomponents
with eclipse equinox
Tobias Jenkner (edmPRO)

2. Surgery - who are the patients
●Eclipse Runtime – equinox
●Osgi: Reuse existing software
components
➔Patients: existing osgi bundles we want
to reuse

3. Reuse bundles: Customize
Plugin
to be reused
Java and OSGI
access restrictions
Initialization
Customize No public interface
Plugin
to be reused
Java and OSGI
access restrictions
Security

4. Reuse bundles: Separation of concerns
Client Common Server
Log API RCP ...
Menu-Entry Global UI
Software-Updates
Log impl RCP ...
Change Window View 1
Title
Log config RCP ...
RCP View 1 View 2

5. Summary:
Reuse bundles
✗ Separation of concerns
✗ Interfaces available
➔ Write a component once run everywhere
● Separation of concerns only in the context of
the original development (A single OSGI Bundle contains GUI,
configuration, business logic, …)
● Customization not possible (API not available)
● Write once break everywhere else

6. Integration – existing bundles

7. Integration options
●Enhancement request to the vendor / project
●Branch existing sourcecode
●Modify code at runtime with eclipse equinox
framework extensions

8. Eclipse equinox
Application of the patches at loadtime.
Eclipse Plugin
Equinox transforms xslt
● plugin.xml
Equinox weaving aspectj
● bytecode

9. Equinox transforms xslt
Change existing eclipse RCP extensions:
●Remove, relocate, restrict visibility of toolbar and
menu entries
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<!-- suppress the menuContribution for the command
org.eclipse.equinox.p2.ui.sdk.install -->
<xsl:template
match="extension[@point='org.eclipse.ui.menus']/
MenuContribution/
command[@commandId=
'org.eclipse.equinox.p2.ui.sdk.install']">
</xsl:template>
...

10. Equinox weaving aspectj
Use aspectj around advice to suppress method
calls
●Set window title
pointcut setTitle() :
call(void org.eclipse.swt.widgets.Shell.setText(String));
void around() : setTitle() {
// without proceed() - suppress the method call
}

11. Equinox weaving aspectj
●Access internals from existing bundles in order to
customize existing functionality
● AJDT, ScalaDT JDT
CompilationUnit around(PackageFragment parent, String name, WorkingCopyOwner owner) :
compilationUnitCreations(parent, name, owner) {
String newName = trimName(name);
String extension = findExtension(newName);
ICompilationUnitProvider provider =
CompilationUnitProviderRegistry.getInstance().getProvider(extension);
if (provider != null) {
try {
return provider.create(parent, newName, owner);
} catch (Throwable t) {
JDTWeavingPlugin.logException(t);
}
}
return proceed(parent, name, owner);
}
http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.ajdt/AJDT_src/org.eclipse.contribution.weaving.jdt/src/org/eclipse/contribution/jdt/cuprovider/CompilationUnitProviderAspect.aj?view=markup&root=Tools_Project

12. Use case summary
Weaving:
●Customize and extend existing functionality
(without API)
●Suppress method calls
Transforms:
●Cleanup Menus / UI
Both:
●Enforce integration specific coding
guidelines. Forbid usage of available APIs (e.g.
set window title).

13. Drawbacks
●Equinox waeving: Coping with internals /
breaking up information hiding
Doing the job of the vendor / project
●

14. Conclusion
Modify complete bundles at runtime:
●Declarative XML
●Java bytecode

15. What do you think?
● Useful ?
● Risk ?
● Production ?
● Responsibility ?
● ...