Equinox Weaving QuickStart

This page replaces the out-of-date "Equinox Aspects Quick-Start Guide"

Enabling Weaving for Plug-Ins with AspectJ

As of Eclipse Juno, these are the steps required to enable Equinox Weaving with AspectJ. Note that the aop.xml file is no longer necessary.

• Install the AspectJ Development Tooling (AJDT) and Equinox Weaving from the AJDT Downloads.
• Define your aspect(s) in a bundle.
• Configure your bundle's MANIFEST.MF to (i) export its aspects, and (ii) specify the bundles that its aspects advise. The former is done by adding a parameter on the Export-Package header. The latter is done through the Eclipse-SupplementBundle header. For example, a bundle with an aspect swing.edt.EdtRuleChecker, advising bundles com.example.core and com.example.ui would specify:

Export-Package: swing.edt;aspects="EdtRuleChecker"
Eclipse-SupplementBundle: com.example.core, com.example.ui

• Add the following bundles to your launch configuration
  • org.aspectj.weaver
  • org.eclipse.equinox.weaving.aspectj
  • org.eclipse.equinox.weaving.caching
  • org.eclipse.equinox.weaving.hook
• Ensure org.eclipse.equinox.weaving.aspectj is auto-started at, say, level 2
• Add the following VM argument (or to your config.ini) to instruct OSGi to load the weaving hooks:

-Dosgi.framework.extensions=org.eclipse.equinox.weaving.hook

Control How Aspects are Applied with 'aspect-policy'

Aspects can be defined as opt-in (bundles have to explicitly ask for the aspects to be installed) or opt-out (bundles must explicitly opt-out from weaving). Opt-out is the default policy. For example, to change the policy to opt-in:

Export-Package: swing.debug; aspects="EdtRuleChecker"; aspect-policy:=opt-in

Control How Aspects are Received with 'apply-aspects'

A bundle can explicitly request or forbid aspects being applied to it through the apply-aspects parameter on Import-Package:

Import-Package: swing.debug; apply-aspects:=false

apply-aspects defaults to true, indicating that aspects should be woven into the bundle, whereas false indicates that aspects should not be applied. These parameters override the supplying bundle's aspect-policy.

The Eclipse-BundleSupplement in effect causes the specified bundles to include Import-Package: ...; apply-aspects:=true for the packages that are exported by the aspects bundle.

Debugging

For debugging output, add the following VM arguments:

-Daj.weaving.verbose=true
-Dorg.aspectj.weaver.showWeaveInfo=true
-Dorg.aspectj.osgi.verbose=true

The org.eclipse.osgi and org.eclipse.equinox.weaving bundles must be in the same physical directories on disk. So, you cannot use multiple installation locations for these bundles and if one bundle is checked out as source, then so must the other.

Sources

• Martin Lippert (2009). What's New in Equinox Aspects. JAX 2009
• James Sugrue (2010). Aspect Oriented Programming for Eclipse Plug-ins. dZone.
• JDT Weaving Features