Re: [equinox-dev] Re: Embedding Equinox OSGi and EclipseStarter

[Thomas Watson <tjwatson@xxxxxxxxxx>]

> In that document, in the section "The Hook
Registry", we find this
> paragraph:
> 
> ,----[  hookconfigurators.properties files ]
> | Extension bundles may provide their own hookconfigurators.properties
> | file to specify additional hook configurators. The hook registry
will
> | discover all hookconfigurator.properties files on its classpath
and
> | will merge all declared configurator classes into one list.
> `----
> 
> Note the phrase "on /its/ classpath". What is /it/ here?

Here /it/ means the classpath of the framework implementation.

> 
> I ask because I created an extension bundle with a
> hookconfigurator.properties file as specified, located at the root
> directory within the extension bundle jar. The extension bundle gets
> loaded just fine, but it doesn't look like the bundle gets searched
by
> HookRegistry.mergeFileHookConfigurators()¹. My bundle's
> hookconfigurators.properties files is never found, and hence my hook
> doesn't get registered.
> 
> Should I be able to provide a hookconfigurators.properties file in
my
> extension bundle? If so, what do I have to do make it discoverable?
> 
> 
> Footnotes: 
> ¹ On line 108, where ClassLoader.getResources() is called.

There is a chicken and egg issue here when loading
hook configurators.
In order to get your hook configurator loaded your
framework extension
bundle must be on the framework's classpath before
the framework is 
launched.  In a typical eclipse environement
this is done by the 
org.eclipse.equinox.launcher (or startup.jar in <=
3.2.x).  The 
launcher reads the "osgi.framework.extensions"
property and discovers 
the extensions listed in that property.  These
extension jars must be
colocated with the org.eclipse.osgi jar.  If
you do not do this then
the extension jar will get loaded after all the hook
configurators have
run.  At this point it is too late.

If you are not using the equinox launcher to start
the Framework then 
you will have to add your extension jars to the classpath
along 
with the org.eclipse.osgi when you are launching the
Framework.

Tom