Many services in JViews need
to look up a resource. Since the classical way to provide access to
resources is a class loader, JViews uses
class loaders for this purpose. But in Eclipse/RCP applications, each
plug-in corresponds to a class loader, and the JViews class loader sees only its own resources, not
the application resources. To fix this problem, you can register plug-in
class loaders with JViews through
the IlvClassLoaderUtil.registerClassLoader function.
Each resource lookup then considers the registered class loaders and,
if the plug-ins are configured accordingly, also considers the dependencies
of the registered class loaders.
The code for doing this is usually located in a plug-in
activator class. For example:
public class MyPluginActivator extends AbstractUIPlugin
{
/**
* This method is called upon plugin activation
*/
public void start(BundleContext context) throws Exception {
super.start(context);
IlvClassLoaderUtil.registerClassLoader(getClass().getClassLoader());
}
/**
* This method is called when the plugin is stopped
*/
public void stop(BundleContext context) throws Exception {
super.stop(context);
IlvClassLoaderUtil.unregisterClassLoader(getClass().getClassLoader());
}
}
The overriding of stop() is
necessary so that, when the plug-in gets unloaded, JViews gets notified
about the plug-in that is going to stop and can drop references to
its resources or instances of its classes. The activator plug-in
is usually also the place where IlvProductUtil.registerApplication is
called.