Description Jean-Michel Lemieux 2005-05-30 09:13:06 EDT

3.1 RC1

I create a new plug-in without a bundle activator, then added a view that used
the Workbench's content and label providers. The applications model elements
extend PlatformObject thus inherits the getAdapter() method that looks via the
IAdapterManager for adapters. I added a couple of IWorkbenchAdapters to the
runtime.adapters extension point. When the application is run and getAdapter()
is called on the model elements the IAdapterManager returns that there are no
adapters registered. I looked into this and found that the following line was
causing the trouble:

AdapterFactoryProxy::loadFactory
String bundleId = element.getNamespace();
if (!force && Platform.getBundle(bundleId).getState() != Bundle.ACTIVE)
  return null;

This means that the adapter factory won't be visible until the plug-in that
defines it is loaded. This is probably the only place in the Platform were a
plug-in with an extension is not loaded when it's extension is needed. The
reason this isn't a problem for most is that if you define a bundle activator
PDE adds the EclipseAutoStart directory to the manifest, thus ensuring that the
plug-in is started.

I'm not sure what the solution should be but here are some general observations:

1. PlatformObject calls IAdapterManager.getAdapter() which won't lazily load. A
Workaround is to not extend PlatformObject and instead implement my own
getAdapter() using IAdapterManager.loadAdapter() instead. This forces plug-in
activation.

2. But this begs the question, shouldn't PlatformObject just call loadAdapter()
and force the callers to decide if they don't want to load plug-ins? I get that
in most cases you *want* to load the adapter factory, and the only cases where
you don't (e.g. in the Workbench contribution code) it is calling
IAdapterManager.getAdapter() explicitly anyway.