viewer.setContentProvider(new AdapterFactoryContentProvider(factory));
viewer.setLabelProvider(new AdapterFactoryLabelProvider(factory));

@Override
public ISelection getSelection() {
		
 IStructuredSelection selection = (IStructuredSelection)viewer.getSelection();
		
 if (selection.getFirstElement() == null)
   return StructuredSelection.EMPTY; 
		
 IItemPropertySource source = (IItemPropertySource)factory.adapt(selection.getFirstElement(), IItemPropertySource.class);
		
 return new StructuredSelection(new PropertySource(selection.getFirstElement(), source));
}

/**
* This is how the framework determines which interfaces we implement.
* <!-- begin-user-doc -->
* <!-- end-user-doc -->
* @generated
*/
@SuppressWarnings("rawtypes")
@Override
public Object getAdapter(Class key) {
  if (key.equals(IContentOutlinePage.class)) {
    return showOutlineView() ? getContentOutlinePage() : null;
  }
  else if (key.equals(IPropertySheetPage.class)) {
   return getPropertySheetPage();
  }
  else if (key.equals(IGotoMarker.class)) {
   return this;
  }
  else {
   return super.getAdapter(key);
  }
}