Bug 53532

Description Michael D. Elder 2004-03-02 16:15:12 EST

We would like to request that
org.eclipse.ui.internal.registry.WizardsRegistryReader be made API (removed from
an internal package) and also that the Class Cast Exception which results
whenever you call findWizard(String id) be fixed. WizardsRegistryReader has only
one subclass in the base Platform,
org.eclipse.ui.internal.registry.NewWizardsRegistryReader, which overrides the
findWizard(String id), so it is not susceptible to the Class Cast Exception defect.

In our case, we are building a custom Navigator, and would like to provide ways
to re-use the Import/Export wizards specified through the standard Eclipse
extension points, but add these in a selective way to the context menus. If we
could re-use the above class (WizardsRegistryReader), it would provide a clean
implementation. We were able to do this with the NewWizardsRegistryReader. 

The problem we're running across is with the following method:

/**
 *	Returns the first wizard with a given id.
 */
public WorkbenchWizardElement findWizard(String id) {
	Object [] wizards = getWizardCollectionElements();
	for (int nX = 0; nX < wizards.length; nX ++) {
		WizardCollectionElement collection = (WizardCollectionElement)wizards[nX];
		WorkbenchWizardElement element = collection.findWizard(id,true);
		if (element != null)
			return element;
	}
	return null;
}

On "WizardCollectionElement collection = (WizardCollectionElement)wizards[nX];",
there is a Class Cast Exception because all of the elements in the array are
WorkbenchWizardElements. We corrected this in a subclass, by overriding the
method as follows:

	public WorkbenchWizardElement findWizard(String id) {
		if(id == null || id.length() == 0)
			return null;
		
		Object[] wizards = getWizardCollectionElements();
		for (int nX = 0; nX < wizards.length; nX++) {
//					WizardCollectionElement collection = (WizardCollectionElement) wizards[nX];
//					WorkbenchWizardElement element = collection.findWizard(id, true);
			WorkbenchWizardElement element = (WorkbenchWizardElement)wizards[nX];
			if(element != null && element.getID().equals(id)) 
				return element;
		}
		return null;
	}

Is there another way we should be reading these extension points? Any guidance
would be appreciated.  

Additionally, we would like to request a standard WizardShortcutAction like the
NewWizardShortcutAction. The NewWizardShortcutAction fails because it tries to
cast to INewWizard, which does not work (clearly) for Import/Export wizards.
Incidentally, changing the creation and cast of the INewWizard variable in the
NewWizardShortcutAction.run() to org.eclipse.ui.IWorkbenchWizard works fine, as
there are no actual dependencies on the INewWizard interface (given that the
interface defines no methods ;).