List rejectedFolders= getFilteredExistingContainerEntries(); ViewerFilter filter= new TypedViewerFilter(acceptedClasses, rejectedFolders);
ViewerFilter filter= new TypedViewerFilter(acceptedClasses, getExistingContainers());
	private CPListElement[] chooseClassContainers() {			Class[] acceptedClasses= new Class[] { IFolder.class };		ISelectionValidator validator= new TypedElementSelectionValidator(acceptedClasses, true);					acceptedClasses= new Class[] { IProject.class, IFolder.class };				List rejectedFolders= getFilteredExistingContainerEntries();		ViewerFilter filter= new TypedViewerFilter(acceptedClasses, rejectedFolders);						ILabelProvider lp= new WorkbenchLabelProvider();		ITreeContentProvider cp= new WorkbenchContentProvider();		ElementTreeSelectionDialog dialog= new ElementTreeSelectionDialog(getShell(), lp, cp);		dialog.setValidator(validator);		dialog.setTitle(NewWizardMessages.getString("LibrariesWorkbookPage.ExistingClassFolderDialog.title")); //$NON-NLS-1$		dialog.setMessage(NewWizardMessages.getString("LibrariesWorkbookPage.ExistingClassFolderDialog.description")); //$NON-NLS-1$		dialog.addFilter(filter);				IProject proj= fCurrJProject.getProject();		if (dialog.open(fWorkspaceRoot, proj) == dialog.OK) {			Object[] elements= dialog.getResult();			CPListElement[] res= new CPListElement[elements.length];			for (int i= 0; i < res.length; i++) {				IResource elem= (IResource) elements[i];				res[i]= newCPLibraryElement(elem);			}			return res;		}		return null;			}