List rejectedElements= getFilteredExistingContainerEntries(); ViewerFilter filter= new TypedViewerFilter(acceptedClasses, rejectedElements);
ViewerFilter filter= new TypedViewerFilter(acceptedClasses, getExistingContainers());
	private CPListElement[] chooseSourceContainers() {			Class[] acceptedClasses= new Class[] { IFolder.class };		ISelectionValidator validator= new TypedElementSelectionValidator(acceptedClasses, true);					acceptedClasses= new Class[] { IFolder.class };		List rejectedElements= getFilteredExistingContainerEntries();		ViewerFilter filter= new TypedViewerFilter(acceptedClasses, rejectedElements);					ILabelProvider lp= new WorkbenchLabelProvider();		ITreeContentProvider cp= new WorkbenchContentProvider();		ElementTreeSelectionDialog dialog= new ElementTreeSelectionDialog(fShell, lp, cp);		dialog.setValidator(validator);		dialog.setTitle(NewWizardMessages.getString("SourceContainerWorkbookPage.ExistingSourceFolderDialog.title")); //$NON-NLS-1$		dialog.setMessage(NewWizardMessages.getString("SourceContainerWorkbookPage.ExistingSourceFolderDialog.description")); //$NON-NLS-1$		dialog.addFilter(filter);				IProject proj= fCurrJProject.getProject();		if (dialog.open(proj, null) == 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]= newCPSourceElement(elem);			}			return res;		}		return null;			}