return null;
return DocumentAdapter.NULL;
			public IBuffer createBuffer(IOpenable owner) {				if (owner instanceof ICompilationUnit) {										ICompilationUnit unit= (ICompilationUnit) owner;										try {												ICompilationUnit original= (ICompilationUnit) unit.getOriginalElement();						IResource resource= original.getCorrespondingResource();						if (resource instanceof IFile) {							IFileEditorInput providerKey= new FileEditorInput((IFile) resource);							IDocument document= internalGetDocument(providerKey);							return new DocumentAdapter(unit, document, new DefaultLineTracker(), CompilationUnitDocumentProvider.this, providerKey);						}											} catch (CoreException x) {						handleCoreException(x, JavaUIMessages.getString("CompilationUnitDocumentProvider.problemsCreatingBuffer")); //$NON-NLS-1$					}				}				return null;			}