return createStructureComparator(input, buffer, doc, null);
return createStructureComparator(input, buffer, doc, null, null);
	public IStructureComparator getStructure(final Object input) {		String contents= null;		char[] buffer= null;		IDocument doc= CompareUI.getDocument(input);		if (doc == null) {			if (input instanceof IStreamContentAccessor) {				IStreamContentAccessor sca= (IStreamContentAccessor) input;							try {					contents= JavaCompareUtilities.readString(sca);				} catch (CoreException ex) {					// return null indicates the error.					return null;				}						}						if (contents != null) {				int n= contents.length();				buffer= new char[n];				contents.getChars(0, n, buffer, 0);								doc= new Document(contents);				setupDocument(doc);							}		}				return createStructureComparator(input, buffer, doc, null);	}