public int setCurrentPagePrevious() {
        int decrement = 0;
        if (documentViewModel != null) {
            decrement = documentView.getPreviousPageIncrement();
            int current = documentViewModel.getViewCurrentPageIndex();
            if ((current - decrement) >= 0) {
                documentViewModel.setViewCurrentPageIndex(current - decrement);
            } else {
                documentViewModel.setViewCurrentPageIndex(0);
            }
        }
        return decrement;
    }