class AcroFields {

    public boolean signatureCoversWholeDocument(String name) {
        getSignatureNames();
        name = getTranslatedFieldName(name);
        if (!sigNames.containsKey(name))
            return false;
        try {
            ContentsChecker signatureReader = new ContentsChecker(reader.getSafeFile());
            return signatureReader.checkWhetherSignatureCoversWholeDocument(reader.getAcroFields().getFieldItem(name));
        } catch (IOException e) {
            // That's not expected because if the signature is invalid, it should have already failed
            return false;
        }
    }

      AcroFields(PdfReader reader, PdfWriter writer);

}