Search Digital Signature in POTX via Java

Signature signature = new Signature("signed.pdf");
DigitalSearchOptions options = new DigitalSearchOptions();
// specify special search criteria
options.setComments("Test comment");
// certificate issues criteria
options.setIssuerName("John");
// digital certificate subject
options.setSubjectName("Test");
// specify date range period of signature
options.setSignDateTimeFrom(DateUtils.addMonths(new Date(), -1));
options.setSignDateTimeTo(new Date());
 
// search for signatures in document
List signatures = signature.search(DigitalSignature.class, options);
System.out.print("\nSource document contains following signatures.");
for (DigitalSignature digitalSignature : signatures)
{
    System.out.print("Digital signature found from "+digitalSignature.getSignTime()+" with validation flag "+digitalSignature.isValid()+". Certificate SN "+ digitalSignature.getCertificate().getType());
}