title: Checking timestamp with iText 2.1.7
body: <p>I am trying to check the existence of timestamp for a given signature of a PDF file.
  So far I came to this code:</p>
  
  <pre><code>RandomAccessFileOrArray random = 
      new RandomAccessFileOrArray(new File("temp.pdf").getAbsolutePath());
  
  PdfReader reader = new PdfReader(random, null);
  AcroFields af = reader.getAcroFields();
  ArrayList&lt;?&gt; names = af.getSignatureNames();
  
  //this are the signatures?
  for (Object o : names){
  
      AcroFields.Item item = (Item) af.getFields().get((String)o);
  
      //this is the class for verifying the signature, 
      //how do I get it from the item?
      PdfPKCS7 pdfPKCS7 = null; //XYZ ??? 
  
      Calendar signingDate = pdfPKCS7.getTimeStampDate();
  }
  </code></pre>
  
  <p>I apparently got access to the signature, but I should get to PdfPKCS7 class for verifying the signature. Does anyone have any idea how can I get there? </p>