//open input stream to file
File file = (File)iv_files.get(iv_currentIndex);
fileInputStream = new FileInputStream(file);
fileReader = new BufferedReader(new InputStreamReader(fileInputStream));
DocumentID documentIDAnnotation = new DocumentID(jcas);
String docID = createDocID(file);
documentIDAnnotation.setDocumentID(docID);
documentIDAnnotation.addToIndexes();
//if there's a CAS Initializer, call it
if (getCasInitializer() != null)
{
getCasInitializer().initializeCas(fileReader, aCAS);