code: public synchronized TemporalDocument next() {
  	
  	int firstSpace = nextLine.indexOf(" ");
  	String timeStr = nextLine.substring(0, firstSpace);
  	String doc = nextLine.substring(firstSpace);
  	TemporalDocument next = 
  	    new TemporalStringDocument(doc, Long.parseLong(timeStr));
  	try {
  	    nextLine = documentsReader.readLine();
  	} catch (Throwable t) {
  	    t.printStackTrace();
  	    nextLine = null;
  	}
  	return next;
      }
docs: Returns the next document from the file.