code: public String getField(String field) {
          HashMap map = fields;
          StringTokenizer tk = new StringTokenizer(field, ".");
          if (!tk.hasMoreTokens())
              return null;
          while (true) {
              String s = tk.nextToken();
              Object obj = map.get(s);
              if (obj == null)
                  return null;
              if (tk.hasMoreTokens()) {
                  if (obj instanceof HashMap)
                      map = (HashMap)obj;
                  else
                      return null;
              }
              else {
                  if (obj instanceof HashMap)
                      return null;
                  else {
                      if (((PdfObject)obj).isString())
                          return ((PdfString)obj).toUnicodeString();
                      else
                          return PdfName.decodeName(obj.toString());
                  }
              }
          }
      }
docs: Gets the field value.
  @param field the field name
  @return the field value or <CODE>null</CODE> if not found