code: public void set(String name, Object obj) throws IOException {
          if (!(obj instanceof Date)) {
              throw new IOException("Attribute must be of type Date.");
          }
          if (name.equalsIgnoreCase(DATE)) {
              date = (Date) obj;
          } else {
              throw new IOException
                  ("Name not supported by InvalidityDateExtension");
          }
          encodeThis();
      }
docs: Set the attribute value.