}
            return value.toString();
        }

        /**
         * Gets the source index.
         *
         * @return the source index
         */
        public int getIndex() {
            return index;
        }

        /**
         * Sets the source index.
         *
         * @param index the source index
         */
        public void setIndex(final int index) {

    assertTrue(interfaces.hasMoreElements());
    while (interfaces.hasMoreElements()) {
      NetworkInterface i = interfaces.nextElement();
      builder.add(i.getName()).add(String.valueOf(i.getIndex()));
    }
    return builder.build();
  }

  /** Checks that the IP converts to the big integer and the big integer converts to the IP. */