code: public static long checkInvariantL(
      final long value,
      final ContractLongConditionType condition)
      throws InvariantViolationException
    {
      return checkInvariantL(value, condition.predicate(), condition.describer());
    }
docs: A {@code long} specialized version of {@link #checkInvariant(Object,
  ContractConditionType)}.
  
  @param value     The value
  @param condition The predicate
  
  @return value
  
  @throws InvariantViolationException If the predicate is false