code: public void setRepeatIntervalUnit (final EIntervalUnit intervalUnit)
    {
      if (m_eRepeatIntervalUnit == null ||
          !((m_eRepeatIntervalUnit.equals (EIntervalUnit.SECOND) ||
             m_eRepeatIntervalUnit.equals (EIntervalUnit.MINUTE) ||
             m_eRepeatIntervalUnit.equals (EIntervalUnit.HOUR))))
        throw new IllegalArgumentException ("Invalid repeat IntervalUnit (must be SECOND, MINUTE or HOUR).");
      m_eRepeatIntervalUnit = intervalUnit;
    }
docs: <p>
  Set the interval unit - the time unit on with the interval applies.
  </p>
  
  @param intervalUnit
  The repeat interval unit. The only intervals that are valid for this
  type of trigger are {@link EIntervalUnit#SECOND},
  {@link EIntervalUnit#MINUTE}, and {@link EIntervalUnit#HOUR}.