class ICalendarParser extends GenericMailet {

    @Override
    public void init() throws MessagingException {
        String sourceAttributeNameRaw = getInitParameter(SOURCE_ATTRIBUTE_PARAMETER_NAME, SOURCE_ATTRIBUTE_PARAMETER_DEFAULT_VALUE);
        if (Strings.isNullOrEmpty(sourceAttributeNameRaw)) {
            throw new MessagingException("source attribute cannot be empty");
        }
        sourceAttributeName = AttributeName.of(sourceAttributeNameRaw);

        String destinationAttributeNameRaw = getInitParameter(DESTINATION_ATTRIBUTE_PARAMETER_NAME, DESTINATION_ATTRIBUTE_PARAMETER_DEFAULT_VALUE);
        if (Strings.isNullOrEmpty(destinationAttributeNameRaw)) {
            throw new MessagingException("destination attribute cannot be empty");
        }
        destinationAttributeName = AttributeName.of(destinationAttributeNameRaw);
    }

}