class TagHelper {

    public void validateTagKey(TagKey tagKey) throws IllegalArgumentException
    {
        Assert.notNull(tagKey, "A tag key must be specified.");
        tagKey.setTagTypeCode(alternateKeyHelper.validateStringParameter("tag type code", tagKey.getTagTypeCode()));
        tagKey.setTagCode(alternateKeyHelper.validateStringParameter("tag code", tagKey.getTagCode()));
    }

}