*
     * @param source the source encoding name
     * @param target the target encoding name
     * @throws IllegalArgumentException if source or target is blank
     */
    public void addEncodingMapping(final String source, final String target) {
        if (StringUtil.isBlank(source) || StringUtil.isBlank(target)) {
            throw new IllegalArgumentException("Source and target encodings must not be blank.");
        }