assertEquals(value, documentHelper.encodeSimilarDocHash(hash));
        hash = "$H4sIAAAAAAAAAAMAAAAAAAAAAAA";
        value = "$H4sIAAAAAAAAAAMAAAAAAAAAAAA";
        assertEquals(value, documentHelper.encodeSimilarDocHash(hash));

        assertNull(documentHelper.encodeSimilarDocHash(null));
    }

    public void test_decodeSimilarDocHash() {
        DocumentHelper documentHelper = new DocumentHelper();

        }
    }

    /**
     * Decodes a similar document hash from its compressed and encoded form.
     * Reverses the encoding process applied by encodeSimilarDocHash.
     *
     * @param hash the encoded hash string to decode
     * @return the decoded hash string, or the original hash if decoding fails
     */
    public String decodeSimilarDocHash(final String hash) {

     */
    public static String sdh(final String input) {
        if (StringUtil.isBlank(input)) {
            return input;
        }
        return ComponentUtil.getDocumentHelper().encodeSimilarDocHash(input);
    }

    /**
     * Joins array or list elements into a single space-separated string.
     *
     * @param input the input object (String[], List, or String)