Method root

impl/src/main/java/io/jsonwebtoken/impl/security/KeysBridge.java:65–68

If the specified key is a KeySupplier, the 'root' (lowest level) key that may exist in a KeySupplier chain is returned, otherwise the key is returned. @param key the key to check if it is a KeySupplier @param the key type @return the lowest-level/root key

(K key)

     * @return the lowest-level/root key available.
     */
    @SuppressWarnings("unchecked")
    public static <K extends Key> K root(K key) {
        return (key instanceof KeySupplier<?>) ? (K) root((KeySupplier<?>) key) : key;
    }

    public static <K extends Key> K root(KeySupplier<K> supplier) {
        Assert.notNull(supplier, "KeySupplier canot be null.");