protected List<Authorizer> computeAuthorizersFromNames(final String authorizerNames, final Map<String, Authorizer> authorizersMap) {
        assertNotNull("authorizersMap", authorizersMap);
        List<Authorizer> authorizers = new ArrayList<>();
        val names = authorizerNames.split(Pac4jConstants.ELEMENT_SEPARATOR);
        val nb = names.length;
        for (var i = 0; i < nb; i++) {
            val name = names[i].trim();
            if (!DefaultAuthorizers.NONE.equalsIgnoreCase(name)){
                val result = retrieveAuthorizer(name, authorizersMap);
                // we must have an authorizer defined for this name
                assertTrue(result != null, "The authorizer '" + name + "' must be defined in the security configuration");
                authorizers.add(result);
            }
        }
        return authorizers;
    }
<p>computeAuthorizersFromNames.</p>

@param authorizerNames a {@link String} object
@param authorizersMap a {@link Map} object
@return a {@link List} object
pac4j-core/src/main/java/org/pac4j/core/authorization/checker/DefaultAuthorizationChecker.java