/**
* description of authorizer implementation, like, valid principal types.
* @return description of authorizer implementation.
*/
public String description()

public interface Authorizer extends Configurable {

    /**
     * @param session   The session being authenticated.
     * @param operation Type of operation client is trying to perform on resource.
     * @param resource  Resource the client is trying to access.
     * @return
     */
    public boolean authorize(Session session, Operation operation, Resource resource);

    /**
     * implementation specific description, like, supported principal types.
     *
     * @return implementation specific description.
     */
    public String description();

    /**
     * add the acls to resource, this is an additive operation so existing acls will not be overwritten, instead these new
     * acls will be added to existing acls.
     *
     * @param acls     set of acls to add to existing acls
     * @param resource the resource to which these acls should be attached.
     */
    public void addAcls(Set<Acl> acls, Resource resource);

    /**
     * remove these acls from the resource.
     *
     * @param acls     set of acls to be removed.
     * @param resource resource from which the acls should be removed.
     * @return true if some acl got removed, false if no acl was removed.
     */
    public boolean removeAcls(Set<Acl> acls, Resource resource);

    /**
     * remove a resource along with all of its acls from acl store.
     *
     * @param resource
     * @return
     */
    public boolean removeAcls(Resource resource);

    /**
     * get set of acls for this resource
     *
     * @param resource
     * @return empty set if no acls are found, otherwise the acls for the resource.
     */
    public Set<Acl> acls(Resource resource);

    /**
     * get the acls for this principal.
     *
     * @param principal
     * @return empty Map if no acls exist for this principal, otherwise a map of resource -> acls for the principal.
     */
    public Map<Resource, Set<Acl>> acls(KafkaPrincipal principal);

    /**
     * gets the map of resource to acls for all resources.
     */
    public Map<Resource, Set<Acl>> acls();

    /**
     * Closes this instance.
     */
    public void close();

}