@Override
    public TristateResult hasPermission(String permission) {
        PermissionDefault def = PermissionDefault.fromPermission(this.plugin.getPermissionMap().get(permission));
        if (def == null) {
            return TristateResult.UNDEFINED;
        }
        return RESULT_FACTORY.result(Tristate.of(def.getValue(this.isOp)));
    }
Permission Processor for Nukkits "default" permission system.
nukkit/src/main/java/me/lucko/luckperms/nukkit/calculator/PermissionMapProcessor.java