protected ProgressEvent handleRequest()

in aws-rds-optiongroup/src/main/java/software/amazon/rds/optiongroup/CreateHandler.java [29:75]
47 lines of code
3 McCabe index (conditional complexity)

    protected ProgressEvent<ResourceModel, CallbackContext> handleRequest(
            final AmazonWebServicesClientProxy proxy,
            final ResourceHandlerRequest<ResourceModel> request,
            final CallbackContext callbackContext,
            final ProxyClient<RdsClient> proxyClient,
            final Logger logger
    ) {
        return ProgressEvent.progress(request.getDesiredResourceState(), callbackContext)
                .then(progress -> {
                    final ResourceModel model = request.getDesiredResourceState();
                    if (StringUtils.isNullOrEmpty(model.getOptionGroupName())) {
                        model.setOptionGroupName(IdentifierUtils.generateResourceIdentifier(
                                Optional.ofNullable(request.getStackId()).orElse(STACK_NAME),
                                Optional.ofNullable(request.getLogicalResourceIdentifier()).orElse(RESOURCE_IDENTIFIER),
                                request.getClientRequestToken(),
                                RESOURCE_ID_MAX_LENGTH
                        ).toLowerCase());
                    }
                    return ProgressEvent.progress(model, progress.getCallbackContext());
                })
                .then(progress -> proxy.initiate("rds::create-option-group", proxyClient, progress.getResourceModel(), progress.getCallbackContext())
                        .translateToServiceRequest(model -> Translator.createOptionGroupRequest(
                                model,
                                mergeMaps(
                                        request.getSystemTags(),
                                        request.getDesiredResourceTags()
                                )
                        ))
                        .backoffDelay(config.getBackoff())
                        .makeServiceCall((createRequest, proxyInvocation) -> proxyInvocation.injectCredentialsAndInvokeV2(
                                createRequest,
                                proxyInvocation.client()::createOptionGroup
                        ))
                        .handleError((createRequest, exception, client, resourceModel, ctx) -> Commons.handleException(
                                ProgressEvent.progress(resourceModel, ctx),
                                exception,
                                DEFAULT_OPTION_GROUP_ERROR_RULE_SET
                        ))
                        .progress())
                .then(progress -> {
                    if (CollectionUtils.isNullOrEmpty(progress.getResourceModel().getOptionConfigurations())) {
                        return progress;
                    }
                    return updateOptionGroup(proxy, proxyClient, progress);
                })
                .then(progress -> new ReadHandler().handleRequest(proxy, request, callbackContext, proxyClient, logger));
    }