public CompletableFuture send()

in dubbo-remoting-extensions/dubbo-remoting-http/src/main/java/org/apache/dubbo/remoting/http/restclient/HttpClientRestClient.java [62:132]
57 lines of code
7 McCabe index (conditional complexity)

    public CompletableFuture<RestResult> send(RequestTemplate requestTemplate) {

        HttpRequestBase httpRequest = null;
        String httpMethod = requestTemplate.getHttpMethod();

        httpRequest = createHttpUriRequest(httpMethod, requestTemplate);

        if (httpRequest instanceof HttpEntityEnclosingRequest) {
            ((HttpEntityEnclosingRequestBase) httpRequest)
                    .setEntity(new ByteArrayEntity(requestTemplate.getSerializedBody()));
        }

        Map<String, Collection<String>> allHeaders = requestTemplate.getAllHeaders();

        allHeaders.remove("Content-Length");
        // header
        for (String headerName : allHeaders.keySet()) {
            Collection<String> headerValues = allHeaders.get(headerName);

            for (String headerValue : headerValues) {
                httpRequest.addHeader(headerName, headerValue);
            }
        }

        httpRequest.setConfig(getRequestConfig(httpClientConfig));

        CompletableFuture<RestResult> future = new CompletableFuture<>();
        try {
            CloseableHttpResponse response = closeableHttpClient.execute(httpRequest);
            future.complete(new RestResult() {
                @Override
                public String getContentType() {
                    Header header = response.getFirstHeader("Content-Type");
                    return header == null ? null : header.getValue();
                }

                @Override
                public byte[] getBody() throws IOException {
                    if (response.getEntity() == null) {
                        return new byte[0];
                    }
                    return IOUtils.toByteArray(response.getEntity().getContent());
                }

                @Override
                public Map<String, List<String>> headers() {
                    return Arrays.stream(response.getAllHeaders())
                            .collect(Collectors.toMap(Header::getName, h -> Collections.singletonList(h.getValue())));
                }

                @Override
                public byte[] getErrorResponse() throws IOException {
                    return getBody();
                }

                @Override
                public int getResponseCode() {
                    return response.getStatusLine().getStatusCode();
                }

                @Override
                public String getMessage() throws IOException {
                    return appendErrorMessage(
                            response.getStatusLine().getReasonPhrase(), new String(getErrorResponse()));
                }
            });
        } catch (IOException e) {
            future.completeExceptionally(e);
        }
        return future;
    }