public Map getResourceFromRemote()

in dubbo-xds/src/main/java/org/apache/dubbo/registry/xds/util/protocol/AbstractProtocol.java [126:182]
52 lines of code
4 McCabe index (conditional complexity)

    public Map<String, T> getResourceFromRemote(Set<String> resourceNames) {
        try {
            resourceLock.lock();
            CompletableFuture<Map<String, T>> future = new CompletableFuture<>();
            observeResourcesName = resourceNames;
            Set<String> consumerObserveResourceNames = new HashSet<>();
            if (resourceNames.isEmpty()) {
                consumerObserveResourceNames.add(emptyResourceName);
            } else {
                consumerObserveResourceNames = resourceNames;
            }

            Consumer<Map<String, T>> futureConsumer = future::complete;
            try {
                writeLock.lock();
                ConcurrentHashMapUtils.computeIfAbsent(
                                (ConcurrentHashMap<Set<String>, List<Consumer<Map<String, T>>>>) consumerObserveMap,
                                consumerObserveResourceNames,
                                key -> new ArrayList<>())
                        .add(futureConsumer);
            } finally {
                writeLock.unlock();
            }

            Set<String> resourceNamesToObserve = new HashSet<>(resourceNames);
            resourceNamesToObserve.addAll(resourcesMap.keySet());
            adsObserver.request(buildDiscoveryRequest(resourceNamesToObserve));
            logger.info("Send xDS Observe request to remote. Resource count: " + resourceNamesToObserve.size()
                    + ". Resource Type: " + getTypeUrl());

            try {
                Map<String, T> result = future.get();

                try {
                    writeLock.lock();
                    consumerObserveMap.get(consumerObserveResourceNames).removeIf(o -> o.equals(futureConsumer));
                } finally {
                    writeLock.unlock();
                }

                return result;
            } catch (InterruptedException e) {
                logger.error(
                        INTERNAL_INTERRUPTED,
                        "",
                        "",
                        "InterruptedException occur when request control panel. error=",
                        e);
                Thread.currentThread().interrupt();
            } catch (Exception e) {
                logger.error(PROTOCOL_FAILED_REQUEST, "", "", "Error occur when request control panel. error=", e);
            }
        } finally {
            resourceLock.unlock();
        }
        return Collections.emptyMap();
    }