private void makeSequence()

in oap-server/server-library/library-module/src/main/java/org/apache/skywalking/oap/server/library/module/BootstrapFlow.java [56:120]
60 lines of code
14 McCabe index (conditional complexity)

    private void makeSequence() throws CycleDependencyException, ModuleNotFoundException {
        List<ModuleProvider> allProviders = new ArrayList<>();
        for (final ModuleDefine module : loadedModules.values()) {
            String[] requiredModules = module.provider().requiredModules();
            if (requiredModules != null) {
                for (String requiredModule : requiredModules) {
                    if (!loadedModules.containsKey(requiredModule)) {
                        throw new ModuleNotFoundException(
                            requiredModule + " module is required by "
                                + module.provider().getModuleName() + "."
                                + module.provider().name() + ", but not found.");
                    }
                }
            }

            allProviders.add(module.provider());
        }

        do {
            int numOfToBeSequenced = allProviders.size();
            for (int i = 0; i < allProviders.size(); i++) {
                ModuleProvider provider = allProviders.get(i);
                String[] requiredModules = provider.requiredModules();
                if (CollectionUtils.isNotEmpty(requiredModules)) {
                    boolean isAllRequiredModuleStarted = true;
                    for (String module : requiredModules) {
                        // find module in all ready existed startupSequence
                        boolean exist = false;
                        for (ModuleProvider moduleProvider : startupSequence) {
                            if (moduleProvider.getModuleName().equals(module)) {
                                exist = true;
                                break;
                            }
                        }
                        if (!exist) {
                            isAllRequiredModuleStarted = false;
                            break;
                        }
                    }

                    if (isAllRequiredModuleStarted) {
                        startupSequence.add(provider);
                        allProviders.remove(i);
                        i--;
                    }
                } else {
                    startupSequence.add(provider);
                    allProviders.remove(i);
                    i--;
                }
            }

            if (numOfToBeSequenced == allProviders.size()) {
                StringBuilder unSequencedProviders = new StringBuilder();
                allProviders.forEach(provider -> unSequencedProviders.append(provider.getModuleName())
                                                                     .append("[provider=")
                                                                     .append(provider.getClass().getName())
                                                                     .append("]\n"));
                throw new CycleDependencyException(
                    "Exist cycle module dependencies in \n" + unSequencedProviders.substring(0, unSequencedProviders
                        .length() - 1));
            }
        }
        while (allProviders.size() != 0);
    }