private void checkLeadership()

in curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java [539:602]
56 lines of code
11 McCabe index (conditional complexity)

    private void checkLeadership(List<String> children) throws Exception {
        if (debugCheckLeaderShipLatch != null) {
            debugCheckLeaderShipLatch.await();
        }

        final String localOurPath = ourPath.get();
        List<String> sortedChildren = LockInternals.getSortedChildren(LOCK_NAME, sorter, children);
        int ourIndex = (localOurPath != null) ? sortedChildren.indexOf(ZKPaths.getNodeFromPath(localOurPath)) : -1;

        log.debug("[id={}] checkLeadership with ourPath: {}, children: {}", id, localOurPath, sortedChildren);

        if (ourIndex < 0) {
            log.error("[id={}] failed to find our node; resetting (index: {})", id, ourIndex);
            reset();
            return;
        }

        if (ourIndex == 0) {
            client.getData()
                    .inBackground((client, event) -> {
                        final long ephemeralOwner =
                                event.getStat() != null ? event.getStat().getEphemeralOwner() : -1;
                        final long thisSessionId =
                                client.getZookeeperClient().getZooKeeper().getSessionId();
                        if (ephemeralOwner != thisSessionId) {
                            // this node is gone - reset
                            reset();
                        } else {
                            lastPathIsLeader.set(localOurPath);
                            setLeadership(true);
                        }
                    })
                    .forPath(localOurPath);
            return;
        }

        setLeadership(false);
        String watchPath = sortedChildren.get(ourIndex - 1);
        Watcher watcher = new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                if (state.get() == State.STARTED && event.getType() == Event.EventType.NodeDeleted) {
                    try {
                        getChildren();
                    } catch (Exception ex) {
                        ThreadUtils.checkInterrupted(ex);
                        log.error("[id={}] failed to check the leadership.", id, ex);
                    }
                }
            }
        };

        BackgroundCallback callback = new BackgroundCallback() {
            @Override
            public void processResult(CuratorFramework client, CuratorEvent event) throws Exception {
                if (event.getResultCode() == KeeperException.Code.NONODE.intValue()) {
                    log.debug("[id={}] previous node is gone; retry getChildren", id);
                    getChildren();
                }
            }
        };
        // use getData() instead of exists() to avoid leaving unneeded watchers which is a type of resource leak
        client.getData().usingWatcher(watcher).inBackground(callback).forPath(ZKPaths.makePath(latchPath, watchPath));
    }