private void updateMemcachedReadInstancesByZone()

in evcache-core/src/main/java/com/netflix/evcache/pool/EVCacheClientPool.java [918:976]
54 lines of code
16 McCabe index (conditional complexity)

    private void updateMemcachedReadInstancesByZone() {
        for (ServerGroup serverGroup : memcachedInstancesByServerGroup.keySet()) {
            final Property<Boolean> isZoneInWriteOnlyMode = writeOnlyFastPropertyMap.get(serverGroup);
            if (isZoneInWriteOnlyMode.get().booleanValue()) {
                if (memcachedReadInstancesByServerGroup.containsKey(serverGroup)) {
                    memcachedReadInstancesByServerGroup.remove(serverGroup);
                }
            } else {
                if (!memcachedReadInstancesByServerGroup.containsKey(serverGroup)) {
                    memcachedReadInstancesByServerGroup.put(serverGroup, memcachedInstancesByServerGroup.get(serverGroup));
                }
            }

            // if we lose over 50% of instances put that zone in writeonly mode.
            final List<EVCacheClient> clients = memcachedReadInstancesByServerGroup.get(serverGroup);
            if (clients != null && !clients.isEmpty()) {
                final EVCacheClient client = clients.get(0);
                if (client != null) {
                    final EVCacheConnectionObserver connectionObserver = client.getConnectionObserver();
                    if (connectionObserver != null) {
                        final int activeServerCount = connectionObserver.getActiveServerCount();
                        final int inActiveServerCount = connectionObserver.getInActiveServerCount();
                        if (inActiveServerCount > activeServerCount) {
                            memcachedReadInstancesByServerGroup.remove(serverGroup);
                            getConfigGauge(EVCacheMetricsFactory.POOL_SERVERGROUP_STATUS, serverGroup).set(Long.valueOf(1));
                        } else {
                            getConfigGauge(EVCacheMetricsFactory.POOL_SERVERGROUP_STATUS, serverGroup).set(Long.valueOf(2));
                        }
                    }
                }
            } else {
                final List<EVCacheClient> clientsWrite = memcachedInstancesByServerGroup.get(serverGroup);
                if (clientsWrite != null && !clientsWrite.isEmpty()) {
                    getConfigGauge(EVCacheMetricsFactory.POOL_SERVERGROUP_STATUS, serverGroup).set(Long.valueOf(0));
                }
            }
        }

        if (memcachedReadInstancesByServerGroup.size() != memcachedFallbackReadInstances.getSize()) {
            memcachedFallbackReadInstances = new ServerGroupCircularIterator(memcachedReadInstancesByServerGroup.keySet());

            Map<String, Set<ServerGroup>> readServerGroupByZoneMap = new ConcurrentHashMap<String, Set<ServerGroup>>();
            for (ServerGroup serverGroup : memcachedReadInstancesByServerGroup.keySet()) {
                Set<ServerGroup> serverGroupList = readServerGroupByZoneMap.get(serverGroup.getZone());
                if (serverGroupList == null) {
                    serverGroupList = new HashSet<ServerGroup>();
                    readServerGroupByZoneMap.put(serverGroup.getZone(), serverGroupList);
                }
                serverGroupList.add(serverGroup);
            }

            Map<String, ServerGroupCircularIterator> _readServerGroupByZone = new ConcurrentHashMap<String, ServerGroupCircularIterator>();
            for (Entry<String, Set<ServerGroup>> readServerGroupByZoneEntry : readServerGroupByZoneMap.entrySet()) {
                _readServerGroupByZone.put(readServerGroupByZoneEntry.getKey(), new ServerGroupCircularIterator(readServerGroupByZoneEntry.getValue()));
            }
            this.readServerGroupByZone = _readServerGroupByZone;
            localServerGroupIterator = readServerGroupByZone.get(_zone);
        }
    }