T doGet()

in evcache-core/src/main/java/com/netflix/evcache/EVCacheImpl.java [433:529]
95 lines of code
42 McCabe index (conditional complexity)

    <T> T doGet(EVCacheKey evcKey , Transcoder<T> tc) throws EVCacheException {
        final boolean throwExc = doThrowException();
        EVCacheClient client = _pool.getEVCacheClientForRead();
        if (client == null) {
            incrementFastFail(EVCacheMetricsFactory.NULL_CLIENT, Call.GET);
            if (throwExc) throw new EVCacheException("Could not find a client to get the data APP " + _appName);
            return null; // Fast failure
        }

        final EVCacheEvent event = createEVCacheEvent(Collections.singletonList(client), Call.GET);
        if (event != null) {
            event.setEVCacheKeys(Arrays.asList(evcKey));
            try {
                if (shouldThrottle(event)) {
                    incrementFastFail(EVCacheMetricsFactory.THROTTLED, Call.GET);
                    if (throwExc) throw new EVCacheException("Request Throttled for app " + _appName + " & key " + evcKey);
                    return null;
                }
            } catch(EVCacheException ex) {
                if(throwExc) throw ex;
                incrementFastFail(EVCacheMetricsFactory.THROTTLED, Call.GET);
                return null;
            }
            startEvent(event);
        }

        final long start = EVCacheMetricsFactory.getInstance().getRegistry().clock().wallTime();
        String status = EVCacheMetricsFactory.SUCCESS;
        String cacheOperation = EVCacheMetricsFactory.YES;
        int tries = 1;
        try {
            final boolean hasZF = hasZoneFallback();
            boolean throwEx = hasZF ? false : throwExc;
            T data = getData(client, evcKey, tc, throwEx, hasZF);
            if (data == null && hasZF) {
                final List<EVCacheClient> fbClients = _pool.getEVCacheClientsForReadExcluding(client.getServerGroup());
                if (fbClients != null && !fbClients.isEmpty()) {
                    for (int i = 0; i < fbClients.size(); i++) {
                        final EVCacheClient fbClient = fbClients.get(i);
                        if(i >= fbClients.size() - 1) throwEx = throwExc;
                        if (event != null) {
                            try {
                                if (shouldThrottle(event)) {
                                    status = EVCacheMetricsFactory.THROTTLED;
                                    if (throwExc) throw new EVCacheException("Request Throttled for app " + _appName + " & key " + evcKey);
                                    return null;
                                }
                            } catch(EVCacheException ex) {
                                if(throwExc) throw ex;
                                status = EVCacheMetricsFactory.THROTTLED;
                                return null;
                            }
                        }
                        tries++;
                        data = getData(fbClient, evcKey, tc, throwEx, (i < fbClients.size() - 1) ? true : false);
                        if (log.isDebugEnabled() && shouldLog()) log.debug("Retry for APP " + _appName + ", key [" + evcKey + (log.isTraceEnabled() ? "], Value [" + data : "") + "], ServerGroup : " + fbClient.getServerGroup());
                        if (data != null) {
                            client = fbClient;
                            break;
                        }
                    }
                }
            }
            if (data != null) {
                if (event != null) event.setAttribute("status", "GHIT");
            } else {
                cacheOperation = EVCacheMetricsFactory.NO;
                if (event != null) event.setAttribute("status", "GMISS");
                if (log.isInfoEnabled() && shouldLog()) log.info("GET : APP " + _appName + " ; cache miss for key : " + evcKey);
            }
            if (log.isDebugEnabled() && shouldLog()) log.debug("GET : APP " + _appName + ", key [" + evcKey + (log.isTraceEnabled() ? "], Value [" + data : "") + "], ServerGroup : " + client.getServerGroup());
            if (event != null) endEvent(event);
            return data;
        } catch (net.spy.memcached.internal.CheckedOperationTimeoutException ex) {
            status = EVCacheMetricsFactory.TIMEOUT;
            if (event != null) {
                event.setStatus(status);
                eventError(event, ex);
            }
            if (!throwExc) return null;
            throw new EVCacheException("CheckedOperationTimeoutException getting data for APP " + _appName + ", key = " + evcKey
                    + ".\nYou can set the following property to increase the timeout " + _appName
                    + ".EVCacheClientPool.readTimeout=<timeout in milli-seconds>", ex);
        } catch (Exception ex) {
            status = EVCacheMetricsFactory.ERROR;
            if (event != null) {
                event.setStatus(status);
                eventError(event, ex);
            }
            if (!throwExc) return null;
            throw new EVCacheException("Exception getting data for APP " + _appName + ", key = " + evcKey, ex);
        } finally {
            final long duration = EVCacheMetricsFactory.getInstance().getRegistry().clock().wallTime()- start;
            getTimer(Call.GET.name(), EVCacheMetricsFactory.READ, cacheOperation, status, tries, maxReadDuration.get().intValue(), client.getServerGroup()).record(duration, TimeUnit.MILLISECONDS);
            if (log.isDebugEnabled() && shouldLog()) log.debug("GET : APP " + _appName + ", Took " + duration + " milliSec.");
        }
    }