聊聊rocketmq的registerConsumer与unregisterConsumer

public class MQClientInstance {
    private final static long LOCK_TIMEOUT_MILLIS = 3000;
    private final InternalLogger log = ClientLogger.getLog();
    private final ClientConfig clientConfig;
    private final int instanceIndex;
    private final String clientId;
    private final long bootTimestamp = System.currentTimeMillis();
    private final ConcurrentMap<String/* group */, MQProducerInner> producerTable = new ConcurrentHashMap<String, MQProducerInner>();
    private final ConcurrentMap<String/* group */, MQConsumerInner> consumerTable = new ConcurrentHashMap<String, MQConsumerInner>();
​
    //......
​
    public boolean registerConsumer(final String group, final MQConsumerInner consumer) {
        if (null == group || null == consumer) {
            return false;
        }
​
        MQConsumerInner prev = this.consumerTable.putIfAbsent(group, consumer);
        if (prev != null) {
            log.warn("the consumer group[" + group + "] exist already.");
            return false;
        }
​
        return true;
    }
​
    public void unregisterConsumer(final String group) {
        this.consumerTable.remove(group);
        this.unregisterClientWithLock(null, group);
    }
​
    private void unregisterClientWithLock(final String producerGroup, final String consumerGroup) {
        try {
            if (this.lockHeartbeat.tryLock(LOCK_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)) {
                try {
                    this.unregisterClient(producerGroup, consumerGroup);
                } catch (Exception e) {
                    log.error("unregisterClient exception", e);
                } finally {
                    this.lockHeartbeat.unlock();
                }
            } else {
                log.warn("lock heartBeat, but failed.");
            }
        } catch (InterruptedException e) {
            log.warn("unregisterClientWithLock exception", e);
        }
    }
​
    private void unregisterClient(final String producerGroup, final String consumerGroup) {
        Iterator<Entry<String, HashMap<Long, String>>> it = this.brokerAddrTable.entrySet().iterator();
        while (it.hasNext()) {
            Entry<String, HashMap<Long, String>> entry = it.next();
            String brokerName = entry.getKey();
            HashMap<Long, String> oneTable = entry.getValue();
​
            if (oneTable != null) {
                for (Map.Entry<Long, String> entry1 : oneTable.entrySet()) {
                    String addr = entry1.getValue();
                    if (addr != null) {
                        try {
                            this.mQClientAPIImpl.unregisterClient(addr, this.clientId, producerGroup, consumerGroup, 3000);
                            log.info("unregister client[Producer: {} Consumer: {}] from broker[{} {} {}] success", producerGroup, consumerGroup, brokerName, entry1.getKey(), addr);
                        } catch (RemotingException e) {
                            log.error("unregister client exception from broker: " + addr, e);
                        } catch (InterruptedException e) {
                            log.error("unregister client exception from broker: " + addr, e);
                        } catch (MQBrokerException e) {
                            log.error("unregister client exception from broker: " + addr, e);
                        }
                    }
                }
            }
        }
    }
​
    //......
}

public class MQClientAPIImpl {
​
    //......
​
    public void unregisterClient(
        final String addr,
        final String clientID,
        final String producerGroup,
        final String consumerGroup,
        final long timeoutMillis
    ) throws RemotingException, MQBrokerException, InterruptedException {
        final UnregisterClientRequestHeader requestHeader = new UnregisterClientRequestHeader();
        requestHeader.setClientID(clientID);
        requestHeader.setProducerGroup(producerGroup);
        requestHeader.setConsumerGroup(consumerGroup);
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.UNREGISTER_CLIENT, requestHeader);
​
        RemotingCommand response = this.remotingClient.invokeSync(addr, request, timeoutMillis);
        assert response != null;
        switch (response.getCode()) {
            case ResponseCode.SUCCESS: {
                return;
            }
            default:
                break;
        }
​
        throw new MQBrokerException(response.getCode(), response.getRemark());
    }
​
    //......
}

public class DefaultMQPushConsumerImpl implements MQConsumerInner {
​
    //......
​
    public synchronized void start() throws MQClientException {
        switch (this.serviceState) {
            case CREATE_JUST:
                log.info("the consumer [{}] start beginning. messageModel={}, isUnitMode={}", this.defaultMQPushConsumer.getConsumerGroup(),
                    this.defaultMQPushConsumer.getMessageModel(), this.defaultMQPushConsumer.isUnitMode());
                this.serviceState = ServiceState.START_FAILED;
​
                this.checkConfig();
​
                this.copySubscription();
​
                if (this.defaultMQPushConsumer.getMessageModel() == MessageModel.CLUSTERING) {
                    this.defaultMQPushConsumer.changeInstanceNameToPID();
                }
​
                this.mQClientFactory = MQClientManager.getInstance().getAndCreateMQClientInstance(this.defaultMQPushConsumer, this.rpcHook);
​
                this.rebalanceImpl.setConsumerGroup(this.defaultMQPushConsumer.getConsumerGroup());
                this.rebalanceImpl.setMessageModel(this.defaultMQPushConsumer.getMessageModel());
                this.rebalanceImpl.setAllocateMessageQueueStrategy(this.defaultMQPushConsumer.getAllocateMessageQueueStrategy());
                this.rebalanceImpl.setmQClientFactory(this.mQClientFactory);
​
                this.pullAPIWrapper = new PullAPIWrapper(
                    mQClientFactory,
                    this.defaultMQPushConsumer.getConsumerGroup(), isUnitMode());
                this.pullAPIWrapper.registerFilterMessageHook(filterMessageHookList);
​
                if (this.defaultMQPushConsumer.getOffsetStore() != null) {
                    this.offsetStore = this.defaultMQPushConsumer.getOffsetStore();
                } else {
                    switch (this.defaultMQPushConsumer.getMessageModel()) {
                        case BROADCASTING:
                            this.offsetStore = new LocalFileOffsetStore(this.mQClientFactory, this.defaultMQPushConsumer.getConsumerGroup());
                            break;
                        case CLUSTERING:
                            this.offsetStore = new RemoteBrokerOffsetStore(this.mQClientFactory, this.defaultMQPushConsumer.getConsumerGroup());
                            break;
                        default:
                            break;
                    }
                    this.defaultMQPushConsumer.setOffsetStore(this.offsetStore);
                }
                this.offsetStore.load();
​
                if (this.getMessageListenerInner() instanceof MessageListenerOrderly) {
                    this.consumeOrderly = true;
                    this.consumeMessageService =
                        new ConsumeMessageOrderlyService(this, (MessageListenerOrderly) this.getMessageListenerInner());
                } else if (this.getMessageListenerInner() instanceof MessageListenerConcurrently) {
                    this.consumeOrderly = false;
                    this.consumeMessageService =
                        new ConsumeMessageConcurrentlyService(this, (MessageListenerConcurrently) this.getMessageListenerInner());
                }
​
                this.consumeMessageService.start();
​
                boolean registerOK = mQClientFactory.registerConsumer(this.defaultMQPushConsumer.getConsumerGroup(), this);
                if (!registerOK) {
                    this.serviceState = ServiceState.CREATE_JUST;
                    this.consumeMessageService.shutdown();
                    throw new MQClientException("The consumer group[" + this.defaultMQPushConsumer.getConsumerGroup()
                        + "] has been created before, specify another name please." + FAQUrl.suggestTodo(FAQUrl.GROUP_NAME_DUPLICATE_URL),
                        null);
                }
​
                mQClientFactory.start();
                log.info("the consumer [{}] start OK.", this.defaultMQPushConsumer.getConsumerGroup());
                this.serviceState = ServiceState.RUNNING;
                break;
            case RUNNING:
            case START_FAILED:
            case SHUTDOWN_ALREADY:
                throw new MQClientException("The PushConsumer service state not OK, maybe started once, "
                    + this.serviceState
                    + FAQUrl.suggestTodo(FAQUrl.CLIENT_SERVICE_NOT_OK),
                    null);
            default:
                break;
        }
​
        this.updateTopicSubscribeInfoWhenSubscriptionChanged();
        this.mQClientFactory.checkClientInBroker();
        this.mQClientFactory.sendHeartbeatToAllBrokerWithLock();
        this.mQClientFactory.rebalanceImmediately();
    }
​
    //......
}