cannal源码赏析- common模块

public class MigrateMap {

    public static <K, V> ConcurrentMap<K, V> makeComputingMap(CacheBuilder<Object, Object> builder,
                                                              Function<? super K, ? extends V> computingFunction) {
        final Function<? super K, ? extends V> function = computingFunction;
        LoadingCache<K, V> computingCache = builder.build(new CacheLoader<K, V>() {

            @Override
            public V load(K key) throws Exception {
                return function.apply(key);
            }
        });

        return new MigrateConcurrentMap<>(computingCache);
    }

    public static <K, V> ConcurrentMap<K, V> makeComputingMap(Function<? super K, ? extends V> computingFunction) {
        return makeComputingMap(CacheBuilder.newBuilder(), computingFunction);
    }

    final static class MigrateConcurrentMap<K, V> implements ConcurrentMap<K, V> {

        private final LoadingCache<K, V>  computingCache;

        private final ConcurrentMap<K, V> cacheView;

        MigrateConcurrentMap(LoadingCache<K, V> computingCache){
            this.computingCache = computingCache;
            this.cacheView = computingCache.asMap();
        }

        @Override
        public int size() {
            return cacheView.size();
        }

        @Override
        public boolean isEmpty() {
            return cacheView.isEmpty();
        }

        @Override
        public boolean containsKey(Object key) {
            return cacheView.containsKey(key);
        }

        @Override
        public boolean containsValue(Object value) {
            return cacheView.containsValue(value);
        }

        @Override
        public V get(Object key) {
            try {
                return computingCache.get((K) key);
            } catch (ExecutionException e) {
                throw new RuntimeException(e);
            }
        }

        @Override
        public V put(K key, V value) {
            return cacheView.put(key, value);
        }

        @Override
        public V remove(Object key) {
            return cacheView.remove(key);
        }

        @Override
        public void putAll(Map<? extends K, ? extends V> m) {
            cacheView.putAll(m);
        }

        @Override
        public void clear() {
            cacheView.clear();
        }

        @Override
        public Set<K> keySet() {
            return cacheView.keySet();
        }

        @Override
        public Collection<V> values() {
            return cacheView.values();
        }

        @Override
        public Set<Entry<K, V>> entrySet() {
            return cacheView.entrySet();
        }

        @Override
        public V putIfAbsent(K key, V value) {
            return cacheView.putIfAbsent(key, value);
        }

        @Override
        public boolean remove(Object key, Object value) {
            return cacheView.remove(key, value);
        }

        @Override
        public boolean replace(K key, V oldValue, V newValue) {
            return cacheView.replace(key, oldValue, newValue);
        }

        @Override
        public V replace(K key, V value) {
            return cacheView.replace(key, value);
        }

        @Override
        public String toString() {
            return cacheView.toString();
        }
    }
}

ServerRunningMonitors.setRunningMonitors(MigrateMap.makeComputingMap((Function<String, ServerRunningMonitor>) destination -> {
    ServerRunningMonitor runningMonitor = new ServerRunningMonitor(serverData);
    runningMonitor.setDestination(destination);
    runningMonitor.setListener(new ServerRunningListener() {

        public void processActiveEnter() {
            try {
                MDC.put(CanalConstants.MDC_DESTINATION, String.valueOf(destination));
                embeddedCanalServer.start(destination);
                if (canalMQStarter != null) {
                    canalMQStarter.startDestination(destination);
                }
            } finally {
                MDC.remove(CanalConstants.MDC_DESTINATION);
            }
        }

        public void processActiveExit() {
            try {
                MDC.put(CanalConstants.MDC_DESTINATION, String.valueOf(destination));
                if (canalMQStarter != null) {
                    canalMQStarter.stopDestination(destination);
                }
                embeddedCanalServer.stop(destination);
            } finally {
                MDC.remove(CanalConstants.MDC_DESTINATION);
            }
        }

        public void processStart() {
            try {
                if (zkclientx != null) {
                    final String path = ZookeeperPathUtils.getDestinationClusterNode(destination,
                        registerIp + ":" + port);
                    initCid(path);
                    zkclientx.subscribeStateChanges(new IZkStateListener() {

                        public void handleStateChanged(KeeperState state) throws Exception {

                        }

                        public void handleNewSession() throws Exception {
                            initCid(path);
                        }

                        @Override
                        public void handleSessionEstablishmentError(Throwable error) throws Exception {
                            logger.error("failed to connect to zookeeper", error);
                        }
                    });
                }
            } finally {
                MDC.remove(CanalConstants.MDC_DESTINATION);
            }
        }

        public void processStop() {
            try {
                MDC.put(CanalConstants.MDC_DESTINATION, String.valueOf(destination));
                if (zkclientx != null) {
                    final String path = ZookeeperPathUtils.getDestinationClusterNode(destination,
                        registerIp + ":" + port);
                    releaseCid(path);
                }
            } finally {
                MDC.remove(CanalConstants.MDC_DESTINATION);
            }
        }

    });
    if (zkclientx != null) {
        runningMonitor.setZkClient(zkclientx);
    }
    // 触发创建一下cid节点
    runningMonitor.init();
    return runningMonitor;
}));

public class BooleanMutex {

    private final Sync sync;

    public BooleanMutex(){
        sync = new Sync();
        set(false);
    }

    public BooleanMutex(Boolean mutex){
        sync = new Sync();
        set(mutex);
    }

    /**
     * 阻塞等待Boolean为true
     * 
     * @throws InterruptedException if the current thread is interrupted
     */
    public void get() throws InterruptedException {
        sync.innerGet();
    }

    /**
     * 阻塞等待Boolean为true,允许设置超时时间
     * 
     * @param timeout
     * @param unit
     * @throws InterruptedException
     * @throws TimeoutException
     */
    public void get(long timeout, TimeUnit unit) throws InterruptedException, TimeoutException {
        sync.innerGet(unit.toNanos(timeout));
    }

    /**
     * 重新设置对应的Boolean mutex
     * 
     * @param mutex
     */
    public void set(Boolean mutex) {
        if (mutex) {
            sync.innerSetTrue();
        } else {
            sync.innerSetFalse();
        }
    }

    public boolean state() {
        return sync.innerState();
    }

    /**
     * Synchronization control for BooleanMutex. Uses AQS sync state to
     * represent run status
     */
    private static final class Sync extends AbstractQueuedSynchronizer {

        private static final long serialVersionUID = 2559471934544126329L;
        /** State value representing that TRUE */
        private static final int  TRUE             = 1;
        /** State value representing that FALSE */
        private static final int  FALSE            = 2;

        private boolean isTrue(int state) {
            return (state & TRUE) != 0;
        }

        /**
         * 实现AQS的接口，获取共享锁的判断
         */
        protected int tryAcquireShared(int state) {
            // 如果为true，直接允许获取锁对象
            // 如果为false，进入阻塞队列，等待被唤醒
            return isTrue(getState()) ? 1 : -1;
        }

        /**
         * 实现AQS的接口，释放共享锁的判断
         */
        protected boolean tryReleaseShared(int ignore) {
            // 始终返回true，代表可以release
            return true;
        }

        boolean innerState() {
            return isTrue(getState());
        }

        void innerGet() throws InterruptedException {
            acquireSharedInterruptibly(0);
        }

        void innerGet(long nanosTimeout) throws InterruptedException, TimeoutException {
            if (!tryAcquireSharedNanos(0, nanosTimeout)) throw new TimeoutException();
        }

        void innerSetTrue() {
            for (;;) {
                int s = getState();
                if (s == TRUE) {
                    return; // 直接退出
                }
                if (compareAndSetState(s, TRUE)) {// cas更新状态，避免并发更新true操作
                    releaseShared(0);// 释放一下锁对象，唤醒一下阻塞的Thread
                    return;
                }
            }
        }

        void innerSetFalse() {
            for (;;) {
                int s = getState();
                if (s == FALSE) {
                    return; // 直接退出
                }
                if (compareAndSetState(s, FALSE)) {// cas更新状态，避免并发更新false操作
                    return;
                }
            }
        }

    }

}

// 1. 
private BooleanMutex               mutex        = new BooleanMutex(false);

// 2. 初始化
if (!isMine(runningData.getAddress())) {
    mutex.set(false);
}

// 3. 启动
private void initRunning() {
    if (!isStart()) {
        return;
    }

    String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
    // 序列化
    byte[] bytes = JsonUtils.marshalToByte(serverData);
    try {
        mutex.set(false);
        zkClient.create(path, bytes, CreateMode.EPHEMERAL);
        activeData = serverData;
        processActiveEnter();// 触发一下事件
        mutex.set(true);
        release = false;
    } catch (ZkNodeExistsException e) {
        bytes = zkClient.readData(path, true);
        if (bytes == null) {// 如果不存在节点，立即尝试一次
            initRunning();
        } else {
            activeData = JsonUtils.unmarshalFromByte(bytes, ServerRunningData.class);
        }
    } catch (ZkNoNodeException e) {
        zkClient.createPersistent(ZookeeperPathUtils.getDestinationPath(destination), true); // 尝试创建父节点
        initRunning();
    }
}

// 4. 真正启动

/**
 * 阻塞等待自己成为active，如果自己成为active，立马返回
 * 
 * @throws InterruptedException
 */
public void waitForActive() throws InterruptedException {
    initRunning();
    mutex.get();
}

/**
 * 封装了ZooKeeper，使其支持节点的优先顺序，比如美国机房的节点会优先加载美国对应的zk集群列表，都失败后才会选择加载杭州的zk集群列表 *
 * 
 * @author jianghang 2012-7-10 下午02:31:42
 * @version 1.0.0
 */
public class ZooKeeperx extends ZkConnection {

    private static final String SERVER_COMMA            = ";";
    private static final Logger logger                  = LoggerFactory.getLogger(ZooKeeperx.class);
    private static final Field  clientCnxnField         = ReflectionUtils.findField(ZooKeeper.class, "cnxn");
    private static final Field  hostProviderField       = ReflectionUtils.findField(ClientCnxn.class, "hostProvider");
    private static final Field  serverAddressesField    = ReflectionUtils.findField(StaticHostProvider.class,
                                                            "serverAddresses");
    private static final Field  zookeeperLockField      = ReflectionUtils.findField(ZkConnection.class,
                                                            "_zookeeperLock");
    private static final Field  zookeeperFiled          = ReflectionUtils.findField(ZkConnection.class, "_zk");
    private static final int    DEFAULT_SESSION_TIMEOUT = 90000;

    private final List<String>  _serversList;
    private final int           _sessionTimeOut;

    public ZooKeeperx(String zkServers){
        this(zkServers, DEFAULT_SESSION_TIMEOUT);
    }

    public ZooKeeperx(String zkServers, int sessionTimeOut){
        super(zkServers, sessionTimeOut);
        _serversList = Arrays.asList(StringUtils.split(this.getServers(), SERVER_COMMA));
        _sessionTimeOut = sessionTimeOut;
    }

    @Override
    public void connect(Watcher watcher) {
        ReflectionUtils.makeAccessible(zookeeperLockField);
        ReflectionUtils.makeAccessible(zookeeperFiled);
        Lock _zookeeperLock = (ReentrantLock) ReflectionUtils.getField(zookeeperLockField, this);
        ZooKeeper _zk = (ZooKeeper) ReflectionUtils.getField(zookeeperFiled, this);

        _zookeeperLock.lock();
        try {
            if (_zk != null) {
                throw new IllegalStateException("zk client has already been started");
            }
            String zkServers = _serversList.get(0);

            try {
                logger.debug("Creating new ZookKeeper instance to connect to " + zkServers + ".");
                _zk = new ZooKeeper(zkServers, _sessionTimeOut, watcher);
                configMutliCluster(_zk);
                ReflectionUtils.setField(zookeeperFiled, this, _zk);
            } catch (IOException e) {
                throw new ZkException("Unable to connect to " + zkServers, e);
            }
        } finally {
            _zookeeperLock.unlock();
        }
    }

    // ===============================

    public void configMutliCluster(ZooKeeper zk) {
        if (_serversList.size() == 1) {
            return;
        }
        String cluster1 = _serversList.get(0);
        try {
            if (_serversList.size() > 1) {
                // 强制的声明accessible
                ReflectionUtils.makeAccessible(clientCnxnField);
                ReflectionUtils.makeAccessible(hostProviderField);
                ReflectionUtils.makeAccessible(serverAddressesField);

                // 添加第二组集群列表
                for (int i = 1; i < _serversList.size(); i++) {
                    String cluster = _serversList.get(i);
                    // 强制获取zk中的地址信息
                    ClientCnxn cnxn = (ClientCnxn) ReflectionUtils.getField(clientCnxnField, zk);
                    HostProvider hostProvider = (HostProvider) ReflectionUtils.getField(hostProviderField, cnxn);
                    List<InetSocketAddress> serverAddrs = (List<InetSocketAddress>) ReflectionUtils.getField(serverAddressesField,
                        hostProvider);
                    // 添加第二组集群列表
                    serverAddrs.addAll(new ConnectStringParser(cluster).getServerAddresses());
                }
            }
        } catch (Exception e) {
            try {
                if (zk != null) {
                    zk.close();
                }
            } catch (InterruptedException ie) {
                // ignore interrupt
            }
            throw new ZkException("zookeeper_create_error, serveraddrs=" + cluster1, e);
        }

    }
}

public class ZkClientx extends ZkClient {

    // 对于zkclient进行一次缓存，避免一个jvm内部使用多个zk connection
    private static Map<String, ZkClientx> clients = MigrateMap.makeComputingMap(ZkClientx::new);

    public static ZkClientx getZkClient(String servers) {
        return clients.get(servers);
    }

    public static void clearClients() {
        clients.clear();
    }

    public ZkClientx(String serverstring){
        this(serverstring, Integer.MAX_VALUE);
    }

    public ZkClientx(String zkServers, int connectionTimeout){
        this(new ZooKeeperx(zkServers), connectionTimeout);
    }

    public ZkClientx(String zkServers, int sessionTimeout, int connectionTimeout){
        this(new ZooKeeperx(zkServers, sessionTimeout), connectionTimeout);
    }

    public ZkClientx(String zkServers, int sessionTimeout, int connectionTimeout, ZkSerializer zkSerializer){
        this(new ZooKeeperx(zkServers, sessionTimeout), connectionTimeout, zkSerializer);
    }

    private ZkClientx(IZkConnection connection, int connectionTimeout){
        this(connection, connectionTimeout, new ByteSerializer());
    }

    private ZkClientx(IZkConnection zkConnection, int connectionTimeout, ZkSerializer zkSerializer){
        super(zkConnection, connectionTimeout, zkSerializer);
    }

    /**
     * Create a persistent Sequential node.
     *
     * @param path
     * @param createParents if true all parent dirs are created as well and no
     * {@link ZkNodeExistsException} is thrown in case the path already exists
     * @throws ZkInterruptedException if operation was interrupted, or a
     * required reconnection got interrupted
     * @throws IllegalArgumentException if called from anything except the
     * ZooKeeper event thread
     * @throws ZkException if any ZooKeeper exception occurred
     * @throws RuntimeException if any other exception occurs
     */
    public String createPersistentSequential(String path, boolean createParents) throws ZkInterruptedException,
                                                                                IllegalArgumentException, ZkException,
                                                                                RuntimeException {
        try {
            return create(path, null, CreateMode.PERSISTENT_SEQUENTIAL);
        } catch (ZkNoNodeException e) {
            if (!createParents) {
                throw e;
            }
            String parentDir = path.substring(0, path.lastIndexOf('/'));
            createPersistent(parentDir, createParents);
            return createPersistentSequential(path, createParents);
        }
    }

    /**
     * Create a persistent Sequential node.
     *
     * @param path
     * @param data
     * @param createParents if true all parent dirs are created as well and no
     * {@link ZkNodeExistsException} is thrown in case the path already exists
     * @throws ZkInterruptedException if operation was interrupted, or a
     * required reconnection got interrupted
     * @throws IllegalArgumentException if called from anything except the
     * ZooKeeper event thread
     * @throws ZkException if any ZooKeeper exception occurred
     * @throws RuntimeException if any other exception occurs
     */
    public String createPersistentSequential(String path, Object data, boolean createParents)
                                                                                             throws ZkInterruptedException,
                                                                                             IllegalArgumentException,
                                                                                             ZkException,
                                                                                             RuntimeException {
        try {
            return create(path, data, CreateMode.PERSISTENT_SEQUENTIAL);
        } catch (ZkNoNodeException e) {
            if (!createParents) {
                throw e;
            }
            String parentDir = path.substring(0, path.lastIndexOf('/'));
            createPersistent(parentDir, createParents);
            return createPersistentSequential(path, data, createParents);
        }
    }

    /**
     * Create a persistent Sequential node.
     *
     * @param path
     * @param data
     * @param createParents if true all parent dirs are created as well and no
     * {@link ZkNodeExistsException} is thrown in case the path already exists
     * @throws ZkInterruptedException if operation was interrupted, or a
     * required reconnection got interrupted
     * @throws IllegalArgumentException if called from anything except the
     * ZooKeeper event thread
     * @throws ZkException if any ZooKeeper exception occurred
     * @throws RuntimeException if any other exception occurs
     */
    public void createPersistent(String path, Object data, boolean createParents) throws ZkInterruptedException,
                                                                                 IllegalArgumentException, ZkException,
                                                                                 RuntimeException {
        try {
            create(path, data, CreateMode.PERSISTENT);
        } catch (ZkNodeExistsException e) {
            if (!createParents) {
                throw e;
            }
        } catch (ZkNoNodeException e) {
            if (!createParents) {
                throw e;
            }
            String parentDir = path.substring(0, path.lastIndexOf('/'));
            createPersistent(parentDir, createParents);
            createPersistent(path, data, createParents);
        }
    }
}

/**
 * Otter项目内部使用的ToStringStyle
 * 
 * <pre>
 * 默认Style输出格式：
 * Person[name=John Doe,age=33,smoker=false ,time=2010-04-01 00:00:00]
 * </pre>
 * 
 * @author jianghang 2010-6-18 上午11:35:27
 */
public class CanalToStringStyle extends ToStringStyle {

    private static final long         serialVersionUID = -6568177374288222145L;

    private static final String       DEFAULT_TIME     = "yyyy-MM-dd HH:mm:ss";
    private static final String       DEFAULT_DAY      = "yyyy-MM-dd";

    /**
     * <pre>
     * 输出格式：
     * Person[name=John Doe,age=33,smoker=false ,time=2010-04-01 00:00:00]
     * </pre>
     */
    public static final ToStringStyle TIME_STYLE       = new OtterDateStyle(DEFAULT_TIME);

    /**
     * <pre>
     * 输出格式：
     * Person[name=John Doe,age=33,smoker=false ,day=2010-04-01]
     * </pre>
     */
    public static final ToStringStyle DAY_STYLE        = new OtterDateStyle(DEFAULT_DAY);

    /**
     * <pre>
     * 输出格式：
     * Person[name=John Doe,age=33,smoker=false ,time=2010-04-01 00:00:00]
     * </pre>
     */
    public static final ToStringStyle DEFAULT_STYLE    = CanalToStringStyle.TIME_STYLE;

    // =========================== 自定义style =============================

    /**
     * 支持日期格式化的ToStringStyle
     * 
     * @author li.jinl
     */
    private static class OtterDateStyle extends ToStringStyle {

        private static final long serialVersionUID = 5208917932254652886L;

        // 日期format格式
        private String            pattern;

        public OtterDateStyle(String pattern){
            super();
            this.setUseShortClassName(true);
            this.setUseIdentityHashCode(false);
            // 设置日期format格式
            this.pattern = pattern;
        }

        protected void appendDetail(StringBuffer buffer, String fieldName, Object value) {
            // 增加自定义的date对象处理
            if (value instanceof Date) {
                value = new SimpleDateFormat(pattern).format(value);
            }
            // 后续可以增加其他自定义对象处理
            buffer.append(value);
        }
    }
}

public class Message implements Serializable {

    private static final long      serialVersionUID = 1234034768477580009L;
    private long                   id;
    private List<CanalEntry.Entry> entries          = new ArrayList<>();
    // row data for performance, see:
    // https://github.com/alibaba/canal/issues/726
    private boolean                raw              = true;
    private List<ByteString>       rawEntries       = new ArrayList<>();

    public Message(long id, List<Entry> entries){
        this.id = id;
        this.entries = entries == null ? new ArrayList<>() : entries;
        this.raw = false;
    }

    public Message(long id, boolean raw, List entries){
        this.id = id;
        if (raw) {
            this.rawEntries = entries == null ? new ArrayList<>() : entries;
        } else {
            this.entries = entries == null ? new ArrayList<>() : entries;
        }
        this.raw = raw;
    }

    public Message(long id){
        this.id = id;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public List<Entry> getEntries() {
        return entries;
    }

    public void setEntries(List<CanalEntry.Entry> entries) {
        this.entries = entries;
    }

    public void addEntry(CanalEntry.Entry entry) {
        this.entries.add(entry);
    }

    public void setRawEntries(List<ByteString> rawEntries) {
        this.rawEntries = rawEntries;
    }

    public void addRawEntry(ByteString rawEntry) {
        this.rawEntries.add(rawEntry);
    }

    public List<ByteString> getRawEntries() {
        return rawEntries;
    }

    public boolean isRaw() {
        return raw;
    }

    public void setRaw(boolean raw) {
        this.raw = raw;
    }

    public String toString() {
        return ToStringBuilder.reflectionToString(this, CanalToStringStyle.DEFAULT_STYLE);
    }

}

/**
 * 多线程执行器模板代码，otter中好多地方都写多线程，比较多的都是重复的逻辑代码，抽象一下做个模板把
 *
 * <pre>
 * 示例代码：
 * ExecutorTemplate template = new ExecutorTemplate(executor);
 * ...
 * try {
 *    for ( ....) {
 *       template.submit(new Runnable() {})
 *    }
 * 
 *    List<?> result = template.waitForResult();
 *    // do result
 * } finally {
 *    template.clear();
 * }
 * 
 * 注意：该模板工程，不支持多业务并发调用，会出现数据混乱
 * </pre>
 */
public class ExecutorTemplate {

    private volatile ThreadPoolExecutor executor = null;
    private volatile List<Future>       futures  = null;

    public ExecutorTemplate(ThreadPoolExecutor executor){
        this.futures = Collections.synchronizedList(new ArrayList<>());
        this.executor = executor;
    }

    public void submit(Runnable task) {
        Future future = executor.submit(task, null);
        futures.add(future);
        check(future);
    }

    public void submit(Callable task) {
        Future future = executor.submit(task);
        futures.add(future);
        check(future);
    }

    private void check(Future future) {
        if (future.isDone()) {
            // 立即判断一次，因为使用了CallerRun可能当场跑出结果，针对有异常时快速响应，而不是等跑完所有的才抛异常
            try {
                future.get();
            } catch (Throwable e) {
                // 取消完之后立马退出
                cacelAllFutures();
                throw new RuntimeException(e);
            }
        }
    }

    public synchronized List<?> waitForResult() {
        List result = new ArrayList();
        RuntimeException exception = null;

        for (Future future : futures) {
            try {
                result.add(future.get());
            } catch (Throwable e) {
                exception = new RuntimeException(e);
                // 如何一个future出现了异常，就退出
                break;
            }
        }

        if (exception != null) {
            cacelAllFutures();
            throw exception;
        } else {
            return result;
        }
    }

    public void cacelAllFutures() {
        for (Future future : futures) {
            if (!future.isDone() && !future.isCancelled()) {
                future.cancel(true);
            }
        }
    }

    public void clear() {
        futures.clear();
    }

}

ExecutorTemplate template = new ExecutorTemplate(sendPartitionExecutor);
for (int i = 0; i < length; i++) {
    com.alibaba.otter.canal.protocol.Message dataPartition = messages[i];
    if (dataPartition != null) {
        final int index = i;
        template.submit(() -> {
            Message data = new Message(topicName,
                ((RocketMQProducerConfig) this.mqProperties).getTag(),
                CanalMessageSerializerUtil.serializer(dataPartition,
                    mqProperties.isFilterTransactionEntry()));
            sendMessage(data, index);
        });
    }
}
// 等所有分片发送完毕
template.waitForResult();

/**
 * 服务端running状态信息
 * 
 * @author jianghang 2012-11-22 下午03:11:30
 * @version 1.0.0
 */
public class ServerRunningData implements Serializable {

    private static final long serialVersionUID = 92260481691855281L;

    @Deprecated
    private Long              cid;
    private String            address;
    private boolean           active           = true;

    public ServerRunningData(){
    }

    public ServerRunningData(String address){
        this.address = address;
    }

    public Long getCid() {
        return cid;
    }

    public void setCid(Long cid) {
        this.cid = cid;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public boolean isActive() {
        return active;
    }

    public void setActive(boolean active) {
        this.active = active;
    }

    public String toString() {
        return ToStringBuilder.reflectionToString(this, CanalToStringStyle.DEFAULT_STYLE);
    }

}

/**
 * 触发一下mainstem发生切换
 * 
 * @author jianghang 2012-9-11 下午02:26:03
 * @version 1.0.0
 */
public interface ServerRunningListener {

    /**
     * 启动时回调做点事情
     */
    public void processStart();

    /**
     * 关闭时回调做点事情
     */
    public void processStop();

    /**
     * 触发现在轮到自己做为active，需要载入上一个active的上下文数据
     */
    public void processActiveEnter();

    /**
     * 触发一下当前active模式失败
     */
    public void processActiveExit();

}

/**
 * 针对server的running节点控制
 * 
 * @author jianghang 2012-11-22 下午02:59:42
 * @version 1.0.0
 */
public class ServerRunningMonitor extends AbstractCanalLifeCycle {

    private static final Logger        logger       = LoggerFactory.getLogger(ServerRunningMonitor.class);
    private ZkClientx                  zkClient;
    private String                     destination;
    private IZkDataListener            dataListener;
    private BooleanMutex               mutex        = new BooleanMutex(false);
    private volatile boolean           release      = false;
    // 当前服务节点状态信息
    private ServerRunningData          serverData;
    // 当前实际运行的节点状态信息
    private volatile ServerRunningData activeData;
    private ScheduledExecutorService   delayExecutor;
    private int                        delayTime    = 5;
    private ServerRunningListener      listener;

    public ServerRunningMonitor(ServerRunningData serverData){
        this();
        this.serverData = serverData;
    }

    public ServerRunningMonitor(){
        // 创建父节点
        dataListener = new IZkDataListener() {

            public void handleDataChange(String dataPath, Object data) throws Exception {
                MDC.put("destination", destination);
                ServerRunningData runningData = JsonUtils.unmarshalFromByte((byte[]) data, ServerRunningData.class);
                if (!isMine(runningData.getAddress())) {
                    mutex.set(false);
                }

                if (!runningData.isActive() && isMine(runningData.getAddress())) { // 说明出现了主动释放的操作，并且本机之前是active
                    releaseRunning();// 彻底释放mainstem
                }

                activeData = (ServerRunningData) runningData;
            }

            public void handleDataDeleted(String dataPath) throws Exception {
                MDC.put("destination", destination);
                mutex.set(false);
                if (!release && activeData != null && isMine(activeData.getAddress())) {
                    // 如果上一次active的状态就是本机，则即时触发一下active抢占
                    initRunning();
                } else {
                    // 否则就是等待delayTime，避免因网络瞬端或者zk异常，导致出现频繁的切换操作
                    delayExecutor.schedule(() -> initRunning(), delayTime, TimeUnit.SECONDS);
                }
            }

        };

    }

    public void init() {
        processStart();
    }

    public synchronized void start() {
        super.start();
        try {
            processStart();
            if (zkClient != null) {
                delayExecutor = Executors.newScheduledThreadPool(1);
                // 如果需要尽可能释放instance资源，不需要监听running节点，不然即使stop了这台机器，另一台机器立马会start
                String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
                zkClient.subscribeDataChanges(path, dataListener);

                initRunning();
            } else {
                processActiveEnter();// 没有zk，直接启动
            }
        } catch (Exception e) {
            logger.error("start failed", e);
            // 没有正常启动，重置一下状态，避免干扰下一次start
            stop();
        }

    }

    public boolean release() {
        if (zkClient != null) {
            releaseRunning(); // 尝试一下release
            return true;
        } else {
            processActiveExit(); // 没有zk，直接退出
            return false;
        }
    }

    public synchronized void stop() {
        super.stop();

        if (zkClient != null) {
            String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
            zkClient.unsubscribeDataChanges(path, dataListener);
            if (delayExecutor != null) {
                delayExecutor.shutdown();
                delayExecutor = null;
            }

            releaseRunning(); // 尝试一下release
        } else {
            processActiveExit(); // 没有zk，直接启动
        }
        processStop();
    }

    private void initRunning() {
        if (!isStart()) {
            return;
        }

        String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
        // 序列化
        byte[] bytes = JsonUtils.marshalToByte(serverData);
        try {
            mutex.set(false);
            zkClient.create(path, bytes, CreateMode.EPHEMERAL);
            activeData = serverData;
            processActiveEnter();// 触发一下事件
            mutex.set(true);
            release = false;
        } catch (ZkNodeExistsException e) {
            bytes = zkClient.readData(path, true);
            if (bytes == null) {// 如果不存在节点，立即尝试一次
                initRunning();
            } else {
                activeData = JsonUtils.unmarshalFromByte(bytes, ServerRunningData.class);
            }
        } catch (ZkNoNodeException e) {
            zkClient.createPersistent(ZookeeperPathUtils.getDestinationPath(destination), true); // 尝试创建父节点
            initRunning();
        }
    }

    /**
     * 阻塞等待自己成为active，如果自己成为active，立马返回
     * 
     * @throws InterruptedException
     */
    public void waitForActive() throws InterruptedException {
        initRunning();
        mutex.get();
    }

    /**
     * 检查当前的状态
     */
    public boolean check() {
        String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
        try {
            byte[] bytes = zkClient.readData(path);
            ServerRunningData eventData = JsonUtils.unmarshalFromByte(bytes, ServerRunningData.class);
            activeData = eventData;// 更新下为最新值
            // 检查下nid是否为自己
            boolean result = isMine(activeData.getAddress());
            if (!result) {
                logger.warn("canal is running in node[{}] , but not in node[{}]",
                    activeData.getAddress(),
                    serverData.getAddress());
            }
            return result;
        } catch (ZkNoNodeException e) {
            logger.warn("canal is not run any in node");
            return false;
        } catch (ZkInterruptedException e) {
            logger.warn("canal check is interrupt");
            Thread.interrupted();// 清除interrupt标记
            return check();
        } catch (ZkException e) {
            logger.warn("canal check is failed");
            return false;
        }
    }

    private boolean releaseRunning() {
        if (check()) {
            release = true;
            String path = ZookeeperPathUtils.getDestinationServerRunning(destination);
            zkClient.delete(path);
            mutex.set(false);
            processActiveExit();
            return true;
        }

        return false;
    }

    // ====================== helper method ======================

    private boolean isMine(String address) {
        return address.equals(serverData.getAddress());
    }

    private void processStart() {
        if (listener != null) {
            try {
                listener.processStart();
            } catch (Exception e) {
                logger.error("processStart failed", e);
            }
        }
    }

    private void processStop() {
        if (listener != null) {
            try {
                listener.processStop();
            } catch (Exception e) {
                logger.error("processStop failed", e);
            }
        }
    }

    private void processActiveEnter() {
        if (listener != null) {
            listener.processActiveEnter();
        }
    }

    private void processActiveExit() {
        if (listener != null) {
            try {
                listener.processActiveExit();
            } catch (Exception e) {
                logger.error("processActiveExit failed", e);
            }
        }
    }

    public void setListener(ServerRunningListener listener) {
        this.listener = listener;
    }

    // ===================== setter / getter =======================

    public void setDelayTime(int delayTime) {
        this.delayTime = delayTime;
    }

    public void setServerData(ServerRunningData serverData) {
        this.serverData = serverData;
    }

    public void setDestination(String destination) {
        this.destination = destination;
    }

    public void setZkClient(ZkClientx zkClient) {
        this.zkClient = zkClient;
    }

}

/**
 * {@linkplain ServerRunningMonitor}管理容器，使用static进行数据全局共享
 * 
 * @author jianghang 2012-12-3 下午09:32:06
 * @version 1.0.0
 */
public class ServerRunningMonitors {

    private static ServerRunningData serverData;
    private static Map               runningMonitors; // <String,
                                                      // ServerRunningMonitor>

    public static ServerRunningData getServerData() {
        return serverData;
    }

    public static Map<String, ServerRunningMonitor> getRunningMonitors() {
        return runningMonitors;
    }

    public static ServerRunningMonitor getRunningMonitor(String destination) {
        return (ServerRunningMonitor) runningMonitors.get(destination);
    }

    public static void setServerData(ServerRunningData serverData) {
        ServerRunningMonitors.serverData = serverData;
    }

    public static void setRunningMonitors(Map runningMonitors) {
        ServerRunningMonitors.runningMonitors = runningMonitors;
    }

}

ServerRunningMonitor runningMonitor = ServerRunningMonitors.getRunningMonitor(destination);
if (!config.getLazy() && !runningMonitor.isStart()) {
    runningMonitor.start();
}