public class ZKLock {
	
	
	//提前建立好鎖物件的結點"/lock" CreateMode.PERSISTENT
	public static final String LOCK_ZNODE = "/lock";
	//分散式鎖實現分散式seq生成
	public static class Task2 implements Runnable, IZkChildListener {
	 
	    private final String taskName;
	 
	    private final ZkClient zkClient;
	 
	    private final String lockPrefix = "/loc";
	 
	    private final String selfZnode;
	 
	    public Task2(String taskName) {
	        this.taskName = taskName;
	        zkClient = new ZkClient("192.168.190.36:2181", 30000, 50000);
	        selfZnode = zkClient.createEphemeralSequential(LOCK_ZNODE + lockPrefix, new byte[0]);
	    }
	 
	    @Override
	    public void run() {

	    	  createSeq();
	    }	 
	 
	    private void createSeq() {
	        Stat stat = new Stat();
	        byte[] oldData = zkClient.readData(LOCK_ZNODE, stat);
	        byte[] newData = update(oldData);
	        zkClient.writeData(LOCK_ZNODE, newData);
	        System.out.println(taskName + selfZnode + " obtain seq=" + new String(newData));
	    }
	 
	    private byte[] update(byte[] currentData) {
	        String s = new String(currentData);
	        int d = Integer.parseInt(s);
	        d = d + 1;
	        s = String.valueOf(d);
	        return s.getBytes();
	    }

		@Override
		public void handleChildChange(String parentPath,
				List<String> currentChildren) throws Exception {
			// TODO Auto-generated method stub
			
		}	 
	   
	}
	

	public static void main(String[] args) {
	
				final ExecutorService service = Executors.newFixedThreadPool(20);
				 
				for (int i = 0; i < 10; i++) {
				    service.execute(new Task2("[Concurrent-" + i + "]"));
				}
				service.shutdown();
	}

}