public void close() {
		for (FutureTask<TairClient> task : clients.values()) {	
			if (task.isDone() || !task.cancel(true)) {
				TairClient client = null;
				try {
					client = task.get();
				} catch (InterruptedException e) {
					LOGGER.warn(e);
				} catch (ExecutionException e) {
					LOGGER.warn(e);
				} catch (CancellationException e){
				}
				client.close();
			}
		}
		clients.clear();
	}