基于异步调度的任务取消行为

基于ScheduledFuture来完成任务取消

代码如下：

public class ScheduledExecutorPingSender  implements MqttPingSender {

    private static final String CLASS_NAME = ScheduledExecutorPingSender.class.getName();
    private final Logger log = LoggerFactory.getLogger(LoggerFactory.MQTT_CLIENT_MSG_CAT,CLASS_NAME);


    private ClientComms   comms;
    private ScheduledExecutorService  executorService;
    private ScheduledFuture  scheduledFuture;
    private String clientid;


    public ScheduledExecutorPingSender(ScheduledExecutorService executorService){
        if(executorService == null){
            throw new IllegalArgumentException("ExecutorService cannot be null");
        }
        this.executorService = executorService;
    }

    @Override
    public void init(ClientComms comms) {
        if(comms == null){
            throw  new IllegalArgumentException("ClientComms cannot be null");
        }
        this.comms = comms;
        clientid = comms.getClient().getClientId();
    }

    @Override
    public void start() {
        final String methodName = "start";

        log.fine(CLASS_NAME,methodName,"659",new Object[]{clientid});
        //第一个心跳间隔过完之后，要检查ping
        schedule(comms.getKeepAlive());
    }

    @Override
    public void stop() {
        final String methodName = "stop";
        log.fine(CLASS_NAME,methodName,"661",null);
        if(scheduledFuture !=null){
            //基于异步调度的任务取消行为
            scheduledFuture.cancel(true);
        }
    }

    @Override
    public void schedule(long delayInMillseconds) {
        scheduledFuture = executorService.schedule(new PingRunnable(),delayInMillseconds, TimeUnit.MILLISECONDS);
    }

    private class PingRunnable implements Runnable{

        private static final String methodName = "PingTask.run";


        @Override
        public void run() {
            String originalThreadName = Thread.currentThread().getName();
            //设置当前线程的名称
            Thread.currentThread().setName("MQTT Ping: " + clientid);

            log.fine(CLASS_NAME,methodName,"660",new Object[]{Long.valueOf(System.nanoTime())});
            comms.checkForActivity();
            Thread.currentThread().setName(originalThreadName);
        }
    }
}