private ScheduleInfoCache(TopicTalosResourceName topicTalosResourceName,
    TalosClientConfig talosClientConfig, MessageService.Iface messageClient){
  this.topicTalosResourceName = topicTalosResourceName;
  this.messageClient = messageClient;
  this.talosClientConfig = talosClientConfig;
  this.isAutoLocation = false;
  this.clientNum = new AtomicInteger(0);

  GetScheduleInfoScheduleExecutor = Executors.newSingleThreadScheduledExecutor(
      new NamedThreadFactory("talos-ScheduleInfoCache"));
  GetScheduleInfoExecutor = new ThreadPoolExecutor(1, 1,
      0L, TimeUnit.MILLISECONDS,
      new LinkedBlockingQueue<Runnable>(1), new DiscardPolicy());

  LOG.warn("SimpleProducer or SimpleConsumer was built using improperly constructed function."
      + "Auto location was forbidden");
}
 

public MetricFetcher() {
    int cores = Runtime.getRuntime().availableProcessors() * 2;
    long keepAliveTime = 0;
    int queueSize = 2048;
    RejectedExecutionHandler handler = new DiscardPolicy();
    fetchService = new ThreadPoolExecutor(cores, cores,
        keepAliveTime, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(queueSize),
        new NamedThreadFactory("sentinel-dashboard-metrics-fetchService"), handler);
    fetchWorker = new ThreadPoolExecutor(cores, cores,
        keepAliveTime, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(queueSize),
        new NamedThreadFactory("sentinel-dashboard-metrics-fetchWorker"), handler);
    IOReactorConfig ioConfig = IOReactorConfig.custom()
        .setConnectTimeout(3000)
        .setSoTimeout(3000)
        .setIoThreadCount(Runtime.getRuntime().availableProcessors() * 2)
        .build();

    httpclient = HttpAsyncClients.custom()
        .setRedirectStrategy(new DefaultRedirectStrategy() {
            @Override
            protected boolean isRedirectable(final String method) {
                return false;
            }
        }).setMaxConnTotal(4000)
        .setMaxConnPerRoute(1000)
        .setDefaultIOReactorConfig(ioConfig)
        .build();
    httpclient.start();
    start();
}
 

public MetricFetcher() {
    int cores = Runtime.getRuntime().availableProcessors() * 2;
    long keepAliveTime = 0;
    int queueSize = 2048;
    RejectedExecutionHandler handler = new DiscardPolicy();
    fetchService = new ThreadPoolExecutor(cores, cores,
        keepAliveTime, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(queueSize),
        new NamedThreadFactory("sentinel-dashboard-metrics-fetchService"), handler);
    fetchWorker = new ThreadPoolExecutor(cores, cores,
        keepAliveTime, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(queueSize),
        new NamedThreadFactory("sentinel-dashboard-metrics-fetchWorker"), handler);
    IOReactorConfig ioConfig = IOReactorConfig.custom()
        .setConnectTimeout(3000)
        .setSoTimeout(3000)
        .setIoThreadCount(Runtime.getRuntime().availableProcessors() * 2)
        .build();

    httpclient = HttpAsyncClients.custom()
        .setRedirectStrategy(new DefaultRedirectStrategy() {
            @Override
            protected boolean isRedirectable(final String method) {
                return false;
            }
        }).setMaxConnTotal(4000)
        .setMaxConnPerRoute(1000)
        .setDefaultIOReactorConfig(ioConfig)
        .build();
    httpclient.start();
    start();
}
 

private ScheduleInfoCache(TopicTalosResourceName topicTalosResourceName,
    TalosClientConfig talosClientConfig, MessageService.Iface messageClient,
    TalosClientFactory talosClientFactory) {
  this.topicTalosResourceName = topicTalosResourceName;
  this.talosClientConfig = talosClientConfig;
  this.isAutoLocation = talosClientConfig.isAutoLocation();
  this.readWriteLock = new ReentrantReadWriteLock();
  this.messageClient = messageClient;
  this.talosClientFactory = talosClientFactory;
  this.messageClientMap = new HashMap<String, MessageService.Iface>();
  this.clientNum = new AtomicInteger(0);

  // GetScheduleInfoScheduleExecutor for Schedule get work, cause ScheduledExecutorService
  // use DelayedWorkQueue storage its task, which is unbounded. To private OOM, use
  // GetScheduleInfoExecutor execute task when transfered, setting Queue size as 2.
  GetScheduleInfoScheduleExecutor = Executors.newSingleThreadScheduledExecutor(
      new NamedThreadFactory("talos-ScheduleInfoCache"));
  GetScheduleInfoExecutor = new ThreadPoolExecutor(1, 1,
      0L, TimeUnit.MILLISECONDS,
      new LinkedBlockingQueue<Runnable>(1), new DiscardPolicy());

  LOG.info(this.isAutoLocation ? "Auto location is enabled for request of " + topicTalosResourceName
      : "Auto location is forbidden for request of " + topicTalosResourceName);

  try {
    //get and update scheduleInfoMap
    getScheduleInfo(topicTalosResourceName);
  } catch (Throwable throwable) {
    LOG.error("Exception in GetScheduleInfoTask: ", throwable);
    if (Utils.isTopicNotExist(throwable)) {
      return;
    }
  }
}
 

@Test
public void givenDiscardPolicy_WhenSaturated_ThenExecutorDiscardsTheNewTask() throws InterruptedException {
    executor = new ThreadPoolExecutor(1, 1, 0, MILLISECONDS, new SynchronousQueue<>(), new DiscardPolicy());
    executor.execute(() -> waitFor(100));

    BlockingQueue<String> queue = new LinkedBlockingDeque<>();
    executor.execute(() -> queue.offer("Result"));

    assertThat(queue.poll(200, MILLISECONDS)).isNull();
}