com.codahale.metrics.MetricRegistry#removeMatching ( )源码实例Demo

/**
 * This method starts a separate thread that listens to key expirations events.
 *
 * @param sessionManager
 */
@Override
public void setSessionManager(final SessionManager sessionManager) {
  this.sessionManager = sessionManager;
  MetricRegistry metrics = sessionManager.getMetrics();
  if (metrics != null) {
    // Cleanup old metrics related to this namespace
    metrics.removeMatching(new MetricFilter() {
      @Override
      public boolean matches(String name, Metric metric) {
        return name.startsWith(name(RedisConfiguration.METRIC_PREFIX, "redis"));
      }
    });
    if (sticky) {
      failoverMetrics = metrics.meter(name(RedisConfiguration.METRIC_PREFIX, namespace, "redis", "failover"));
    }

    redis.startMonitoring(metrics);
  }
  expirationManager.startExpiredSessionsTask(sessionManager);
}
 

public int unregisterGauges(String registryName, String tagSegment) {
  if (tagSegment == null) {
    return 0;
  }
  MetricRegistry registry = registry(registryName);
  if (registry == null) return 0;
  AtomicInteger removed = new AtomicInteger();
  registry.removeMatching((name, metric) -> {
    if (metric instanceof GaugeWrapper) {
      @SuppressWarnings({"rawtypes"})
      GaugeWrapper wrapper = (GaugeWrapper) metric;
      boolean toRemove = wrapper.getTag().contains(tagSegment);
      if (toRemove) {
        removed.incrementAndGet();
      }
      return toRemove;
    }
    return false;

  });
  return removed.get();
}
 

public static void shutdown(MetricRegistry registry) {
  registry.removeMatching((name, metric) -> true);
}
 

/**
 * Register a gauge.
 * That is, a number of some sort that gets polled at intervals, and
 * reported to Graphite. For example, the number of known modules.
 * Call like this:
 *     DropwizardHelper.registerGauge("moduleCount", () -> modules.size());
 *
 * @param key The key for the metric to report
 * @param g A Gauge with a lambda to get the value
 */
public static void registerGauge(String key, Gauge g) {
  try {
    MetricRegistry reg = SharedMetricRegistries.getOrCreate("okapi");
    reg.removeMatching((String name, Metric metric) -> key.equals(name));
    reg.register(key, g);
  } catch (Exception e) {
    logger.warn("registerGauge {}", e.getMessage(), e);
  }
}