org.osgi.framework.hooks.bundle.EventHook#org.osgi.framework.hooks.service.EventListenerHook源码实例Demo

/**
 * Workaround https://issues.apache.org/jira/browse/KARAF-4899 by
 * re-adding probe bundle to root region before any service lookup
 * (avoids spurious service lookup issues due to region filtering)
 */
private void installRegionWorkaround(final BundleContext context) {
  Map<String, ?> maxRanking = singletonMap(SERVICE_RANKING, Integer.MAX_VALUE);

  // add probe to root region on install
  context.registerService(EventHook.class,
      (event, contexts) -> {
        if (event.getType() == BundleEvent.INSTALLED) {
          fixProbeRegion(event.getBundle());
        }
      }, new Hashtable<>(maxRanking));

  // add probe to root region whenever a service it's listening to changes
  context.registerService(EventListenerHook.class,
      (event, listeners) -> {
        if (((String[]) event.getServiceReference().getProperty(Constants.OBJECTCLASS))[0].contains("pax.exam")) {
          listeners.keySet().stream().map(BundleContext::getBundle).forEach(this::fixProbeRegion);
        }
      }, new Hashtable<>(maxRanking));

  // add probe to root region whenever it's directly looking up a service
  context.registerService(FindHook.class,
      (findContext, name, filter, allServices, references) -> {
        if ((name != null && name.contains("pax.exam")) || (filter != null && filter.contains("pax.exam"))) {
          fixProbeRegion(findContext.getBundle());
        }
      }, new Hashtable<>(maxRanking));
}