+package org.argeo.cms.internal.runtime;
+
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.Flow;
+import java.util.concurrent.Flow.Subscription;
+import java.util.concurrent.SubmissionPublisher;
+
+import org.argeo.api.cms.CmsEventBus;
+import org.argeo.api.cms.CmsEventSubscriber;
+import org.argeo.api.cms.CmsLog;
+
+public class CmsEventBusImpl implements CmsEventBus {
+ private final CmsLog log = CmsLog.getLog(CmsEventBus.class);
+
+ // CMS events
+ private Map<String, SubmissionPublisher<Map<String, Object>>> topics = new TreeMap<>();
+// private IdentityHashMap<CmsEventSubscriber, List<CmsEventFlowSubscriber>> subscriptions = new IdentityHashMap<>();
+
+ /*
+ * CMS Events
+ */
+ @Override
+ public void sendEvent(String topic, Map<String, Object> event) {
+ SubmissionPublisher<Map<String, Object>> publisher = topics.get(topic);
+ if (publisher == null)
+ return; // no one is interested
+ publisher.submit(event);
+ }
+
+ @Override
+ public void addEventSubscriber(String topic, CmsEventSubscriber subscriber) {
+ synchronized (topics) {
+ if (!topics.containsKey(topic))
+ topics.put(topic, new SubmissionPublisher<>());
+ }
+ SubmissionPublisher<Map<String, Object>> publisher = topics.get(topic);
+ CmsEventFlowSubscriber flowSubscriber = new CmsEventFlowSubscriber(topic, subscriber);
+ publisher.subscribe(flowSubscriber);
+ }
+
+ @Override
+ public void removeEventSubscriber(String topic, CmsEventSubscriber subscriber) {
+ SubmissionPublisher<Map<String, Object>> publisher = topics.get(topic);
+ if (publisher == null) {
+ log.error("There should be an event topic " + topic);
+ return;
+ }
+ for (Flow.Subscriber<? super Map<String, Object>> flowSubscriber : publisher.getSubscribers()) {
+ if (flowSubscriber instanceof CmsEventFlowSubscriber)
+ ((CmsEventFlowSubscriber) flowSubscriber).unsubscribe();
+ }
+ synchronized (topics) {
+ if (!publisher.hasSubscribers()) {
+ publisher.close();
+ topics.remove(topic);
+ }
+ }
+ }
+
+ static class CmsEventFlowSubscriber implements Flow.Subscriber<Map<String, Object>> {
+ private String topic;
+ private CmsEventSubscriber eventSubscriber;
+
+ private Subscription subscription;
+
+ public CmsEventFlowSubscriber(String topic, CmsEventSubscriber eventSubscriber) {
+ this.topic = topic;
+ this.eventSubscriber = eventSubscriber;
+ }
+
+ @Override
+ public void onSubscribe(Subscription subscription) {
+ this.subscription = subscription;
+ subscription.request(1);
+ }
+
+ @Override
+ public void onNext(Map<String, Object> item) {
+ eventSubscriber.onEvent(topic, item);
+ subscription.request(1);
+ }
+
+ @Override
+ public void onError(Throwable throwable) {
+ // TODO Auto-generated method stub
+
+ }
+
+ @Override
+ public void onComplete() {
+ // TODO Auto-generated method stub
+
+ }
+
+ void unsubscribe() {
+ if (subscription != null)
+ subscription.cancel();
+ else
+ throw new IllegalStateException("No subscription to cancel");
+ }
+
+ }
+
+}