infra/notification/impl/src/main/java/io/fd/honeycomb/v3po/notification/impl/NotificationProducerTracker.java

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package io.fd.honeycomb.v3po.notification.impl;
  17
  18 import static com.google.common.base.Preconditions.checkState;
  19
  20 import com.google.common.collect.Sets;
  21 import io.fd.honeycomb.v3po.notification.ManagedNotificationProducer;
  22 import io.fd.honeycomb.v3po.notification.NotificationCollector;
  23 import java.util.HashSet;
  24 import java.util.Set;
  25 import java.util.stream.Collectors;
  26 import javax.annotation.Nonnull;
  27 import javax.annotation.concurrent.ThreadSafe;
  28 import org.opendaylight.controller.md.sal.dom.spi.DOMNotificationSubscriptionListener;
  29 import org.opendaylight.controller.md.sal.dom.spi.DOMNotificationSubscriptionListenerRegistry;
  30 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  31 import org.opendaylight.yangtools.yang.common.QName;
  32 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 /**
  37  * Starts & stops notification producer dependencies on demand.
  38  * Uses {@link DOMNotificationSubscriptionListenerRegistry} to receive subscription change notifications.
  39  */
  40 @ThreadSafe
  41 public final class NotificationProducerTracker
  42     implements DOMNotificationSubscriptionListener, AutoCloseable {
  43
  44     private static final Logger LOG = LoggerFactory.getLogger(NotificationProducerTracker.class);
  45
  46     private final ListenerRegistration<NotificationProducerTracker> subscriptionListener;
  47     private final NotificationProducerRegistry registry;
  48     private final NotificationCollector collector;
  49
  50     private final Set<ManagedNotificationProducer> alreadyStartedProducers = new HashSet<>();
  51
  52     public NotificationProducerTracker(@Nonnull final NotificationProducerRegistry registry,
  53                                        @Nonnull final NotificationCollector collector,
  54                                        @Nonnull final DOMNotificationSubscriptionListenerRegistry notificationRouter) {
  55         this.registry = registry;
  56         this.collector = collector;
  57         this.subscriptionListener = notificationRouter.registerSubscriptionListener(this);
  58     }
  59
  60     @Override
  61     public synchronized void onSubscriptionChanged(final Set<SchemaPath> set) {
  62         LOG.debug("Subscriptions changed. Current subscriptions: {}", set);
  63         final Set<QName> currentSubscriptions = set.stream().map(SchemaPath::getLastComponent).collect(Collectors.toSet());
  64         final Set<QName> startedQNames = getStartedQNames(alreadyStartedProducers);
  65         final Sets.SetView<QName> newSubscriptions = Sets.difference(currentSubscriptions, startedQNames);
  66         LOG.debug("Subscriptions changed. New subscriptions: {}", newSubscriptions);
  67         final Sets.SetView<QName> deletedSubscriptions = Sets.difference(startedQNames, currentSubscriptions);
  68         LOG.debug("Subscriptions changed. Deleted subscriptions: {}", deletedSubscriptions);
  69
  70         newSubscriptions.stream().forEach(newSub -> {
  71             if(!registry.getNotificationQNameToProducer().containsKey(newSub)) {
  72                 return;
  73             }
  74             final ManagedNotificationProducer producer = registry.getNotificationQNameToProducer().get(newSub);
  75             if(alreadyStartedProducers.contains(producer)) {
  76                 return;
  77             }
  78             LOG.debug("Starting notification producer: {}", producer);
  79             producer.start(collector);
  80             alreadyStartedProducers.add(producer);
  81         });
  82
  83         deletedSubscriptions.stream().forEach(newSub -> {
  84             checkState(registry.getNotificationQNameToProducer().containsKey(newSub));
  85             final ManagedNotificationProducer producer = registry.getNotificationQNameToProducer().get(newSub);
  86             checkState(alreadyStartedProducers.contains(producer));
  87             LOG.debug("Stopping notification producer: {}", producer);
  88             producer.stop();
  89             alreadyStartedProducers.remove(producer);
  90         });
  91
  92     }
  93
  94     private Set<QName> getStartedQNames(final Set<ManagedNotificationProducer> alreadyStartedProducers) {
  95         return alreadyStartedProducers.stream()
  96             .flatMap(p -> registry.getNotificationProducerQNames().get(p).stream())
  97             .collect(Collectors.toSet());
  98     }
  99
 100     @Override
 101     public synchronized void close() throws Exception {
 102         LOG.trace("Closing");
 103         subscriptionListener.close();
 104         // Stop all producers
 105         LOG.debug("Stopping all producers: {}", alreadyStartedProducers);
 106         alreadyStartedProducers.forEach(ManagedNotificationProducer::stop);
 107         alreadyStartedProducers.clear();
 108     }
 109 }