restconf/sal-rest-connector/src/main/java/org/opendaylight/netconf/sal/streams/listeners/AbstractCommonSubscriber.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.netconf.sal.streams.listeners;
   9
  10 import com.google.common.eventbus.AsyncEventBus;
  11 import com.google.common.eventbus.EventBus;
  12 import io.netty.channel.Channel;
  13 import io.netty.util.internal.ConcurrentSet;
  14 import java.util.Set;
  15 import java.util.concurrent.Executors;
  16 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  17 import org.slf4j.Logger;
  18 import org.slf4j.LoggerFactory;
  19
  20 /**
  21  * Features of subscribing part of both notifications.
  22  */
  23 abstract class AbstractCommonSubscriber extends AbstractQueryParams implements BaseListenerInterface {
  24
  25     private static final Logger LOG = LoggerFactory.getLogger(AbstractCommonSubscriber.class);
  26
  27     private final Set<Channel> subscribers = new ConcurrentSet<>();
  28     private final EventBus eventBus;
  29
  30     @SuppressWarnings("rawtypes")
  31     private EventBusChangeRecorder eventBusChangeRecorder;
  32     @SuppressWarnings("rawtypes")
  33     private ListenerRegistration registration;
  34
  35     /**
  36      * Creating {@link EventBus}.
  37      */
  38     protected AbstractCommonSubscriber() {
  39         this.eventBus = new AsyncEventBus(Executors.newSingleThreadExecutor());
  40     }
  41
  42     @Override
  43     public final boolean hasSubscribers() {
  44         return !this.subscribers.isEmpty();
  45     }
  46
  47     @Override
  48     public final Set<Channel> getSubscribers() {
  49         return this.subscribers;
  50     }
  51
  52     @Override
  53     public final void close() throws Exception {
  54         this.registration.close();
  55         this.registration = null;
  56
  57         deleteDataInDS();
  58         unregister();
  59     }
  60
  61     /**
  62      * Creates event of type {@link EventType#REGISTER}, set {@link Channel}
  63      * subscriber to the event and post event into event bus.
  64      *
  65      * @param subscriber
  66      *            Channel
  67      */
  68     public void addSubscriber(final Channel subscriber) {
  69         if (!subscriber.isActive()) {
  70             LOG.debug("Channel is not active between websocket server and subscriber {}" + subscriber.remoteAddress());
  71         }
  72         final Event event = new Event(EventType.REGISTER);
  73         event.setSubscriber(subscriber);
  74         this.eventBus.post(event);
  75     }
  76
  77     /**
  78      * Creates event of type {@link EventType#DEREGISTER}, sets {@link Channel}
  79      * subscriber to the event and posts event into event bus.
  80      *
  81      * @param subscriber subscriber channel
  82      */
  83     public void removeSubscriber(final Channel subscriber) {
  84         LOG.debug("Subscriber {} is removed.", subscriber.remoteAddress());
  85         final Event event = new Event(EventType.DEREGISTER);
  86         event.setSubscriber(subscriber);
  87         this.eventBus.post(event);
  88     }
  89
  90     /**
  91      * Sets {@link ListenerRegistration} registration.
  92      *
  93      * @param registration
  94      *            DOMDataChangeListener registration
  95      */
  96     @SuppressWarnings("rawtypes")
  97     public void setRegistration(final ListenerRegistration registration) {
  98         this.registration = registration;
  99     }
 100
 101     /**
 102      * Checks if {@link ListenerRegistration} registration exist.
 103      *
 104      * @return True if exist, false otherwise.
 105      */
 106     public boolean isListening() {
 107         return this.registration != null;
 108     }
 109
 110     /**
 111      * Creating and registering {@link EventBusChangeRecorder} of specific
 112      * listener on {@link EventBus}.
 113      *
 114      * @param listener
 115      *            specific listener of notifications
 116      */
 117     @SuppressWarnings({ "unchecked", "rawtypes" })
 118     protected <T extends BaseListenerInterface> void register(final T listener) {
 119         this.eventBusChangeRecorder = new EventBusChangeRecorder(listener);
 120         this.eventBus.register(this.eventBusChangeRecorder);
 121     }
 122
 123     /**
 124      * Post event to event bus.
 125      *
 126      * @param event
 127      *            data of incoming notifications
 128      */
 129     protected void post(final Event event) {
 130         this.eventBus.post(event);
 131     }
 132
 133     /**
 134      * Removes all subscribers and unregisters event bus change recorder form
 135      * event bus.
 136      */
 137     protected void unregister() {
 138         this.subscribers.clear();
 139         this.eventBus.unregister(this.eventBusChangeRecorder);
 140     }
 141 }