openstack/net-virt/src/main/java/org/opendaylight/ovsdb/openstack/netvirt/impl/EventDispatcherImpl.java

   1 /*
   2  * Copyright (C) 2014 Red Hat, Inc.
   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  * Authors : Dave Tucker, Flavio Fernandes
   9  */
  10
  11 package org.opendaylight.ovsdb.openstack.netvirt.impl;
  12
  13 import org.opendaylight.ovsdb.openstack.netvirt.AbstractEvent;
  14 import org.opendaylight.ovsdb.openstack.netvirt.AbstractHandler;
  15 import org.opendaylight.ovsdb.openstack.netvirt.ConfigInterface;
  16 import org.opendaylight.ovsdb.openstack.netvirt.api.Constants;
  17 import org.opendaylight.ovsdb.openstack.netvirt.api.EventDispatcher;
  18
  19 import org.osgi.framework.BundleContext;
  20 import org.osgi.framework.ServiceReference;
  21 import org.slf4j.Logger;
  22 import org.slf4j.LoggerFactory;
  23
  24 import java.util.concurrent.BlockingQueue;
  25 import java.util.concurrent.ExecutorService;
  26 import java.util.concurrent.Executors;
  27 import java.util.concurrent.LinkedBlockingQueue;
  28 import java.util.concurrent.TimeUnit;
  29
  30 public class EventDispatcherImpl implements EventDispatcher, ConfigInterface {
  31     static final Logger logger = LoggerFactory.getLogger(EventDispatcher.class);
  32     private ExecutorService eventHandler;
  33     private volatile BlockingQueue<AbstractEvent> events;
  34     private AbstractHandler[] handlers;
  35
  36     public EventDispatcherImpl() {
  37         events = new LinkedBlockingQueue<>();
  38         handlers = new AbstractHandler[AbstractEvent.HandlerType.size];
  39         eventHandler = Executors.newSingleThreadExecutor();
  40         start();
  41     }
  42
  43     void start() {
  44         eventHandler.submit(new Runnable()  {
  45             @Override
  46             public void run() {
  47                 Thread t = Thread.currentThread();
  48                 t.setName("EventDispatcherImpl");
  49                 logger.info("EventDispatcherImpl: started {}", t.getName());
  50                 while (true) {
  51                     AbstractEvent ev;
  52                     try {
  53                         ev = events.take();
  54                     } catch (InterruptedException e) {
  55                         logger.info("The event handler thread was interrupted, shutting down", e);
  56                         return;
  57                     }
  58                     try {
  59                         dispatchEvent(ev);
  60                     } catch (Exception e) {
  61                         logger.error("Exception in dispatching event "+ev.toString(), e);
  62                     }
  63                 }
  64             }
  65         });
  66         logger.debug("event dispatcher is started");
  67     }
  68
  69     void stop() {
  70         // stop accepting new tasks
  71         eventHandler.shutdown();
  72         try {
  73             // Wait a while for existing tasks to terminate
  74             if (!eventHandler.awaitTermination(10, TimeUnit.SECONDS)) {
  75                 eventHandler.shutdownNow();
  76                 // Wait a while for tasks to respond to being cancelled
  77                 if (!eventHandler.awaitTermination(10, TimeUnit.SECONDS))
  78                     logger.error("Dispatcher's event handler did not terminate");
  79             }
  80         } catch (InterruptedException e) {
  81             // (Re-)Cancel if current thread also interrupted
  82             eventHandler.shutdownNow();
  83             // Preserve interrupt status
  84             Thread.currentThread().interrupt();
  85         }
  86         logger.debug("event dispatcher is stopped");
  87     }
  88
  89     private void dispatchEvent(AbstractEvent ev) {
  90         AbstractHandler handler = handlers[ev.getHandlerType().ordinal()];
  91         if (handler == null) {
  92             logger.warn("event dispatcher found no handler for {}", ev);
  93             return;
  94         }
  95
  96         handler.processEvent(ev);
  97     }
  98
  99     public void eventHandlerAdded(final ServiceReference ref, AbstractHandler handler){
 100         Long pid = (Long) ref.getProperty(org.osgi.framework.Constants.SERVICE_ID);
 101         Object handlerTypeObject = ref.getProperty(Constants.EVENT_HANDLER_TYPE_PROPERTY);
 102         if (!(handlerTypeObject instanceof AbstractEvent.HandlerType)){
 103             logger.error("Abstract handler reg failed to provide a valid handler type {}", handlerTypeObject);
 104             return;
 105         }
 106         AbstractEvent.HandlerType handlerType = (AbstractEvent.HandlerType) handlerTypeObject;
 107         handlers[handlerType.ordinal()] = handler;
 108         logger.debug("Event handler for type {} registered for {}, pid {}",
 109                      handlerType, handler.getClass().getName(), pid);
 110     }
 111
 112     public void eventHandlerRemoved(final ServiceReference ref){
 113         Long pid = (Long) ref.getProperty(org.osgi.framework.Constants.SERVICE_ID);
 114         Object handlerTypeObject = ref.getProperty(Constants.EVENT_HANDLER_TYPE_PROPERTY);
 115         if (!(handlerTypeObject instanceof AbstractEvent.HandlerType)){
 116             logger.error("Abstract handler unreg failed to provide a valid handler type " + handlerTypeObject);
 117             return;
 118         }
 119         AbstractEvent.HandlerType handlerType = (AbstractEvent.HandlerType) handlerTypeObject;
 120         handlers[handlerType.ordinal()] = null;
 121         logger.debug("Event handler for type {} unregistered pid {}", handlerType, pid);
 122     }
 123
 124     /**
 125      * Enqueue the event.
 126      *
 127      * @param event the {@link org.opendaylight.ovsdb.openstack.netvirt.AbstractEvent} event to be handled.
 128      */
 129     @Override
 130     public void enqueueEvent(AbstractEvent event) {
 131         if (event == null) {
 132             logger.warn("enqueueEvent: event is null");
 133             return;
 134         }
 135
 136         try {
 137             events.put(event);
 138         } catch (InterruptedException e) {
 139             logger.error("Thread was interrupted while trying to enqueue event ", e);
 140         }
 141     }
 142
 143     @Override
 144     public void setDependencies(BundleContext bundleContext, ServiceReference serviceReference) {}
 145
 146     @Override
 147     public void setDependencies(Object impl) {}
 148 }