openflowplugin/src/main/java/org/opendaylight/openflowplugin/openflow/md/queue/QueueKeeperHarvester.java

   1 /**
   2  * Copyright (c) 2013 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.openflowplugin.openflow.md.queue;
   9
  10 import java.util.Collection;
  11
  12 import org.opendaylight.openflowplugin.api.openflow.md.queue.Enqueuer;
  13 import org.opendaylight.openflowplugin.api.openflow.md.queue.HarvesterHandle;
  14 import org.opendaylight.openflowplugin.api.openflow.md.queue.QueueItem;
  15 import org.opendaylight.openflowplugin.api.openflow.md.queue.QueueKeeper;
  16 import org.slf4j.Logger;
  17 import org.slf4j.LoggerFactory;
  18
  19 /**
  20  * @param <IN>
  21  *
  22  */
  23 public class QueueKeeperHarvester<IN> implements Runnable, HarvesterHandle {
  24     private static Logger LOG = LoggerFactory.getLogger(QueueKeeperHarvester.class);
  25
  26     private final Collection<QueueKeeper<IN>> messageSources;
  27     private final Enqueuer<QueueItem<IN>> enqueuer;
  28     private final Object harvestLock = new Object();
  29     private volatile boolean finishing = false;
  30     private volatile boolean wakeMe = false;
  31
  32     /**
  33      * @param enqueuer
  34      * @param messageSources
  35      */
  36     public QueueKeeperHarvester(final Enqueuer<QueueItem<IN>> enqueuer,
  37             final Collection<QueueKeeper<IN>> messageSources) {
  38         this.enqueuer = enqueuer;
  39         this.messageSources = messageSources;
  40     }
  41
  42     @Override
  43     public void run() {
  44         while (!finishing) {
  45             boolean starving = true;
  46             for (QueueKeeper<IN> source : messageSources) {
  47                 QueueItem<IN> qItem = source.poll();
  48                 if (qItem != null) {
  49                     starving = false;
  50                     enqueuer.enqueueQueueItem(qItem);
  51                 }
  52             }
  53
  54             if (starving) {
  55                 LOG.trace("messageHarvester is about to make a starve sleep");
  56                 synchronized (harvestLock) {
  57                     wakeMe = true;
  58                     try {
  59                         this.harvestLock.wait();
  60                         LOG.trace("messageHarvester is waking up from a starve sleep");
  61                     } catch (InterruptedException e) {
  62                         LOG.warn("message harvester has been interrupted during starve sleep", e);
  63                     } finally {
  64                         wakeMe = false;
  65                     }
  66                 }
  67             }
  68         }
  69     }
  70
  71     /**
  72      * finish harvester
  73      */
  74     public void shutdown() {
  75         this.finishing = true;
  76         ping();
  77     }
  78
  79     @Override
  80     public void ping() {
  81         if (wakeMe) {
  82             synchronized (harvestLock) {
  83                 // Might've raced while waiting for lock, so need to recheck
  84                 if (wakeMe) {
  85                     LOG.debug("pinging message harvester in starve status");
  86                     harvestLock.notify();
  87                 }
  88             }
  89         }
  90     }
  91 }