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      * @param harvestLock
  36      */
  37     public QueueKeeperHarvester(final Enqueuer<QueueItem<IN>> enqueuer,
  38             final Collection<QueueKeeper<IN>> messageSources) {
  39         this.enqueuer = enqueuer;
  40         this.messageSources = messageSources;
  41     }
  42
  43     @Override
  44     public void run() {
  45         while (!finishing) {
  46             boolean starving = true;
  47             for (QueueKeeper<IN> source : messageSources) {
  48                 QueueItem<IN> qItem = source.poll();
  49                 if (qItem != null) {
  50                     starving = false;
  51                     enqueuer.enqueueQueueItem(qItem);
  52                 }
  53             }
  54
  55             if (starving) {
  56                 LOG.trace("messageHarvester is about to make a starve sleep");
  57                 synchronized (harvestLock) {
  58                     wakeMe = true;
  59                     try {
  60                         this.harvestLock.wait();
  61                         LOG.trace("messageHarvester is waking up from a starve sleep");
  62                     } catch (InterruptedException e) {
  63                         LOG.warn("message harvester has been interrupted during starve sleep", e);
  64                     } finally {
  65                         wakeMe = false;
  66                     }
  67                 }
  68             }
  69         }
  70     }
  71
  72     /**
  73      * finish harvester
  74      */
  75     public void shutdown() {
  76         this.finishing = true;
  77         ping();
  78     }
  79
  80     @Override
  81     public void ping() {
  82         if (wakeMe) {
  83             synchronized (harvestLock) {
  84                 // Might've raced while waiting for lock, so need to recheck
  85                 if (wakeMe) {
  86                     LOG.debug("pinging message harvester in starve status");
  87                     harvestLock.notify();
  88                 }
  89             }
  90         }
  91     }
  92 }