opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/selectionstrategy/EntityOwnerSelectionStrategyWrapper.java

   1 /*
   2  * Copyright (c) 2015 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
   9 package org.opendaylight.controller.cluster.datastore.entityownership.selectionstrategy;
  10
  11 import akka.actor.ActorRef;
  12 import akka.actor.Cancellable;
  13 import akka.actor.Scheduler;
  14 import com.google.common.base.Preconditions;
  15 import java.util.Collection;
  16 import java.util.concurrent.TimeUnit;
  17 import org.opendaylight.controller.cluster.datastore.entityownership.messages.SelectOwner;
  18 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  19 import scala.concurrent.ExecutionContextExecutor;
  20 import scala.concurrent.duration.FiniteDuration;
  21
  22 /**
  23  * The EntityOwnerSelectionStrategyWrapper is an EntityOwnerSelectionStrategy decorator that adds the ability to
  24  * schedule an owner selection job.
  25  */
  26 public class EntityOwnerSelectionStrategyWrapper implements EntityOwnerSelectionStrategy {
  27     private final Scheduler scheduler;
  28     private final ActorRef shard;
  29     private final ExecutionContextExecutor dispatcher;
  30     private final EntityOwnerSelectionStrategy strategy;
  31
  32     private Cancellable lastScheduledTask;
  33
  34     public EntityOwnerSelectionStrategyWrapper(Scheduler scheduler,
  35                                                 ActorRef shard,
  36                                                 ExecutionContextExecutor dispatcher,
  37                                                 EntityOwnerSelectionStrategy strategy) {
  38         this.scheduler = Preconditions.checkNotNull(scheduler);
  39         this.shard = Preconditions.checkNotNull(shard);
  40         this.dispatcher = Preconditions.checkNotNull(dispatcher);
  41         this.strategy = Preconditions.checkNotNull(strategy);
  42     }
  43
  44     /**
  45      * Schedule a new owner selection job. Cancelling any outstanding job if it has not been cancelled.
  46      *
  47      * @param entityPath
  48      * @param allCandidates
  49      */
  50     public void scheduleOwnerSelection(YangInstanceIdentifier entityPath, Collection<String> allCandidates){
  51         if(lastScheduledTask != null && !lastScheduledTask.isCancelled()){
  52             lastScheduledTask.cancel();
  53         }
  54         lastScheduledTask = scheduler.scheduleOnce(
  55                 FiniteDuration.apply(strategy.selectionDelayInMillis(), TimeUnit.MILLISECONDS)
  56                 , shard, new SelectOwner(entityPath, allCandidates, strategy)
  57                 , dispatcher, shard);
  58     }
  59
  60     @Override
  61     public long selectionDelayInMillis(){
  62         return strategy.selectionDelayInMillis();
  63     }
  64
  65     @Override
  66     public String newOwner(Collection<String> viableCandidates){
  67         return strategy.newOwner(viableCandidates);
  68     }
  69 }