opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/jmx/mbeans/shard/OnDemandShardStateCache.java

   1 /*
   2  * Copyright (c) 2017 Inocybe Technologies 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.controller.cluster.datastore.jmx.mbeans.shard;
   9
  10 import akka.actor.ActorRef;
  11 import akka.pattern.Patterns;
  12 import akka.util.Timeout;
  13 import com.google.common.base.Preconditions;
  14 import com.google.common.base.Stopwatch;
  15 import com.google.common.cache.Cache;
  16 import com.google.common.cache.CacheBuilder;
  17 import java.util.concurrent.TimeUnit;
  18 import org.opendaylight.controller.cluster.datastore.messages.OnDemandShardState;
  19 import org.opendaylight.controller.cluster.raft.client.messages.GetOnDemandRaftState;
  20 import scala.concurrent.Await;
  21
  22 /**
  23  * Maintains a short-lived shared cache of OnDemandShardState.
  24  *
  25  * @author Thomas Pantelis
  26  */
  27 class OnDemandShardStateCache {
  28     private static final Cache<String, OnDemandShardState> ONDEMAND_SHARD_STATE_CACHE =
  29             CacheBuilder.newBuilder().expireAfterWrite(2, TimeUnit.SECONDS).build();
  30
  31     private final ActorRef shardActor;
  32     private final String shardName;
  33     private volatile String stateRetrievalTime;
  34
  35     OnDemandShardStateCache(final String shardName, final ActorRef shardActor) {
  36         this.shardName = Preconditions.checkNotNull(shardName);
  37         this.shardActor = shardActor;
  38     }
  39
  40     OnDemandShardState get() throws Exception {
  41         if (shardActor == null) {
  42             return OnDemandShardState.newBuilder().build();
  43         }
  44
  45         return ONDEMAND_SHARD_STATE_CACHE.get(shardName, this::retrieveState);
  46     }
  47
  48     String getStatRetrievaelTime() {
  49         return stateRetrievalTime;
  50     }
  51
  52     private OnDemandShardState retrieveState() throws Exception {
  53         stateRetrievalTime = null;
  54         Timeout timeout = new Timeout(10, TimeUnit.SECONDS);
  55         Stopwatch timer = Stopwatch.createStarted();
  56
  57         OnDemandShardState state = (OnDemandShardState) Await.result(Patterns.ask(shardActor,
  58                 GetOnDemandRaftState.INSTANCE, timeout), timeout.duration());
  59
  60         stateRetrievalTime = timer.stop().toString();
  61         return state;
  62     }
  63 }