opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/SingleCommitCohortProxy.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications 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.controller.cluster.datastore;
   9
  10 import akka.actor.ActorSelection;
  11 import akka.dispatch.Futures;
  12 import akka.dispatch.OnComplete;
  13 import com.google.common.util.concurrent.FutureCallback;
  14 import com.google.common.util.concurrent.ListenableFuture;
  15 import com.google.common.util.concurrent.SettableFuture;
  16 import java.util.Arrays;
  17 import java.util.List;
  18 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  19 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  20 import org.slf4j.Logger;
  21 import org.slf4j.LoggerFactory;
  22 import scala.concurrent.Future;
  23
  24 /**
  25  * A cohort proxy implementation for a single-shard transaction commit. If the transaction was a direct commit
  26  * to the shard, this implementation elides the CanCommitTransaction and CommitTransaction messages to the
  27  * shard as an optimization. Otherwise the 3-phase commit to the shard is delegated to a
  28  * ThreePhaseCommitCohortProxy instance (this is for backwards compatibility with pre-Lithium versions).
  29  *
  30  * @author Thomas Pantelis
  31  */
  32 class SingleCommitCohortProxy extends AbstractThreePhaseCommitCohort<Object> {
  33     private static final Logger LOG = LoggerFactory.getLogger(SingleCommitCohortProxy.class);
  34
  35     private final ActorContext actorContext;
  36     private final Future<Object> cohortFuture;
  37     private final String transactionId;
  38     private volatile DOMStoreThreePhaseCommitCohort delegateCohort = NoOpDOMStoreThreePhaseCommitCohort.INSTANCE;
  39     private final OperationCallback.Reference operationCallbackRef;
  40
  41     SingleCommitCohortProxy(ActorContext actorContext, Future<Object> cohortFuture, String transactionId,
  42             OperationCallback.Reference operationCallbackRef) {
  43         this.actorContext = actorContext;
  44         this.cohortFuture = cohortFuture;
  45         this.transactionId = transactionId;
  46         this.operationCallbackRef = operationCallbackRef;
  47     }
  48
  49     @Override
  50     public ListenableFuture<Boolean> canCommit() {
  51         LOG.debug("Tx {} canCommit", transactionId);
  52
  53         final SettableFuture<Boolean> returnFuture = SettableFuture.create();
  54
  55         cohortFuture.onComplete(new OnComplete<Object>() {
  56             @Override
  57             public void onComplete(Throwable failure, Object cohortResponse) {
  58                 if(failure != null) {
  59                     operationCallbackRef.get().failure();
  60                     returnFuture.setException(failure);
  61                     return;
  62                 }
  63
  64                 operationCallbackRef.get().success();
  65
  66                 if(cohortResponse instanceof ActorSelection) {
  67                     handlePreLithiumActorCohort((ActorSelection)cohortResponse, returnFuture);
  68                     return;
  69                 }
  70
  71                 LOG.debug("Tx {} successfully completed direct commit", transactionId);
  72
  73                 // The Future was the result of a direct commit to the shard, essentially eliding the
  74                 // front-end 3PC coordination. We don't really care about the specific Future
  75                 // response object, only that it completed successfully. At this point the Tx is complete
  76                 // so return true. The subsequent preCommit and commit phases will be no-ops, ie return
  77                 // immediate success, to complete the 3PC for the front-end.
  78                 returnFuture.set(Boolean.TRUE);
  79             }
  80         }, actorContext.getClientDispatcher());
  81
  82         return returnFuture;
  83     }
  84
  85     @Override
  86     public ListenableFuture<Void> preCommit() {
  87         return delegateCohort.preCommit();
  88     }
  89
  90     @Override
  91     public ListenableFuture<Void> abort() {
  92         return delegateCohort.abort();
  93     }
  94
  95     @Override
  96     public ListenableFuture<Void> commit() {
  97         return delegateCohort.commit();
  98     }
  99
 100     @Override
 101     List<Future<Object>> getCohortFutures() {
 102         return Arrays.asList(cohortFuture);
 103     }
 104
 105     private void handlePreLithiumActorCohort(ActorSelection actorSelection, final SettableFuture<Boolean> returnFuture) {
 106         // Handle backwards compatibility. An ActorSelection response would be returned from a
 107         // pre-Lithium version. In this case delegate to a ThreePhaseCommitCohortProxy.
 108         delegateCohort = new ThreePhaseCommitCohortProxy(actorContext,
 109                 Arrays.asList(Futures.successful(actorSelection)), transactionId);
 110         com.google.common.util.concurrent.Futures.addCallback(delegateCohort.canCommit(), new FutureCallback<Boolean>() {
 111             @Override
 112             public void onSuccess(Boolean canCommit) {
 113                 returnFuture.set(canCommit);
 114             }
 115
 116             @Override
 117             public void onFailure(Throwable t) {
 118                 returnFuture.setException(t);
 119             }
 120         });
 121     }
 122 }