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