opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/NoOpDOMStoreThreePhaseCommitCohort.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 com.google.common.util.concurrent.Futures;
  12 import com.google.common.util.concurrent.ListenableFuture;
  13 import java.util.Collections;
  14 import java.util.List;
  15 import scala.concurrent.Future;
  16
  17 /**
  18  * A {@link org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort}
  19  * instance given out for empty transactions.
  20  */
  21 final class NoOpDOMStoreThreePhaseCommitCohort extends AbstractThreePhaseCommitCohort {
  22     static final NoOpDOMStoreThreePhaseCommitCohort INSTANCE = new NoOpDOMStoreThreePhaseCommitCohort();
  23
  24     private static final ListenableFuture<Void> IMMEDIATE_VOID_SUCCESS = Futures.immediateFuture(null);
  25     private static final ListenableFuture<Boolean> IMMEDIATE_BOOLEAN_SUCCESS = Futures.immediateFuture(Boolean.TRUE);
  26
  27     private NoOpDOMStoreThreePhaseCommitCohort() {
  28         // Hidden to prevent instantiation
  29     }
  30
  31     @Override
  32     public ListenableFuture<Boolean> canCommit() {
  33         return IMMEDIATE_BOOLEAN_SUCCESS;
  34     }
  35
  36     @Override
  37     public ListenableFuture<Void> preCommit() {
  38         return IMMEDIATE_VOID_SUCCESS;
  39     }
  40
  41     @Override
  42     public ListenableFuture<Void> abort() {
  43         return IMMEDIATE_VOID_SUCCESS;
  44     }
  45
  46     @Override
  47     public ListenableFuture<Void> commit() {
  48         return IMMEDIATE_VOID_SUCCESS;
  49     }
  50
  51     @Override
  52     List<Future<ActorSelection>> getCohortFutures() {
  53         return Collections.emptyList();
  54     }
  55 }