opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/DOMBrokerWriteOnlyTransaction.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.databroker;
  10
  11 import com.google.common.base.Preconditions;
  12 import com.google.common.util.concurrent.CheckedFuture;
  13 import com.google.common.util.concurrent.Futures;
  14 import com.google.common.util.concurrent.ListenableFuture;
  15 import java.util.ArrayList;
  16 import java.util.Collection;
  17 import java.util.Map;
  18 import java.util.concurrent.Future;
  19 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
  20 import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
  21 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  22 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  23 import org.opendaylight.controller.md.sal.common.impl.service.AbstractDataTransaction;
  24 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  25 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  26 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  27 import org.opendaylight.yangtools.yang.common.RpcResult;
  28 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  29 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32
  33 public class DOMBrokerWriteOnlyTransaction<T extends DOMStoreWriteTransaction>
  34         extends AbstractDOMBrokerTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
  35
  36     private static final AtomicReferenceFieldUpdater<DOMBrokerWriteOnlyTransaction, AbstractDOMTransactionFactory> IMPL_UPDATER =
  37             AtomicReferenceFieldUpdater.newUpdater(DOMBrokerWriteOnlyTransaction.class, AbstractDOMTransactionFactory.class, "commitImpl");
  38     @SuppressWarnings("rawtypes")
  39     private static final AtomicReferenceFieldUpdater<DOMBrokerWriteOnlyTransaction, Future> FUTURE_UPDATER =
  40             AtomicReferenceFieldUpdater.newUpdater(DOMBrokerWriteOnlyTransaction.class, Future.class, "commitFuture");
  41     private static final Logger LOG = LoggerFactory.getLogger(DOMBrokerWriteOnlyTransaction.class);
  42     private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
  43
  44     /**
  45      * Implementation of real commit. It also acts as an indication that
  46      * the transaction is running -- which we flip atomically using
  47      * {@link #IMPL_UPDATER}.
  48      */
  49     private volatile AbstractDOMTransactionFactory<?> commitImpl;
  50
  51     /**
  52      * Future task of transaction commit. It starts off as null, but is
  53      * set appropriately on {@link #submit()} and {@link #cancel()} via
  54      * {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  55      *
  56      * Lazy set is safe for use because it is only referenced to in the
  57      * {@link #cancel()} slow path, where we will busy-wait for it. The
  58      * fast path gets the benefit of a store-store barrier instead of the
  59      * usual store-load barrier.
  60      */
  61     private volatile Future<?> commitFuture;
  62
  63     protected DOMBrokerWriteOnlyTransaction(final Object identifier,
  64                                             Map storeTxFactories, final AbstractDOMTransactionFactory<?> commitImpl) {
  65         super(identifier, storeTxFactories);
  66         this.commitImpl = Preconditions.checkNotNull(commitImpl, "commitImpl must not be null.");
  67     }
  68
  69     @Override
  70     protected T createTransaction(LogicalDatastoreType key) {
  71         // FIXME : Casting shouldn't be necessary here
  72         return (T) getTxFactory(key).newWriteOnlyTransaction();
  73     }
  74
  75     @Override
  76     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
  77         checkRunning(commitImpl);
  78         getSubtransaction(store).write(path, data);
  79     }
  80
  81     @Override
  82     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  83         checkRunning(commitImpl);
  84         getSubtransaction(store).delete(path);
  85     }
  86
  87     @Override
  88     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
  89         checkRunning(commitImpl);
  90         getSubtransaction(store).merge(path, data);
  91     }
  92
  93     @Override
  94     public boolean cancel() {
  95         final AbstractDOMTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
  96         if (impl != null) {
  97             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
  98             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
  99             closeSubtransactions();
 100             return true;
 101         }
 102
 103         // The transaction is in process of being submitted or cancelled. Busy-wait
 104         // for the corresponding future.
 105         Future<?> future;
 106         do {
 107             future = commitFuture;
 108         } while (future == null);
 109
 110         return future.cancel(false);
 111     }
 112
 113     @Deprecated
 114     @Override
 115     public ListenableFuture<RpcResult<TransactionStatus>> commit() {
 116         return AbstractDataTransaction.convertToLegacyCommitFuture(submit());
 117     }
 118
 119     @Override
 120     public CheckedFuture<Void, TransactionCommitFailedException> submit() {
 121         final AbstractDOMTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 122         checkRunning(impl);
 123
 124         final Collection<T> txns = getSubtransactions();
 125         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 126
 127         // FIXME: deal with errors thrown by backed (ready and submit can fail in theory)
 128         for (DOMStoreWriteTransaction txn : txns) {
 129             cohorts.add(txn.ready());
 130         }
 131
 132         final CheckedFuture<Void, TransactionCommitFailedException> ret = impl.submit(this, cohorts);
 133         FUTURE_UPDATER.lazySet(this, ret);
 134         return ret;
 135     }
 136
 137     private void checkRunning(final AbstractDOMTransactionFactory<?> impl) {
 138         Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 139     }
 140
 141 }