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.YangInstanceIdentifier.PathArgument;
  30 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33
  34 public class DOMBrokerWriteOnlyTransaction<T extends DOMStoreWriteTransaction>
  35         extends AbstractDOMBrokerTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
  36
  37     private static final AtomicReferenceFieldUpdater<DOMBrokerWriteOnlyTransaction, AbstractDOMTransactionFactory> IMPL_UPDATER =
  38             AtomicReferenceFieldUpdater.newUpdater(DOMBrokerWriteOnlyTransaction.class, AbstractDOMTransactionFactory.class, "commitImpl");
  39     @SuppressWarnings("rawtypes")
  40     private static final AtomicReferenceFieldUpdater<DOMBrokerWriteOnlyTransaction, Future> FUTURE_UPDATER =
  41             AtomicReferenceFieldUpdater.newUpdater(DOMBrokerWriteOnlyTransaction.class, Future.class, "commitFuture");
  42     private static final Logger LOG = LoggerFactory.getLogger(DOMBrokerWriteOnlyTransaction.class);
  43     private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
  44
  45     /**
  46      * Implementation of real commit. It also acts as an indication that
  47      * the transaction is running -- which we flip atomically using
  48      * {@link #IMPL_UPDATER}.
  49      */
  50     private volatile AbstractDOMTransactionFactory<?> commitImpl;
  51
  52     /**
  53      * Future task of transaction commit. It starts off as null, but is
  54      * set appropriately on {@link #submit()} and {@link #cancel()} via
  55      * {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  56      *
  57      * Lazy set is safe for use because it is only referenced to in the
  58      * {@link #cancel()} slow path, where we will busy-wait for it. The
  59      * fast path gets the benefit of a store-store barrier instead of the
  60      * usual store-load barrier.
  61      */
  62     private volatile Future<?> commitFuture;
  63
  64     protected DOMBrokerWriteOnlyTransaction(final Object identifier,
  65                                             final Map storeTxFactories, final AbstractDOMTransactionFactory<?> commitImpl) {
  66         super(identifier, storeTxFactories);
  67         this.commitImpl = Preconditions.checkNotNull(commitImpl, "commitImpl must not be null.");
  68     }
  69
  70     @Override
  71     protected T createTransaction(final LogicalDatastoreType key) {
  72         // FIXME : Casting shouldn't be necessary here
  73         return (T) getTxFactory(key).newWriteOnlyTransaction();
  74     }
  75
  76     @Override
  77     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
  78         checkRunning(commitImpl);
  79         checkInstanceIdentifierReferencesData(path,data);
  80         getSubtransaction(store).write(path, data);
  81     }
  82
  83     private static void checkInstanceIdentifierReferencesData(final YangInstanceIdentifier path,
  84             final NormalizedNode<?, ?> data) {
  85         final PathArgument lastArg = path.getLastPathArgument();
  86         Preconditions.checkArgument(
  87                 (lastArg == data.getIdentifier()) || (lastArg != null && lastArg.equals(data.getIdentifier())),
  88                 "Instance identifier references %s but data identifier is %s", lastArg, data);
  89     }
  90
  91     @Override
  92     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  93         checkRunning(commitImpl);
  94         getSubtransaction(store).delete(path);
  95     }
  96
  97     @Override
  98     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
  99         checkRunning(commitImpl);
 100         checkInstanceIdentifierReferencesData(path, data);
 101         getSubtransaction(store).merge(path, data);
 102     }
 103
 104     @Override
 105     public boolean cancel() {
 106         final AbstractDOMTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 107         if (impl != null) {
 108             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 109             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 110             closeSubtransactions();
 111             return true;
 112         }
 113
 114         // The transaction is in process of being submitted or cancelled. Busy-wait
 115         // for the corresponding future.
 116         Future<?> future;
 117         do {
 118             future = commitFuture;
 119         } while (future == null);
 120
 121         return future.cancel(false);
 122     }
 123
 124     @Deprecated
 125     @Override
 126     public ListenableFuture<RpcResult<TransactionStatus>> commit() {
 127         return AbstractDataTransaction.convertToLegacyCommitFuture(submit());
 128     }
 129
 130     @Override
 131     public CheckedFuture<Void, TransactionCommitFailedException> submit() {
 132         final AbstractDOMTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 133         checkRunning(impl);
 134
 135         final Collection<T> txns = getSubtransactions();
 136         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 137
 138         // FIXME: deal with errors thrown by backed (ready and submit can fail in theory)
 139         for (final DOMStoreWriteTransaction txn : txns) {
 140             cohorts.add(txn.ready());
 141         }
 142
 143         final CheckedFuture<Void, TransactionCommitFailedException> ret = impl.submit(this, cohorts);
 144         FUTURE_UPDATER.lazySet(this, ret);
 145         return ret;
 146     }
 147
 148     private void checkRunning(final AbstractDOMTransactionFactory<?> impl) {
 149         Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 150     }
 151
 152 }