dom/mdsal-dom-spi/src/main/java/org/opendaylight/mdsal/dom/spi/DOMForwardedWriteTransaction.java

   1 /*
   2  * Copyright (c) 2014 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 package org.opendaylight.mdsal.dom.spi;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12 import static org.opendaylight.yangtools.util.concurrent.FluentFutures.immediateFailedFluentFuture;
  13
  14 import com.google.common.util.concurrent.FluentFuture;
  15 import com.google.common.util.concurrent.SettableFuture;
  16 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
  17 import java.util.function.Function;
  18 import org.eclipse.jdt.annotation.NonNull;
  19 import org.opendaylight.mdsal.common.api.CommitInfo;
  20 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  21 import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction;
  22 import org.opendaylight.mdsal.dom.spi.store.DOMStoreWriteTransaction;
  23 import org.opendaylight.yangtools.util.concurrent.FluentFutures;
  24 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  25 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28
  29 /**
  30  * Read-Write Transaction, which is composed of several {@link DOMStoreWriteTransaction} transactions. A sub-transaction
  31  * is selected by {@link LogicalDatastoreType} type parameter in:
  32  * <ul>
  33  * <li>{@link #put(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  34  * <li>{@link #delete(LogicalDatastoreType, YangInstanceIdentifier)}
  35  * <li>{@link #merge(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  36  * </ul>
  37  *
  38  * <p>
  39  * {@link #submit()} will result in invocation of
  40  * {@link DOMDataCommitImplementation#submit(org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction, Iterable)}
  41  * invocation with all {@link org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort} for underlying
  42  * transactions.
  43  *
  44  * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as subtransaction.
  45  */
  46 class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction>
  47         extends AbstractDOMForwardedTransaction<T> implements DOMDataTreeWriteTransaction {
  48     @SuppressWarnings("rawtypes")
  49     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction,
  50         AbstractDOMForwardedTransactionFactory> IMPL_UPDATER = AtomicReferenceFieldUpdater.newUpdater(
  51                 DOMForwardedWriteTransaction.class, AbstractDOMForwardedTransactionFactory.class, "commitImpl");
  52     @SuppressWarnings("rawtypes")
  53     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, FluentFuture> FUTURE_UPDATER =
  54             AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, FluentFuture.class,
  55                 "commitFuture");
  56     private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
  57
  58     private final @NonNull SettableFuture<@NonNull CommitInfo> settableCompletion = SettableFuture.create();
  59     private final @NonNull FluentFuture<? extends @NonNull CommitInfo> completionFuture = FluentFuture.from(
  60         new UncancellableListenableFuture<>(settableCompletion));
  61
  62     /*
  63      * Implementation of real commit. It also acts as an indication that the transaction is running -- which we flip
  64      * atomically using {@link #IMPL_UPDATER}.
  65      */
  66     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  67
  68     /*
  69      * Future task of transaction commit. It starts off as null, but is set appropriately on {@link #submit()} and
  70      * {@link #cancel()} via {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  71      *
  72      * Lazy set is safe for use because it is only referenced to in the {@link #cancel()} slow path, where we will
  73      * busy-wait for it. The fast path gets the benefit of a store-store barrier instead of the usual store-load
  74      * barrier.
  75      */
  76     private volatile FluentFuture<?> commitFuture;
  77
  78     protected DOMForwardedWriteTransaction(final Object identifier,
  79             final Function<LogicalDatastoreType, T> backingTxFactory,
  80             final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  81         super(identifier, backingTxFactory);
  82         this.commitImpl = requireNonNull(commitImpl, "commitImpl must not be null.");
  83     }
  84
  85     @Override
  86     public final void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
  87             final NormalizedNode data) {
  88         checkRunning(commitImpl);
  89         getSubtransaction(store).write(path, data);
  90     }
  91
  92     @Override
  93     public final void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  94         checkRunning(commitImpl);
  95         getSubtransaction(store).delete(path);
  96     }
  97
  98     @Override
  99     public final void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
 100             final NormalizedNode data) {
 101         checkRunning(commitImpl);
 102         getSubtransaction(store).merge(path, data);
 103     }
 104
 105     @Override
 106     public final boolean cancel() {
 107         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 108         if (impl != null) {
 109             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 110             FUTURE_UPDATER.lazySet(this, FluentFutures.immediateCancelledFluentFuture());
 111             closeSubtransactions();
 112             return true;
 113         }
 114
 115         // The transaction is in process of being submitted or cancelled. Busy-wait for the corresponding future.
 116         FluentFuture<?> future;
 117         do {
 118             future = commitFuture;
 119         } while (future == null);
 120
 121         return future.isCancelled();
 122     }
 123
 124     @Override
 125     @SuppressWarnings("checkstyle:IllegalCatch")
 126     public final FluentFuture<? extends CommitInfo> commit() {
 127         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 128         checkRunning(impl);
 129
 130         FluentFuture<? extends CommitInfo> ret;
 131         final var tx = getSubtransaction();
 132         if (tx == null) {
 133             ret = CommitInfo.emptyFluentFuture();
 134         } else {
 135             try {
 136                 ret = impl.commit(this, tx.ready());
 137             } catch (RuntimeException e) {
 138                 ret = immediateFailedFluentFuture(TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e));
 139             }
 140         }
 141
 142         settableCompletion.setFuture(ret);
 143         FUTURE_UPDATER.lazySet(this, ret);
 144         return completionFuture;
 145     }
 146
 147     @Override
 148     public final FluentFuture<?> completionFuture() {
 149         return completionFuture;
 150     }
 151
 152     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 153         checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 154     }
 155 }