dom/mdsal-dom-broker/src/main/java/org/opendaylight/mdsal/dom/broker/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.broker;
   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.UncancellableListenableFuture;
  23 import org.opendaylight.mdsal.dom.spi.store.DOMStoreWriteTransaction;
  24 import org.opendaylight.yangtools.util.concurrent.FluentFutures;
  25 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  26 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29
  30 /**
  31  * Read-Write Transaction, which is composed of several {@link DOMStoreWriteTransaction} transactions. A sub-transaction
  32  * is selected by {@link LogicalDatastoreType} type parameter in:
  33  * <ul>
  34  * <li>{@link #put(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  35  * <li>{@link #delete(LogicalDatastoreType, YangInstanceIdentifier)}
  36  * <li>{@link #merge(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  37  * </ul>
  38  *
  39  * <p>
  40  * {@link #submit()} will result in invocation of
  41  * {@link DOMDataCommitImplementation#submit(org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction, Iterable)}
  42  * invocation with all {@link org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort} for underlying
  43  * transactions.
  44  *
  45  * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as subtransaction.
  46  */
  47 class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction>
  48         extends AbstractDOMForwardedTransaction<T> implements DOMDataTreeWriteTransaction {
  49     @SuppressWarnings("rawtypes")
  50     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction,
  51         AbstractDOMForwardedTransactionFactory> IMPL_UPDATER = AtomicReferenceFieldUpdater.newUpdater(
  52                 DOMForwardedWriteTransaction.class, AbstractDOMForwardedTransactionFactory.class, "commitImpl");
  53     @SuppressWarnings("rawtypes")
  54     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, FluentFuture> FUTURE_UPDATER =
  55             AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, FluentFuture.class,
  56                 "commitFuture");
  57     private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
  58
  59     private final @NonNull SettableFuture<@NonNull CommitInfo> settableCompletion = SettableFuture.create();
  60     private final @NonNull FluentFuture<? extends @NonNull CommitInfo> completionFuture = FluentFuture.from(
  61         new UncancellableListenableFuture<>(settableCompletion));
  62
  63     /*
  64      * Implementation of real commit. It also acts as an indication that the transaction is running -- which we flip
  65      * atomically using {@link #IMPL_UPDATER}.
  66      */
  67     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  68
  69     /*
  70      * Future task of transaction commit. It starts off as null, but is set appropriately on {@link #submit()} and
  71      * {@link #cancel()} via {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  72      *
  73      * Lazy set is safe for use because it is only referenced to in the {@link #cancel()} slow path, where we will
  74      * busy-wait for it. The fast path gets the benefit of a store-store barrier instead of the usual store-load
  75      * barrier.
  76      */
  77     private volatile FluentFuture<?> commitFuture;
  78
  79     protected DOMForwardedWriteTransaction(final Object identifier,
  80             final Function<LogicalDatastoreType, T> backingTxFactory,
  81             final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  82         super(identifier, backingTxFactory);
  83         this.commitImpl = requireNonNull(commitImpl, "commitImpl must not be null.");
  84     }
  85
  86     @Override
  87     public final void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
  88             final NormalizedNode data) {
  89         checkRunning(commitImpl);
  90         getSubtransaction(store).write(path, data);
  91     }
  92
  93     @Override
  94     public final void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  95         checkRunning(commitImpl);
  96         getSubtransaction(store).delete(path);
  97     }
  98
  99     @Override
 100     public final void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
 101             final NormalizedNode data) {
 102         checkRunning(commitImpl);
 103         getSubtransaction(store).merge(path, data);
 104     }
 105
 106     @Override
 107     public final boolean cancel() {
 108         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 109         if (impl != null) {
 110             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 111             FUTURE_UPDATER.lazySet(this, FluentFutures.immediateCancelledFluentFuture());
 112             closeSubtransactions();
 113             return true;
 114         }
 115
 116         // The transaction is in process of being submitted or cancelled. Busy-wait for the corresponding future.
 117         FluentFuture<?> future;
 118         do {
 119             future = commitFuture;
 120         } while (future == null);
 121
 122         return future.isCancelled();
 123     }
 124
 125     @Override
 126     @SuppressWarnings("checkstyle:IllegalCatch")
 127     public final FluentFuture<? extends CommitInfo> commit() {
 128         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 129         checkRunning(impl);
 130
 131         FluentFuture<? extends CommitInfo> ret;
 132         final var tx = getSubtransaction();
 133         if (tx == null) {
 134             ret = CommitInfo.emptyFluentFuture();
 135         } else {
 136             try {
 137                 ret = impl.commit(this, tx.ready());
 138             } catch (RuntimeException e) {
 139                 ret = immediateFailedFluentFuture(TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e));
 140             }
 141         }
 142
 143         settableCompletion.setFuture(ret);
 144         FUTURE_UPDATER.lazySet(this, ret);
 145         return completionFuture;
 146     }
 147
 148     @Override
 149     public final FluentFuture<?> completionFuture() {
 150         return completionFuture;
 151     }
 152
 153     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 154         checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 155     }
 156 }