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.Futures;
  16 import java.util.concurrent.Future;
  17 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
  18 import java.util.function.Function;
  19 import org.eclipse.jdt.annotation.NonNull;
  20 import org.opendaylight.mdsal.common.api.CommitInfo;
  21 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  22 import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction;
  23 import org.opendaylight.mdsal.dom.spi.store.DOMStoreWriteTransaction;
  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, Future> FUTURE_UPDATER =
  54             AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, Future.class, "commitFuture");
  55     private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
  56     private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
  57
  58     /*
  59      * Implementation of real commit. It also acts as an indication that the transaction is running -- which we flip
  60      * atomically using {@link #IMPL_UPDATER}.
  61      */
  62     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  63
  64     /*
  65      * Future task of transaction commit. It starts off as null, but is set appropriately on {@link #submit()} and
  66      * {@link #cancel()} via {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  67      *
  68      * Lazy set is safe for use because it is only referenced to in the {@link #cancel()} slow path, where we will
  69      * busy-wait for it. The fast path gets the benefit of a store-store barrier instead of the usual store-load
  70      * barrier.
  71      */
  72     private volatile Future<?> commitFuture;
  73
  74     protected DOMForwardedWriteTransaction(final Object identifier,
  75             final Function<LogicalDatastoreType, T> backingTxFactory,
  76             final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  77         super(identifier, backingTxFactory);
  78         this.commitImpl = requireNonNull(commitImpl, "commitImpl must not be null.");
  79     }
  80
  81     @Override
  82     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode data) {
  83         checkRunning(commitImpl);
  84         getSubtransaction(store).write(path, data);
  85     }
  86
  87     @Override
  88     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  89         checkRunning(commitImpl);
  90         getSubtransaction(store).delete(path);
  91     }
  92
  93     @Override
  94     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode data) {
  95         checkRunning(commitImpl);
  96         getSubtransaction(store).merge(path, data);
  97     }
  98
  99     @Override
 100     public boolean cancel() {
 101         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 102         if (impl != null) {
 103             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 104             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 105             closeSubtransactions();
 106             return true;
 107         }
 108
 109         // The transaction is in process of being submitted or cancelled. Busy-wait
 110         // for the corresponding future.
 111         Future<?> future;
 112         do {
 113             future = commitFuture;
 114         } while (future == null);
 115
 116         return future.cancel(false);
 117     }
 118
 119     @Override
 120     @SuppressWarnings("checkstyle:IllegalCatch")
 121     public @NonNull FluentFuture<? extends @NonNull CommitInfo> commit() {
 122         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 123         checkRunning(impl);
 124
 125         FluentFuture<? extends CommitInfo> ret;
 126         final var tx = getSubtransaction();
 127         if (tx == null) {
 128             ret = CommitInfo.emptyFluentFuture();
 129         } else {
 130             try {
 131                 ret = impl.commit(this, tx.ready());
 132             } catch (RuntimeException e) {
 133                 ret = immediateFailedFluentFuture(TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e));
 134             }
 135         }
 136
 137         FUTURE_UPDATER.lazySet(this, ret);
 138         return ret;
 139     }
 140
 141     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 142         checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 143     }
 144 }