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