opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/broker/impl/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.controller.md.sal.dom.broker.impl;
   9
  10 import com.google.common.base.Preconditions;
  11 import com.google.common.base.Supplier;
  12 import com.google.common.util.concurrent.FluentFuture;
  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.data.LogicalDatastoreType;
  21 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  22 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  23 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  24 import org.opendaylight.mdsal.common.api.CommitInfo;
  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  * <p>
  36  * <ul>
  37  * <li>{@link #put(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  38  * <li>{@link #delete(LogicalDatastoreType, YangInstanceIdentifier)}
  39  * <li>{@link #merge(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  40  * </ul>
  41  *
  42  * <p>
  43  * {@link #commit()} will result in invocation of
  44  * {@link DOMDataCommitImplementation#submit(org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction,
  45  * Iterable)} invocation with all {@link org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort}
  46  * for underlying transactions.
  47  *
  48  * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as
  49  *            subtransaction.
  50  */
  51 class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction> extends
  52         AbstractDOMForwardedCompositeTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
  53     @SuppressWarnings("rawtypes")
  54     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction,
  55             AbstractDOMForwardedTransactionFactory>
  56             IMPL_UPDATER = AtomicReferenceFieldUpdater
  57             .newUpdater(DOMForwardedWriteTransaction.class, AbstractDOMForwardedTransactionFactory.class, "commitImpl");
  58     @SuppressWarnings("rawtypes")
  59     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, Future> FUTURE_UPDATER
  60             = AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, Future.class, "commitFuture");
  61     private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
  62     private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
  63
  64     /**
  65      * Implementation of real commit. It also acts as an indication that
  66      * the transaction is running -- which we flip atomically using
  67      * {@link #IMPL_UPDATER}.
  68      */
  69     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  70
  71     /**
  72      * Future task of transaction commit. It starts off as null, but is
  73      * set appropriately on {@link #commit()} and {@link #cancel()} via
  74      * {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  75      *
  76      * <p>
  77      * Lazy set is safe for use because it is only referenced to in the
  78      * {@link #cancel()} slow path, where we will busy-wait for it. The
  79      * fast path gets the benefit of a store-store barrier instead of the
  80      * usual store-load barrier.
  81      */
  82     private volatile Future<?> commitFuture;
  83
  84     protected DOMForwardedWriteTransaction(final Object identifier, final Map<LogicalDatastoreType, T> backingTxs,
  85                                            final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  86         super(identifier, backingTxs);
  87         this.commitImpl = Preconditions.checkNotNull(commitImpl, "commitImpl must not be null.");
  88     }
  89
  90     @Override
  91     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
  92                     final NormalizedNode<?, ?> data) {
  93         checkRunning(commitImpl);
  94         getSubtransaction(store).write(path, data);
  95     }
  96
  97     @Override
  98     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  99         checkRunning(commitImpl);
 100         getSubtransaction(store).delete(path);
 101     }
 102
 103     @Override
 104     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
 105                       final NormalizedNode<?, ?> data) {
 106         checkRunning(commitImpl);
 107         getSubtransaction(store).merge(path, data);
 108     }
 109
 110     @Override
 111     public boolean cancel() {
 112         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 113         if (impl != null) {
 114             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 115             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 116             closeSubtransactions();
 117             return true;
 118         }
 119
 120         // The transaction is in process of being submitted or cancelled. Busy-wait
 121         // for the corresponding future.
 122         Future<?> future;
 123         do {
 124             future = commitFuture;
 125         } while (future == null);
 126
 127         return future.cancel(false);
 128     }
 129
 130     @Override
 131     public FluentFuture<? extends CommitInfo> commit() {
 132         return FluentFuture.from(doCommit(CommitInfo::empty));
 133     }
 134
 135     @SuppressWarnings("checkstyle:IllegalCatch")
 136     private <V> ListenableFuture<V> doCommit(Supplier<V> futureValueSupplier) {
 137         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 138         checkRunning(impl);
 139
 140         final Collection<T> txns = getSubtransactions();
 141         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 142
 143         ListenableFuture<V> ret;
 144         try {
 145             for (DOMStoreWriteTransaction txn : txns) {
 146                 cohorts.add(txn.ready());
 147             }
 148
 149             ret = impl.commit(this, cohorts, futureValueSupplier);
 150         } catch (RuntimeException e) {
 151             ret = FluentFuture.from(Futures.immediateFailedFuture(
 152                     TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e)));
 153         }
 154         FUTURE_UPDATER.lazySet(this, ret);
 155         return ret;
 156     }
 157
 158     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 159         Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 160     }
 161 }