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.CheckedFuture;
  13 import com.google.common.util.concurrent.FluentFuture;
  14 import com.google.common.util.concurrent.Futures;
  15 import com.google.common.util.concurrent.ListenableFuture;
  16 import java.util.ArrayList;
  17 import java.util.Collection;
  18 import java.util.Map;
  19 import java.util.concurrent.Future;
  20 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
  21 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  22 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  23 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  24 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  25 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  26 import org.opendaylight.mdsal.common.api.CommitInfo;
  27 import org.opendaylight.mdsal.common.api.MappingCheckedFuture;
  28 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  29 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32
  33 /**
  34  * Read-Write Transaction, which is composed of several
  35  * {@link DOMStoreWriteTransaction} transactions. A sub-transaction is selected by
  36  * {@link LogicalDatastoreType} type parameter in:
  37  *
  38  * <p>
  39  * <ul>
  40  * <li>{@link #put(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  41  * <li>{@link #delete(LogicalDatastoreType, YangInstanceIdentifier)}
  42  * <li>{@link #merge(LogicalDatastoreType, YangInstanceIdentifier, NormalizedNode)}
  43  * </ul>
  44  *
  45  * <p>
  46  * {@link #commit()} will result in invocation of
  47  * {@link DOMDataCommitImplementation#submit(org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction,
  48  * Iterable)} invocation with all {@link org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort}
  49  * for underlying transactions.
  50  *
  51  * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as
  52  *            subtransaction.
  53  */
  54 class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction> extends
  55         AbstractDOMForwardedCompositeTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
  56     @SuppressWarnings("rawtypes")
  57     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction,
  58             AbstractDOMForwardedTransactionFactory>
  59             IMPL_UPDATER = AtomicReferenceFieldUpdater
  60             .newUpdater(DOMForwardedWriteTransaction.class, AbstractDOMForwardedTransactionFactory.class, "commitImpl");
  61     @SuppressWarnings("rawtypes")
  62     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, Future> FUTURE_UPDATER
  63             = AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, Future.class, "commitFuture");
  64     private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
  65     private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
  66
  67     /**
  68      * Implementation of real commit. It also acts as an indication that
  69      * the transaction is running -- which we flip atomically using
  70      * {@link #IMPL_UPDATER}.
  71      */
  72     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  73
  74     /**
  75      * Future task of transaction commit. It starts off as null, but is
  76      * set appropriately on {@link #commit()} and {@link #cancel()} via
  77      * {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  78      *
  79      * <p>
  80      * Lazy set is safe for use because it is only referenced to in the
  81      * {@link #cancel()} slow path, where we will busy-wait for it. The
  82      * fast path gets the benefit of a store-store barrier instead of the
  83      * usual store-load barrier.
  84      */
  85     private volatile Future<?> commitFuture;
  86
  87     protected DOMForwardedWriteTransaction(final Object identifier, final Map<LogicalDatastoreType, T> backingTxs,
  88                                            final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  89         super(identifier, backingTxs);
  90         this.commitImpl = Preconditions.checkNotNull(commitImpl, "commitImpl must not be null.");
  91     }
  92
  93     @Override
  94     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
  95                     final NormalizedNode<?, ?> data) {
  96         checkRunning(commitImpl);
  97         getSubtransaction(store).write(path, data);
  98     }
  99
 100     @Override
 101     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
 102         checkRunning(commitImpl);
 103         getSubtransaction(store).delete(path);
 104     }
 105
 106     @Override
 107     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
 108                       final NormalizedNode<?, ?> data) {
 109         checkRunning(commitImpl);
 110         getSubtransaction(store).merge(path, data);
 111     }
 112
 113     @Override
 114     public boolean cancel() {
 115         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 116         if (impl != null) {
 117             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 118             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 119             closeSubtransactions();
 120             return true;
 121         }
 122
 123         // The transaction is in process of being submitted or cancelled. Busy-wait
 124         // for the corresponding future.
 125         Future<?> future;
 126         do {
 127             future = commitFuture;
 128         } while (future == null);
 129
 130         return future.cancel(false);
 131     }
 132
 133     @Override
 134     public CheckedFuture<Void, TransactionCommitFailedException> submit() {
 135         return MappingCheckedFuture.create(doCommit(() -> null),
 136                 TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER);
 137     }
 138
 139     @Override
 140     public FluentFuture<? extends CommitInfo> commit() {
 141         return FluentFuture.from(doCommit(CommitInfo::empty));
 142     }
 143
 144     @SuppressWarnings("checkstyle:IllegalCatch")
 145     private <V> ListenableFuture<V> doCommit(Supplier<V> futureValueSupplier) {
 146         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 147         checkRunning(impl);
 148
 149         final Collection<T> txns = getSubtransactions();
 150         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 151
 152         ListenableFuture<V> ret;
 153         try {
 154             for (DOMStoreWriteTransaction txn : txns) {
 155                 cohorts.add(txn.ready());
 156             }
 157
 158             ret = impl.commit(this, cohorts, futureValueSupplier);
 159         } catch (RuntimeException e) {
 160             ret = FluentFuture.from(Futures.immediateFailedFuture(
 161                     TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e)));
 162         }
 163         FUTURE_UPDATER.lazySet(this, ret);
 164         return ret;
 165     }
 166
 167     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 168         Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 169     }
 170 }