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