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.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.eclipse.jdt.annotation.NonNull;
  22 import org.opendaylight.mdsal.common.api.CommitInfo;
  23 import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
  24 import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction;
  25 import org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort;
  26 import org.opendaylight.mdsal.dom.spi.store.DOMStoreWriteTransaction;
  27 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  28 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 /**
  33  * Read-Write Transaction, which is composed of several {@link DOMStoreWriteTransaction} transactions. A sub-transaction
  34  * is selected by {@link LogicalDatastoreType} type parameter in:
  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 {@link org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort} for underlying
  45  * 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 the transaction is running -- which we flip
  63      * atomically using {@link #IMPL_UPDATER}.
  64      */
  65     private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
  66
  67     /*
  68      * Future task of transaction commit. It starts off as null, but is set appropriately on {@link #submit()} and
  69      * {@link #cancel()} via {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
  70      *
  71      * Lazy set is safe for use because it is only referenced to in the {@link #cancel()} slow path, where we will
  72      * busy-wait for it. The fast path gets the benefit of a store-store barrier instead of the usual store-load
  73      * barrier.
  74      */
  75     private volatile Future<?> commitFuture;
  76
  77     protected DOMForwardedWriteTransaction(final Object identifier, final Map<LogicalDatastoreType, T> backingTxs,
  78             final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  79         super(identifier, backingTxs);
  80         this.commitImpl = requireNonNull(commitImpl, "commitImpl must not be null.");
  81     }
  82
  83     @Override
  84     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode data) {
  85         checkRunning(commitImpl);
  86         getSubtransaction(store).write(path, data);
  87     }
  88
  89     @Override
  90     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  91         checkRunning(commitImpl);
  92         getSubtransaction(store).delete(path);
  93     }
  94
  95     @Override
  96     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode data) {
  97         checkRunning(commitImpl);
  98         getSubtransaction(store).merge(path, data);
  99     }
 100
 101     @Override
 102     public boolean cancel() {
 103         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 104         if (impl != null) {
 105             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 106             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 107             closeSubtransactions();
 108             return true;
 109         }
 110
 111         // The transaction is in process of being submitted or cancelled. Busy-wait
 112         // for the corresponding future.
 113         Future<?> future;
 114         do {
 115             future = commitFuture;
 116         } while (future == null);
 117
 118         return future.cancel(false);
 119     }
 120
 121     @Override
 122     @SuppressWarnings("checkstyle:IllegalCatch")
 123     public @NonNull FluentFuture<? extends @NonNull CommitInfo> commit() {
 124         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 125         checkRunning(impl);
 126
 127         final Collection<T> txns = getSubtransactions();
 128         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 129
 130         FluentFuture<? extends CommitInfo> ret;
 131         try {
 132             for (final DOMStoreWriteTransaction txn : txns) {
 133                 cohorts.add(txn.ready());
 134             }
 135
 136             ret = impl.commit(this, cohorts);
 137         } catch (RuntimeException e) {
 138             ret = immediateFailedFluentFuture(TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER.apply(e));
 139         }
 140         FUTURE_UPDATER.lazySet(this, ret);
 141         return ret;
 142     }
 143
 144     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 145         checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 146     }
 147 }