dom/mdsal-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.util.concurrent.CheckedFuture;
  12 import com.google.common.util.concurrent.Futures;
  13 import com.google.common.util.concurrent.ListenableFuture;
  14 import java.util.ArrayList;
  15 import java.util.Collection;
  16 import java.util.Map;
  17 import java.util.concurrent.Future;
  18 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
  19 import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
  20 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  21 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  22 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  23 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  24 import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
  25 import org.opendaylight.yangtools.yang.common.RpcResult;
  26 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  27 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30
  31 /**
  32  * Read-Write Transaction, which is composed of several
  33  * {@link DOMStoreWriteTransaction} transactions. A sub-transaction is selected by
  34  * {@link LogicalDatastoreType} type parameter in:
  35  *
  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  * <p>
  42  * {@link #commit()} will result in invocation of
  43  * {@link DOMDataCommitImplementation#submit(org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction, Iterable)}
  44  * invocation with all {@link org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort} for underlying
  45  * transactions.
  46  *
  47  * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as
  48  *            subtransaction.
  49  */
  50 class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction> extends
  51         AbstractDOMForwardedCompositeTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
  52     @SuppressWarnings("rawtypes")
  53     private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, AbstractDOMForwardedTransactionFactory> IMPL_UPDATER =
  54             AtomicReferenceFieldUpdater.newUpdater(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      * Lazy set is safe for use because it is only referenced to in the
  74      * {@link #cancel()} slow path, where we will busy-wait for it. The
  75      * fast path gets the benefit of a store-store barrier instead of the
  76      * usual store-load barrier.
  77      */
  78     private volatile Future<?> commitFuture;
  79
  80     protected DOMForwardedWriteTransaction(final Object identifier,
  81             final Map<LogicalDatastoreType, T> backingTxs, final AbstractDOMForwardedTransactionFactory<?> commitImpl) {
  82         super(identifier, backingTxs);
  83         this.commitImpl = Preconditions.checkNotNull(commitImpl, "commitImpl must not be null.");
  84     }
  85
  86     @Override
  87     public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
  88         checkRunning(commitImpl);
  89         getSubtransaction(store).write(path, data);
  90     }
  91
  92     @Override
  93     public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
  94         checkRunning(commitImpl);
  95         getSubtransaction(store).delete(path);
  96     }
  97
  98     @Override
  99     public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
 100         checkRunning(commitImpl);
 101         getSubtransaction(store).merge(path, data);
 102     }
 103
 104     @Override
 105     public boolean cancel() {
 106         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 107         if (impl != null) {
 108             LOG.trace("Transaction {} cancelled before submit", getIdentifier());
 109             FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
 110             closeSubtransactions();
 111             return true;
 112         }
 113
 114         // The transaction is in process of being submitted or cancelled. Busy-wait
 115         // for the corresponding future.
 116         Future<?> future;
 117         do {
 118             future = commitFuture;
 119         } while (future == null);
 120
 121         return future.cancel(false);
 122     }
 123
 124     @Deprecated
 125     @Override
 126     public ListenableFuture<RpcResult<TransactionStatus>> commit() {
 127         return CommitCompatibility.convertToLegacyCommitFuture(submit());
 128     }
 129
 130     @Override
 131     public CheckedFuture<Void, TransactionCommitFailedException> submit() {
 132         final AbstractDOMForwardedTransactionFactory<?> impl = IMPL_UPDATER.getAndSet(this, null);
 133         checkRunning(impl);
 134
 135         final Collection<T> txns = getSubtransactions();
 136         final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
 137
 138         // FIXME: deal with errors thrown by backed (ready and submit can fail in theory)
 139         for (final DOMStoreWriteTransaction txn : txns) {
 140             cohorts.add(txn.ready());
 141         }
 142
 143         final CheckedFuture<Void, TransactionCommitFailedException> ret = impl.submit(this, cohorts);
 144         FUTURE_UPDATER.lazySet(this, ret);
 145         return ret;
 146     }
 147
 148     private void checkRunning(final AbstractDOMForwardedTransactionFactory<?> impl) {
 149         Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
 150     }
 151 }