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