opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/ClientBackedTransaction.java

   1 /*
   2  * Copyright (c) 2016 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.cluster.databroker;
   9
  10 import com.google.common.base.FinalizablePhantomReference;
  11 import com.google.common.base.FinalizableReferenceQueue;
  12 import com.google.common.base.Preconditions;
  13 import java.util.Set;
  14 import java.util.concurrent.ConcurrentHashMap;
  15 import javax.annotation.Nonnull;
  16 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  17 import org.opendaylight.controller.cluster.databroker.actors.dds.AbstractClientHandle;
  18 import org.opendaylight.controller.cluster.databroker.actors.dds.ClientTransaction;
  19 import org.opendaylight.controller.sal.core.spi.data.AbstractDOMStoreTransaction;
  20 import org.slf4j.Logger;
  21 import org.slf4j.LoggerFactory;
  22
  23 /**
  24  * An implementation of {@link DOMStoreTransaction} backed by a {@link ClientTransaction}. It guards against user-level
  25  * leaks by maintaining a phantom reference on the backing transaction, which will ensure that the transaction will
  26  * be aborted, if it is not otherwise closed, just before this object is garbage-collected.
  27  *
  28  * @author Robert Varga
  29  */
  30 abstract class ClientBackedTransaction<T extends AbstractClientHandle<?>> extends
  31         AbstractDOMStoreTransaction<TransactionIdentifier> {
  32     private static final class Finalizer extends FinalizablePhantomReference<ClientBackedTransaction<?>> {
  33         private static final FinalizableReferenceQueue QUEUE = new FinalizableReferenceQueue();
  34         private static final Set<Finalizer> FINALIZERS = ConcurrentHashMap.newKeySet();
  35         private static final Logger LOG = LoggerFactory.getLogger(Finalizer.class);
  36
  37         private final AbstractClientHandle<?> transaction;
  38
  39         private Finalizer(final ClientBackedTransaction<?> referent, final AbstractClientHandle<?> transaction) {
  40             super(referent, QUEUE);
  41             this.transaction = Preconditions.checkNotNull(transaction);
  42         }
  43
  44         static @Nonnull <T extends AbstractClientHandle<?>> T recordTransaction(
  45                 @Nonnull final ClientBackedTransaction<T> referent, @Nonnull final T transaction) {
  46             FINALIZERS.add(new Finalizer(referent, transaction));
  47             return transaction;
  48         }
  49
  50         @Override
  51         public void finalizeReferent() {
  52             FINALIZERS.remove(this);
  53             if (transaction.abort()) {
  54                 LOG.warn("Aborted orphan transaction {}", transaction.getIdentifier());
  55             }
  56         }
  57     }
  58
  59     private final T delegate;
  60
  61     ClientBackedTransaction(final T delegate) {
  62         super(delegate.getIdentifier());
  63         this.delegate = Finalizer.recordTransaction(this, delegate);
  64     }
  65
  66     final T delegate() {
  67         return delegate;
  68     }
  69
  70     @Override
  71     public void close() {
  72         delegate.abort();
  73     }
  74 }