import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.Futures;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
public final class SnapshotBackedReadTransaction<T> extends AbstractDOMStoreTransaction<T>
implements DOMStoreReadTransaction {
private static final Logger LOG = LoggerFactory.getLogger(SnapshotBackedReadTransaction.class);
+
+ @SuppressWarnings("rawtypes")
+ private static final AtomicReferenceFieldUpdater<SnapshotBackedReadTransaction, DataTreeSnapshot> SNAPSHOT_UPDATER =
+ AtomicReferenceFieldUpdater.newUpdater(SnapshotBackedReadTransaction.class, DataTreeSnapshot.class,
+ "stableSnapshot");
+
+ // Guarded by stableSnapshot CAS, hence it does not need to be volatile
+ private TransactionClosePrototype<T> closeImpl;
private volatile DataTreeSnapshot stableSnapshot;
/**
* @param debug Enable transaction debugging
* @param snapshot Snapshot which will be modified.
*/
- SnapshotBackedReadTransaction(final T identifier, final boolean debug, final DataTreeSnapshot snapshot) {
+ SnapshotBackedReadTransaction(final T identifier, final boolean debug, final DataTreeSnapshot snapshot,
+ final TransactionClosePrototype<T> closeImpl) {
super(identifier, debug);
this.stableSnapshot = Preconditions.checkNotNull(snapshot);
+ this.closeImpl = closeImpl;
LOG.debug("ReadOnly Tx: {} allocated with snapshot {}", identifier, snapshot);
}
@Override
public void close() {
+ final DataTreeSnapshot prev = SNAPSHOT_UPDATER.getAndSet(this, null);
+ if (prev == null) {
+ LOG.debug("Store transaction: {} : previously closed", getIdentifier());
+ return;
+ }
+
LOG.debug("Store transaction: {} : Closed", getIdentifier());
- stableSnapshot = null;
+ if (closeImpl != null) {
+ closeImpl.transactionClosed(this);
+ closeImpl = null;
+ }
}
@Override
return Futures.immediateFailedCheckedFuture(e);
}
}
+
+ /**
+ * Prototype implementation of {@link SnapshotBackedReadTransaction#close()}.
+ *
+ * <p>
+ * This class is intended to be implemented by Transaction factories responsible for allocation
+ * of {@link org.opendaylight.mdsal.dom.spi.store.SnapshotBackedReadTransaction} and
+ * providing underlying logic for applying implementation.
+ *
+ * @param <T> identifier type
+ */
+ public interface TransactionClosePrototype<T> {
+ /**
+ * Called when a transaction is closed. This is not invoked at most once for every transaction.
+ *
+ * @param tx Transaction which got closed.
+ */
+ void transactionClosed(SnapshotBackedReadTransaction<T> tx);
+ }
}