+ @SuppressWarnings("rawtypes")
+ private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, AbstractDOMForwardedTransactionFactory> IMPL_UPDATER =
+ AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, AbstractDOMForwardedTransactionFactory.class, "commitImpl");
+ @SuppressWarnings("rawtypes")
+ private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, Future> FUTURE_UPDATER =
+ AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, Future.class, "commitFuture");
+ private static final Logger LOG = LoggerFactory.getLogger(DOMForwardedWriteTransaction.class);
+ private static final Future<?> CANCELLED_FUTURE = Futures.immediateCancelledFuture();
+
+ /**
+ * Implementation of real commit. It also acts as an indication that
+ * the transaction is running -- which we flip atomically using
+ * {@link #IMPL_UPDATER}.
+ */
+ private volatile AbstractDOMForwardedTransactionFactory<?> commitImpl;
+
+ /**
+ * Future task of transaction commit. It starts off as null, but is
+ * set appropriately on {@link #submit()} and {@link #cancel()} via
+ * {@link AtomicReferenceFieldUpdater#lazySet(Object, Object)}.
+ *
+ * Lazy set is safe for use because it is only referenced to in the
+ * {@link #cancel()} slow path, where we will busy-wait for it. The
+ * fast path gets the benefit of a store-store barrier instead of the
+ * usual store-load barrier.
+ */
+ private volatile Future<?> commitFuture;