+ * This behaviour is different from the default AsyncDataBroker, where a + * transaction is always created from the current global state, not taking into + * account any transactions previously committed by the calling thread. Due to + * the asynchronous nature of transaction submission this can lead to surprising + * results. If a thread executes the following sequence sufficiently quickly: + * + *
+ * AsyncWriteTransaction t1 = broker.newWriteOnlyTransaction(); + * t1.put(id, data); + * t1.submit(); + * + *
+ * AsyncReadTransaction t2 = broker.newReadOnlyTransaction(); + * Optional<?> maybeData = t2.read(id).get(); + * + *
+ * it may happen, that it sees maybeData.isPresent() == false, simply because + * t1 has not completed the processes of being applied and t2 is actually + * allocated from the previous state. This is obviously bad for users who create + * incremental state in the datastore and actually read what they write in + * subsequent transactions. + * + *
+ * Using a TransactionChain instead of a broker solves this particular problem, + * and leads to expected behavior: t2 will always see the data written in t1 + * present. */ -public interface TransactionChain
*/, D> extends AutoCloseable { +@Deprecated +public interface TransactionChain
, D> extends AutoCloseable, AsyncDataTransactionFactory
+ * The previous write transaction has to be either SUBMITTED
+ * ({@link AsyncWriteTransaction#submit submit} was invoked) or CANCELLED
+ * ({@link #close close} was invoked).
+ *
+ *
+ * The returned read-only transaction presents an isolated view of the data if the previous
+ * write transaction was successful - in other words, this read-only transaction will see the
+ * state changes made by the previous write transaction in the chain. However, state which
+ * was introduced by other transactions outside this transaction chain after creation of
+ * the previous transaction is not visible.
*
* @return New transaction in the chain.
- * @throws IllegalStateException if the previous transaction was not COMMITTED or CANCELLED.
- * @throws TransactionChainClosedException if the chain has been closed.
+ * @throws IllegalStateException
+ * if the previous transaction was not SUBMITTED or CANCELLED.
+ * @throws TransactionChainClosedException
+ * if the chain has been closed.
*/
- DataModification
+ * The previous write transaction has to be either SUBMITTED
+ * ({@link AsyncWriteTransaction#submit submit} was invoked) or CANCELLED
+ * ({@link #close close} was invoked).
+ *
+ *
+ * The returned read-write transaction presents an isolated view of the data if the previous
+ * write transaction was successful - in other words, this read-write transaction will see the
+ * state changes made by the previous write transaction in the chain. However, state which
+ * was introduced by other transactions outside this transaction chain after creation of
+ * the previous transaction is not visible.
+ *
+ *
+ * Committing this read-write transaction using {@link AsyncWriteTransaction#submit submit}
+ * will submit the state changes in this transaction to be visible to any subsequent
+ * transaction in this chain and also to any transaction outside this chain.
+ *
+ * @return New transaction in the chain.
+ * @throws IllegalStateException
+ * if the previous transaction was not SUBMITTED or CANCELLED.
+ * @throws TransactionChainClosedException
+ * if the chain has been closed.
+ */
+ @Override
+ AsyncReadWriteTransaction
+ * The previous write transaction has to be either SUBMITTED
+ * ({@link AsyncWriteTransaction#submit submit} was invoked) or CANCELLED
+ * ({@link #close close} was invoked).
+ *
+ *
+ * The returned write-only transaction presents an isolated view of the data if the previous
+ * write transaction was successful - in other words, this write-only transaction will see the
+ * state changes made by the previous write transaction in the chain. However, state which
+ * was introduced by other transactions outside this transaction chain after creation of
+ * the previous transaction is not visible.
+ *
+ *
+ * Committing this write-only transaction using {@link AsyncWriteTransaction#submit submit}
+ * will submit the state changes in this transaction to be visible to any subsequent
+ * transaction in this chain and also to any transaction outside this chain.
+ *
+ * @return New transaction in the chain.
+ * @throws IllegalStateException
+ * if the previous transaction was not SUBMITTED or CANCELLED.
+ * @throws TransactionChainClosedException
+ * if the chain has been closed.
+ */
+ @Override
+ AsyncWriteTransaction