*/
package org.opendaylight.controller.md.sal.dom.broker.impl;
-import static com.google.common.base.Preconditions.checkState;
-
-import javax.annotation.concurrent.GuardedBy;
-
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
import org.opendaylight.yangtools.yang.common.RpcResult;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
-
-import com.google.common.base.Preconditions;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.util.concurrent.CheckedFuture;
-import com.google.common.util.concurrent.ListenableFuture;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
- *
- *
* Read-Write Transaction, which is composed of several
- * {@link DOMStoreWriteTransaction} transactions. Subtransaction is selected by
+ * {@link DOMStoreWriteTransaction} transactions. A sub-transaction is selected by
* {@link LogicalDatastoreType} type parameter in:
*
* <ul>
* invocation with all {@link org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort} for underlying
* transactions.
*
- * @param <T>
- * Subtype of {@link DOMStoreWriteTransaction} which is used as
+ * @param <T> Subtype of {@link DOMStoreWriteTransaction} which is used as
* subtransaction.
*/
class DOMForwardedWriteTransaction<T extends DOMStoreWriteTransaction> extends
AbstractDOMForwardedCompositeTransaction<LogicalDatastoreType, T> implements DOMDataWriteTransaction {
+ @SuppressWarnings("rawtypes")
+ private static final AtomicReferenceFieldUpdater<DOMForwardedWriteTransaction, DOMDataCommitImplementation> IMPL_UPDATER =
+ AtomicReferenceFieldUpdater.newUpdater(DOMForwardedWriteTransaction.class, DOMDataCommitImplementation.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.
- *
- * Transaction can not be commited if commitImpl is null,
- * so this seting this property to null is also used to
- * prevent write to
- * already commited / canceled transaction {@link #checkNotCanceled()
- *
- *
+ * Implementation of real commit. It also acts as an indication that
+ * the transaction is running -- which we flip atomically using
+ * {@link #IMPL_UPDATER}.
*/
- @GuardedBy("this")
private volatile DOMDataCommitImplementation 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)}.
*
- * Future task of transaction commit.
- *
- * This value is initially null, and is once updated if transaction
- * is commited {@link #commit()}.
- * If this future exists, transaction MUST not be commited again
- * and all modifications should fail. See {@link #checkNotCommited()}.
- *
+ * 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.
*/
- @GuardedBy("this")
- private volatile CheckedFuture<Void, TransactionCommitFailedException> commitFuture;
+ private volatile Future<?> commitFuture;
protected DOMForwardedWriteTransaction(final Object identifier,
final ImmutableMap<LogicalDatastoreType, T> backingTxs, final DOMDataCommitImplementation commitImpl) {
@Override
public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
- checkNotReady();
+ checkRunning(commitImpl);
getSubtransaction(store).write(path, data);
}
@Override
public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
- checkNotReady();
+ checkRunning(commitImpl);
getSubtransaction(store).delete(path);
}
@Override
public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
- checkNotReady();
+ checkRunning(commitImpl);
getSubtransaction(store).merge(path, data);
}
@Override
- public synchronized boolean cancel() {
- // Transaction is already canceled, we are safe to return true
- final boolean cancelationResult;
- if (commitImpl == null && commitFuture != null) {
- // Transaction is submitted, we try to cancel future.
- cancelationResult = commitFuture.cancel(false);
- } else if(commitImpl == null) {
+ public boolean cancel() {
+ final DOMDataCommitImplementation impl = IMPL_UPDATER.getAndSet(this, null);
+ if (impl != null) {
+ LOG.trace("Transaction {} cancelled before submit", getIdentifier());
+ FUTURE_UPDATER.lazySet(this, CANCELLED_FUTURE);
return true;
- } else {
- cancelationResult = true;
- commitImpl = null;
}
- return cancelationResult;
+ // The transaction is in process of being submitted or cancelled. Busy-wait
+ // for the corresponding future.
+ Future<?> future;
+ do {
+ future = commitFuture;
+ } while (future == null);
+
+ return future.cancel(false);
}
@Override
- public synchronized ListenableFuture<RpcResult<TransactionStatus>> commit() {
+ public ListenableFuture<RpcResult<TransactionStatus>> commit() {
return AbstractDataTransaction.convertToLegacyCommitFuture(submit());
}
@Override
- public CheckedFuture<Void,TransactionCommitFailedException> submit() {
- checkNotReady();
+ public CheckedFuture<Void, TransactionCommitFailedException> submit() {
+ final DOMDataCommitImplementation impl = IMPL_UPDATER.getAndSet(this, null);
+ checkRunning(impl);
- ImmutableList.Builder<DOMStoreThreePhaseCommitCohort> cohortsBuilder = ImmutableList.builder();
- for (DOMStoreWriteTransaction subTx : getSubtransactions()) {
- cohortsBuilder.add(subTx.ready());
- }
- ImmutableList<DOMStoreThreePhaseCommitCohort> cohorts = cohortsBuilder.build();
- commitFuture = commitImpl.submit(this, cohorts);
-
- /*
- *We remove reference to Commit Implementation in order
- *to prevent memory leak
- */
- commitImpl = null;
- return commitFuture;
- }
+ final Collection<T> txns = getSubtransactions();
+ final Collection<DOMStoreThreePhaseCommitCohort> cohorts = new ArrayList<>(txns.size());
- private void checkNotReady() {
- checkNotCommited();
- checkNotCanceled();
- }
+ // FIXME: deal with errors thrown by backed (ready and submit can fail in theory)
+ for (DOMStoreWriteTransaction txn : txns) {
+ cohorts.add(txn.ready());
+ }
- private void checkNotCanceled() {
- Preconditions.checkState(commitImpl != null, "Transaction was canceled.");
+ final CheckedFuture<Void, TransactionCommitFailedException> ret = impl.submit(this, cohorts);
+ FUTURE_UPDATER.lazySet(this, ret);
+ return ret;
}
- private void checkNotCommited() {
- checkState(commitFuture == null, "Transaction was already submited.");
+ private void checkRunning(final DOMDataCommitImplementation impl) {
+ Preconditions.checkState(impl != null, "Transaction %s is no longer running", getIdentifier());
}
-}
\ No newline at end of file
+}
Code Review / controller.git / commitdiff