package org.opendaylight.controller.cluster.datastore;
+import akka.actor.ActorSelection;
+import akka.dispatch.OnComplete;
+import com.google.common.base.Preconditions;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.opendaylight.controller.cluster.datastore.messages.CloseTransactionChain;
import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
+import org.opendaylight.controller.md.sal.common.api.data.TransactionChainClosedException;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadTransaction;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreReadWriteTransaction;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreTransactionChain;
import org.opendaylight.controller.sal.core.spi.data.DOMStoreWriteTransaction;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import scala.concurrent.Future;
+import scala.concurrent.Promise;
/**
* TransactionChainProxy acts as a proxy for a DOMStoreTransactionChain created on a remote shard
*/
-public class TransactionChainProxy implements DOMStoreTransactionChain{
+public class TransactionChainProxy implements DOMStoreTransactionChain {
+
+ private static final Logger LOG = LoggerFactory.getLogger(TransactionChainProxy.class);
+
+ private interface State {
+ boolean isReady();
+
+ List<Future<ActorSelection>> getPreviousReadyFutures();
+ }
+
+ private static class Allocated implements State {
+ private final ChainedTransactionProxy transaction;
+
+ Allocated(ChainedTransactionProxy transaction) {
+ this.transaction = transaction;
+ }
+
+ @Override
+ public boolean isReady() {
+ return transaction.isReady();
+ }
+
+ @Override
+ public List<Future<ActorSelection>> getPreviousReadyFutures() {
+ return transaction.getReadyFutures();
+ }
+ }
+
+ private static abstract class AbstractDefaultState implements State {
+ @Override
+ public List<Future<ActorSelection>> getPreviousReadyFutures() {
+ return Collections.emptyList();
+ }
+ }
+
+ private static final State IDLE_STATE = new AbstractDefaultState() {
+ @Override
+ public boolean isReady() {
+ return true;
+ }
+ };
+
+ private static final State CLOSED_STATE = new AbstractDefaultState() {
+ @Override
+ public boolean isReady() {
+ throw new TransactionChainClosedException("Transaction chain has been closed");
+ }
+ };
+
+ private static final AtomicInteger counter = new AtomicInteger(0);
+
private final ActorContext actorContext;
+ private final String transactionChainId;
+ private volatile State currentState = IDLE_STATE;
public TransactionChainProxy(ActorContext actorContext) {
this.actorContext = actorContext;
+ transactionChainId = actorContext.getCurrentMemberName() + "-txn-chain-" + counter.incrementAndGet();
+ }
+
+ public String getTransactionChainId() {
+ return transactionChainId;
}
@Override
public DOMStoreReadTransaction newReadOnlyTransaction() {
- return new TransactionProxy(actorContext,
- TransactionProxy.TransactionType.READ_ONLY);
+ State localState = currentState;
+ checkReadyState(localState);
+
+ return new ChainedTransactionProxy(actorContext, TransactionProxy.TransactionType.READ_ONLY,
+ transactionChainId, localState.getPreviousReadyFutures());
}
@Override
public DOMStoreReadWriteTransaction newReadWriteTransaction() {
- return new TransactionProxy(actorContext,
- TransactionProxy.TransactionType.WRITE_ONLY);
+ return allocateWriteTransaction(TransactionProxy.TransactionType.READ_WRITE);
}
@Override
public DOMStoreWriteTransaction newWriteOnlyTransaction() {
- return new TransactionProxy(actorContext,
- TransactionProxy.TransactionType.READ_WRITE);
+ return allocateWriteTransaction(TransactionProxy.TransactionType.WRITE_ONLY);
}
@Override
public void close() {
- // FIXME : The problem here is don't know which shard the transaction chain is to be created on ???
- throw new UnsupportedOperationException("close - not sure what to do here?");
+ currentState = CLOSED_STATE;
+
+ // Send a close transaction chain request to each and every shard
+ actorContext.broadcast(new CloseTransactionChain(transactionChainId));
+ }
+
+ private ChainedTransactionProxy allocateWriteTransaction(TransactionProxy.TransactionType type) {
+ State localState = currentState;
+
+ checkReadyState(localState);
+
+ // Pass the ready Futures from the previous Tx.
+ ChainedTransactionProxy txProxy = new ChainedTransactionProxy(actorContext, type,
+ transactionChainId, localState.getPreviousReadyFutures());
+
+ currentState = new Allocated(txProxy);
+
+ return txProxy;
+ }
+
+ private void checkReadyState(State state) {
+ Preconditions.checkState(state.isReady(), "Previous transaction is not ready yet");
+ }
+
+ private static class ChainedTransactionProxy extends TransactionProxy {
+
+ /**
+ * Stores the ready Futures from the previous Tx in the chain.
+ */
+ private final List<Future<ActorSelection>> previousReadyFutures;
+
+ /**
+ * Stores the ready Futures from this transaction when it is readied.
+ */
+ private volatile List<Future<ActorSelection>> readyFutures;
+
+ private ChainedTransactionProxy(ActorContext actorContext, TransactionType transactionType,
+ String transactionChainId, List<Future<ActorSelection>> previousReadyFutures) {
+ super(actorContext, transactionType, transactionChainId);
+ this.previousReadyFutures = previousReadyFutures;
+ }
+
+ List<Future<ActorSelection>> getReadyFutures() {
+ return readyFutures;
+ }
+
+ boolean isReady() {
+ return readyFutures != null;
+ }
+
+ @Override
+ protected void onTransactionReady(List<Future<ActorSelection>> readyFutures) {
+ LOG.debug("onTransactionReady {} pending readyFutures size {} chain {}", getIdentifier(),
+ readyFutures.size(), getTransactionChainId());
+ this.readyFutures = readyFutures;
+ }
+
+ /**
+ * This method is overridden to ensure the previous Tx's ready operations complete
+ * before we create the next shard Tx in the chain to avoid creation failures if the
+ * previous Tx's ready operations haven't completed yet.
+ */
+ @Override
+ protected Future<Object> sendCreateTransaction(final ActorSelection shard,
+ final Object serializedCreateMessage) {
+
+ // Check if there are any previous ready Futures, otherwise let the super class handle it.
+ if(previousReadyFutures.isEmpty()) {
+ return super.sendCreateTransaction(shard, serializedCreateMessage);
+ }
+
+ // Combine the ready Futures into 1.
+ Future<Iterable<ActorSelection>> combinedFutures = akka.dispatch.Futures.sequence(
+ previousReadyFutures, getActorContext().getActorSystem().dispatcher());
+
+ // Add a callback for completion of the combined Futures.
+ final Promise<Object> createTxPromise = akka.dispatch.Futures.promise();
+ OnComplete<Iterable<ActorSelection>> onComplete = new OnComplete<Iterable<ActorSelection>>() {
+ @Override
+ public void onComplete(Throwable failure, Iterable<ActorSelection> notUsed) {
+ if(failure != null) {
+ // A Ready Future failed so fail the returned Promise.
+ createTxPromise.failure(failure);
+ } else {
+ LOG.debug("Previous Tx readied - sending CreateTransaction for {} on chain {}",
+ getIdentifier(), getTransactionChainId());
+
+ // Send the CreateTx message and use the resulting Future to complete the
+ // returned Promise.
+ createTxPromise.completeWith(getActorContext().executeOperationAsync(shard,
+ serializedCreateMessage));
+ }
+ }
+ };
+
+ combinedFutures.onComplete(onComplete, getActorContext().getActorSystem().dispatcher());
+
+ return createTxPromise.future();
+ }
}
}