Correct annotations
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / databroker / actors / dds / ProxyHistory.java
index 07fcbebad01a263d38a0bfabe839e8b02832ffe2..92284e05a2fcef37edfa4362380279514f154d9c 100644 (file)
@@ -7,22 +7,32 @@
  */
 package org.opendaylight.controller.cluster.databroker.actors.dds;
 
+import static com.google.common.base.Preconditions.checkState;
+import static java.util.Objects.requireNonNull;
+
 import akka.actor.ActorRef;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Verify;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import java.util.Collection;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
-import java.util.function.BiConsumer;
 import java.util.function.Consumer;
-import javax.annotation.concurrent.GuardedBy;
+import org.checkerframework.checker.lock.qual.GuardedBy;
+import org.checkerframework.checker.lock.qual.Holding;
+import org.eclipse.jdt.annotation.NonNull;
 import org.opendaylight.controller.cluster.access.client.AbstractClientConnection;
+import org.opendaylight.controller.cluster.access.client.ClientActorContext;
 import org.opendaylight.controller.cluster.access.client.ConnectedClientConnection;
+import org.opendaylight.controller.cluster.access.client.ConnectionEntry;
+import org.opendaylight.controller.cluster.access.commands.CreateLocalHistoryRequest;
+import org.opendaylight.controller.cluster.access.commands.DestroyLocalHistoryRequest;
 import org.opendaylight.controller.cluster.access.commands.LocalHistoryRequest;
+import org.opendaylight.controller.cluster.access.commands.PurgeLocalHistoryRequest;
 import org.opendaylight.controller.cluster.access.commands.TransactionRequest;
 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
 import org.opendaylight.controller.cluster.access.concepts.Request;
@@ -30,9 +40,8 @@ import org.opendaylight.controller.cluster.access.concepts.RequestException;
 import org.opendaylight.controller.cluster.access.concepts.Response;
 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
 import org.opendaylight.yangtools.concepts.Identifiable;
-import org.opendaylight.yangtools.yang.data.api.schema.tree.CursorAwareDataTreeModification;
-import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.ReadOnlyDataTree;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -43,12 +52,12 @@ import org.slf4j.LoggerFactory;
  */
 abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
     private abstract static class AbstractLocal extends ProxyHistory {
-        private final DataTree dataTree;
+        private final ReadOnlyDataTree dataTree;
 
-        AbstractLocal(final AbstractClientConnection<ShardBackendInfo> connection,
-            final LocalHistoryIdentifier identifier, final DataTree dataTree) {
-            super(connection, identifier);
-            this.dataTree = Preconditions.checkNotNull(dataTree);
+        AbstractLocal(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
+            final LocalHistoryIdentifier identifier, final ReadOnlyDataTree dataTree) {
+            super(parent, connection, identifier);
+            this.dataTree = requireNonNull(dataTree);
         }
 
         final DataTreeSnapshot takeSnapshot() {
@@ -57,40 +66,40 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
     }
 
     private abstract static class AbstractRemote extends ProxyHistory {
-        AbstractRemote(final AbstractClientConnection<ShardBackendInfo> connection,
+        AbstractRemote(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
             final LocalHistoryIdentifier identifier) {
-            super(connection, identifier);
-        }
-
-        @Override
-        final AbstractProxyTransaction doCreateTransactionProxy(
-                final AbstractClientConnection<ShardBackendInfo> connection, final TransactionIdentifier txId) {
-            return new RemoteProxyTransaction(this, txId);
+            super(parent, connection, identifier);
         }
     }
 
     private static final class Local extends AbstractLocal {
-        private static final AtomicReferenceFieldUpdater<Local, LocalProxyTransaction> LAST_SEALED_UPDATER =
-                AtomicReferenceFieldUpdater.newUpdater(Local.class, LocalProxyTransaction.class, "lastSealed");
+        private static final AtomicReferenceFieldUpdater<Local, LocalReadWriteProxyTransaction> LAST_SEALED_UPDATER =
+                AtomicReferenceFieldUpdater.newUpdater(Local.class, LocalReadWriteProxyTransaction.class, "lastSealed");
 
         // Tracks the last open and last sealed transaction. We need to track both in case the user ends up aborting
         // the open one and attempts to create a new transaction again.
-        private LocalProxyTransaction lastOpen;
+        private LocalReadWriteProxyTransaction lastOpen;
 
-        private volatile LocalProxyTransaction lastSealed;
+        private volatile LocalReadWriteProxyTransaction lastSealed;
 
-        Local(final AbstractClientConnection<ShardBackendInfo> connection, final LocalHistoryIdentifier identifier,
-            final DataTree dataTree) {
-            super(connection, identifier, dataTree);
+        Local(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
+            final LocalHistoryIdentifier identifier, final ReadOnlyDataTree dataTree) {
+            super(parent, connection, identifier, dataTree);
         }
 
         @Override
         AbstractProxyTransaction doCreateTransactionProxy(final AbstractClientConnection<ShardBackendInfo> connection,
-                final TransactionIdentifier txId) {
-            Preconditions.checkState(lastOpen == null, "Proxy %s has %s currently open", this, lastOpen);
+                final TransactionIdentifier txId, final boolean snapshotOnly, final boolean isDone) {
+            checkState(lastOpen == null, "Proxy %s has %s currently open", this, lastOpen);
+
+            if (isDone) {
+                // Done transactions do not register on our radar on should not have any state associated.
+                return snapshotOnly ? new LocalReadOnlyProxyTransaction(this, txId)
+                        : new LocalReadWriteProxyTransaction(this, txId);
+            }
 
             // onTransactionCompleted() runs concurrently
-            final LocalProxyTransaction localSealed = lastSealed;
+            final LocalReadWriteProxyTransaction localSealed = lastSealed;
             final DataTreeSnapshot baseSnapshot;
             if (localSealed != null) {
                 baseSnapshot = localSealed.getSnapshot();
@@ -98,79 +107,97 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
                 baseSnapshot = takeSnapshot();
             }
 
-            lastOpen = new LocalProxyTransaction(this, txId,
-                (CursorAwareDataTreeModification) baseSnapshot.newModification());
+            if (snapshotOnly) {
+                return new LocalReadOnlyProxyTransaction(this, txId, baseSnapshot);
+            }
+
+            lastOpen = new LocalReadWriteProxyTransaction(this, txId, baseSnapshot);
             LOG.debug("Proxy {} open transaction {}", this, lastOpen);
             return lastOpen;
         }
 
         @Override
         ProxyHistory createSuccessor(final AbstractClientConnection<ShardBackendInfo> connection) {
-            return createClient(connection, getIdentifier());
+            return createClient(parent(), connection, getIdentifier());
         }
 
         @Override
         void onTransactionAborted(final AbstractProxyTransaction tx) {
-            Preconditions.checkState(tx.equals(lastOpen));
-            lastOpen = null;
+            if (tx.equals(lastOpen)) {
+                lastOpen = null;
+            }
         }
 
         @Override
         void onTransactionCompleted(final AbstractProxyTransaction tx) {
             Verify.verify(tx instanceof LocalProxyTransaction);
-
-            if (LAST_SEALED_UPDATER.compareAndSet(this, (LocalProxyTransaction) tx, null)) {
+            if (tx instanceof LocalReadWriteProxyTransaction
+                    && LAST_SEALED_UPDATER.compareAndSet(this, (LocalReadWriteProxyTransaction) tx, null)) {
                 LOG.debug("Completed last sealed transaction {}", tx);
             }
         }
 
         @Override
         void onTransactionSealed(final AbstractProxyTransaction tx) {
-            Preconditions.checkState(tx.equals(lastOpen));
+            checkState(tx.equals(lastOpen));
             lastSealed = lastOpen;
             lastOpen = null;
         }
     }
 
     private static final class LocalSingle extends AbstractLocal {
-        LocalSingle(final AbstractClientConnection<ShardBackendInfo> connection,
-            final LocalHistoryIdentifier identifier, final DataTree dataTree) {
-            super(connection, identifier, dataTree);
+        LocalSingle(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
+            final LocalHistoryIdentifier identifier, final ReadOnlyDataTree dataTree) {
+            super(parent, connection, identifier, dataTree);
         }
 
         @Override
         AbstractProxyTransaction doCreateTransactionProxy(final AbstractClientConnection<ShardBackendInfo> connection,
-                final TransactionIdentifier txId) {
-            return new LocalProxyTransaction(this, txId,
-                (CursorAwareDataTreeModification) takeSnapshot().newModification());
+                final TransactionIdentifier txId, final boolean snapshotOnly, final boolean isDone) {
+            final DataTreeSnapshot snapshot = takeSnapshot();
+            return snapshotOnly ? new LocalReadOnlyProxyTransaction(this, txId, snapshot) :
+                new LocalReadWriteProxyTransaction(this, txId, snapshot);
         }
 
         @Override
         ProxyHistory createSuccessor(final AbstractClientConnection<ShardBackendInfo> connection) {
-            return createSingle(connection, getIdentifier());
+            return createSingle(parent(), connection, getIdentifier());
         }
     }
 
     private static final class Remote extends AbstractRemote {
-        Remote(final AbstractClientConnection<ShardBackendInfo> connection, final LocalHistoryIdentifier identifier) {
-            super(connection, identifier);
+        Remote(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
+            final LocalHistoryIdentifier identifier) {
+            super(parent, connection, identifier);
+        }
+
+        @Override
+        AbstractProxyTransaction doCreateTransactionProxy(final AbstractClientConnection<ShardBackendInfo> connection,
+                final TransactionIdentifier txId, final boolean snapshotOnly, final boolean isDone) {
+            return new RemoteProxyTransaction(this, txId, snapshotOnly, true, isDone);
         }
 
         @Override
         ProxyHistory createSuccessor(final AbstractClientConnection<ShardBackendInfo> connection) {
-            return createClient(connection, getIdentifier());
+            return createClient(parent(), connection, getIdentifier());
         }
     }
 
     private static final class RemoteSingle extends AbstractRemote {
-        RemoteSingle(final AbstractClientConnection<ShardBackendInfo> connection,
+        RemoteSingle(final AbstractClientHistory parent, final AbstractClientConnection<ShardBackendInfo> connection,
             final LocalHistoryIdentifier identifier) {
-            super(connection, identifier);
+            super(parent, connection, identifier);
+        }
+
+        @Override
+        AbstractProxyTransaction doCreateTransactionProxy(final AbstractClientConnection<ShardBackendInfo> connection,
+                final TransactionIdentifier txId, final boolean snapshotOnly, final boolean isDone) {
+            return new RemoteProxyTransaction(this, txId, snapshotOnly, false, isDone);
         }
 
         @Override
         ProxyHistory createSuccessor(final AbstractClientConnection<ShardBackendInfo> connection) {
-            return createSingle(connection, getIdentifier());
+            return createSingle(parent(), connection, getIdentifier());
         }
     }
 
@@ -193,14 +220,42 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
             return identifier;
         }
 
-        @GuardedBy("lock")
+        @Holding("lock")
         @Override
-        void replaySuccessfulRequests() {
+        void replayRequests(final Collection<ConnectionEntry> previousEntries) {
+            // First look for our Create message
+            Iterator<ConnectionEntry> it = previousEntries.iterator();
+            while (it.hasNext()) {
+                final ConnectionEntry e = it.next();
+                final Request<?, ?> req = e.getRequest();
+                if (identifier.equals(req.getTarget())) {
+                    Verify.verify(req instanceof LocalHistoryRequest);
+                    if (req instanceof CreateLocalHistoryRequest) {
+                        successor.connection.enqueueRequest(req, e.getCallback(), e.getEnqueuedTicks());
+                        it.remove();
+                        break;
+                    }
+                }
+            }
+
             for (AbstractProxyTransaction t : proxies.values()) {
-                LOG.debug("{} creating successor transaction proxy for {}", identifier, t);
-                final AbstractProxyTransaction newProxy = successor.createTransactionProxy(t.getIdentifier());
-                LOG.debug("{} created successor transaction proxy {}", identifier, newProxy);
-                t.startReconnect(newProxy);
+                LOG.debug("{} replaying messages to old proxy {} towards successor {}", identifier, t, successor);
+                t.replayMessages(successor, previousEntries);
+            }
+
+            // Now look for any finalizing messages
+            it = previousEntries.iterator();
+            while (it.hasNext()) {
+                final ConnectionEntry e  = it.next();
+                final Request<?, ?> req = e.getRequest();
+                if (identifier.equals(req.getTarget())) {
+                    Verify.verify(req instanceof LocalHistoryRequest);
+                    if (req instanceof DestroyLocalHistoryRequest) {
+                        successor.connection.enqueueRequest(req, e.getCallback(), e.getEnqueuedTicks());
+                        it.remove();
+                        break;
+                    }
+                }
             }
         }
 
@@ -219,20 +274,34 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
         }
 
         @Override
-        void replayRequest(final Request<?, ?> request, final Consumer<Response<?, ?>> callback,
-                final BiConsumer<Request<?, ?>, Consumer<Response<?, ?>>> replayTo) throws RequestException {
+        void replayEntry(final ConnectionEntry entry, final Consumer<ConnectionEntry> replayTo)
+                throws RequestException {
+            final Request<?, ?> request = entry.getRequest();
             if (request instanceof TransactionRequest) {
-                replayTransactionRequest((TransactionRequest<?>) request, callback);
+                lookupProxy(request).replayRequest((TransactionRequest<?>) request, entry.getCallback(),
+                    entry.getEnqueuedTicks());
             } else if (request instanceof LocalHistoryRequest) {
-                replayTo.accept(request, callback);
+                replayTo.accept(entry);
             } else {
                 throw new IllegalArgumentException("Unhandled request " + request);
             }
         }
 
-        private void replayTransactionRequest(final TransactionRequest<?> request,
-                final Consumer<Response<?, ?>> callback) throws RequestException {
+        @Override
+        void forwardEntry(final ConnectionEntry entry, final Consumer<ConnectionEntry> forwardTo)
+                throws RequestException {
+            final Request<?, ?> request = entry.getRequest();
+            if (request instanceof TransactionRequest) {
+                lookupProxy(request).forwardRequest((TransactionRequest<?>) request, entry.getCallback());
+            } else if (request instanceof LocalHistoryRequest) {
+                forwardTo.accept(entry);
+            } else {
+                throw new IllegalArgumentException("Unhandled request " + request);
+            }
+        }
 
+        private AbstractProxyTransaction lookupProxy(final Request<?, ?> request)
+                throws RequestReplayException {
             final AbstractProxyTransaction proxy;
             lock.lock();
             try {
@@ -240,43 +309,46 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
             } finally {
                 lock.unlock();
             }
-            if (proxy == null) {
-                throw new RequestReplayException("Failed to find proxy for %s", request);
+            if (proxy != null) {
+                return proxy;
             }
 
-            proxy.replayRequest(request, callback);
+            throw new RequestReplayException("Failed to find proxy for %s", request);
         }
     }
 
     private static final Logger LOG = LoggerFactory.getLogger(ProxyHistory.class);
 
     private final Lock lock = new ReentrantLock();
-    private final LocalHistoryIdentifier identifier;
-    private final AbstractClientConnection<ShardBackendInfo> connection;
+    private final @NonNull LocalHistoryIdentifier identifier;
+    private final @NonNull AbstractClientConnection<ShardBackendInfo> connection;
+    private final @NonNull AbstractClientHistory parent;
 
     @GuardedBy("lock")
     private final Map<TransactionIdentifier, AbstractProxyTransaction> proxies = new LinkedHashMap<>();
     @GuardedBy("lock")
     private ProxyHistory successor;
 
-    private ProxyHistory(final AbstractClientConnection<ShardBackendInfo> connection,
-            final LocalHistoryIdentifier identifier) {
-        this.connection = Preconditions.checkNotNull(connection);
-        this.identifier = Preconditions.checkNotNull(identifier);
+    private ProxyHistory(final AbstractClientHistory parent,
+            final AbstractClientConnection<ShardBackendInfo> connection, final LocalHistoryIdentifier identifier) {
+        this.parent = requireNonNull(parent);
+        this.connection = requireNonNull(connection);
+        this.identifier = requireNonNull(identifier);
     }
 
-    static ProxyHistory createClient(final AbstractClientConnection<ShardBackendInfo> connection,
-            final LocalHistoryIdentifier identifier) {
-        final Optional<DataTree> dataTree = connection.getBackendInfo().flatMap(ShardBackendInfo::getDataTree);
-        return dataTree.isPresent() ? new Local(connection, identifier, dataTree.get())
-             : new Remote(connection, identifier);
+    static ProxyHistory createClient(final AbstractClientHistory parent,
+            final AbstractClientConnection<ShardBackendInfo> connection, final LocalHistoryIdentifier identifier) {
+        final Optional<ReadOnlyDataTree> dataTree = connection.getBackendInfo().flatMap(ShardBackendInfo::getDataTree);
+        return dataTree.isPresent() ? new Local(parent, connection, identifier, dataTree.get())
+             : new Remote(parent, connection, identifier);
     }
 
-    static ProxyHistory createSingle(final AbstractClientConnection<ShardBackendInfo> connection,
+    static ProxyHistory createSingle(final AbstractClientHistory parent,
+            final AbstractClientConnection<ShardBackendInfo> connection,
             final LocalHistoryIdentifier identifier) {
-        final Optional<DataTree> dataTree = connection.getBackendInfo().flatMap(ShardBackendInfo::getDataTree);
-        return dataTree.isPresent() ? new LocalSingle(connection, identifier, dataTree.get())
-             : new RemoteSingle(connection, identifier);
+        final Optional<ReadOnlyDataTree> dataTree = connection.getBackendInfo().flatMap(ShardBackendInfo::getDataTree);
+        return dataTree.isPresent() ? new LocalSingle(parent, connection, identifier, dataTree.get())
+             : new RemoteSingle(parent, connection, identifier);
     }
 
     @Override
@@ -284,19 +356,37 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
         return identifier;
     }
 
+    final ClientActorContext context() {
+        return connection.context();
+    }
+
+    final long currentTime() {
+        return connection.currentTime();
+    }
+
     final ActorRef localActor() {
         return connection.localActor();
     }
 
-    final AbstractProxyTransaction createTransactionProxy(final TransactionIdentifier txId) {
+    final AbstractClientHistory parent() {
+        return parent;
+    }
+
+    final AbstractProxyTransaction createTransactionProxy(final TransactionIdentifier txId,
+            final boolean snapshotOnly) {
+        return createTransactionProxy(txId, snapshotOnly, false);
+    }
+
+    AbstractProxyTransaction createTransactionProxy(final TransactionIdentifier txId, final boolean snapshotOnly,
+            final boolean isDone) {
         lock.lock();
         try {
             if (successor != null) {
-                return successor.createTransactionProxy(txId);
+                return successor.createTransactionProxy(txId, snapshotOnly, isDone);
             }
 
             final TransactionIdentifier proxyId = new TransactionIdentifier(identifier, txId.getTransactionId());
-            final AbstractProxyTransaction ret = doCreateTransactionProxy(connection, proxyId);
+            final AbstractProxyTransaction ret = doCreateTransactionProxy(connection, proxyId, snapshotOnly, isDone);
             proxies.put(proxyId, ret);
             LOG.debug("Allocated proxy {} for transaction {}", proxyId, txId);
             return ret;
@@ -308,8 +398,8 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
     final void abortTransaction(final AbstractProxyTransaction tx) {
         lock.lock();
         try {
-            proxies.remove(tx.getIdentifier());
-            LOG.debug("Proxy {} aborting transaction {}", this, tx);
+            // Removal will be completed once purge completes
+            LOG.debug("Proxy {} aborted transaction {}", this, tx);
             onTransactionAborted(tx);
         } finally {
             lock.unlock();
@@ -319,7 +409,7 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
     final void completeTransaction(final AbstractProxyTransaction tx) {
         lock.lock();
         try {
-            proxies.remove(tx.getIdentifier());
+            // Removal will be completed once purge completes
             LOG.debug("Proxy {} completing transaction {}", this, tx);
             onTransactionCompleted(tx);
         } finally {
@@ -327,14 +417,48 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
         }
     }
 
+    void purgeTransaction(final AbstractProxyTransaction tx) {
+        lock.lock();
+        try {
+            proxies.remove(tx.getIdentifier());
+            LOG.debug("Proxy {} purged transaction {}", this, tx);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    final void close() {
+        lock.lock();
+        try {
+            if (successor != null) {
+                successor.close();
+                return;
+            }
+
+            LOG.debug("Proxy {} invoking destroy", this);
+            connection.sendRequest(new DestroyLocalHistoryRequest(getIdentifier(), 1, localActor()),
+                this::onDestroyComplete);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    final void enqueueRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback,
+            final long enqueuedTicks) {
+        connection.enqueueRequest(request, callback, enqueuedTicks);
+    }
+
     final void sendRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback) {
         connection.sendRequest(request, callback);
     }
 
-    @GuardedBy("lock")
+    @Holding("lock")
+    @SuppressWarnings("checkstyle:hiddenField")
     abstract AbstractProxyTransaction doCreateTransactionProxy(AbstractClientConnection<ShardBackendInfo> connection,
-            TransactionIdentifier txId);
+            TransactionIdentifier txId, boolean snapshotOnly, boolean isDone);
 
+    @Holding("lock")
+    @SuppressWarnings("checkstyle:hiddenField")
     abstract ProxyHistory createSuccessor(AbstractClientConnection<ShardBackendInfo> connection);
 
     @SuppressFBWarnings(value = "UL_UNRELEASED_LOCK", justification = "Lock is released asynchronously via the cohort")
@@ -347,15 +471,37 @@ abstract class ProxyHistory implements Identifiable<LocalHistoryIdentifier> {
 
         successor = createSuccessor(newConnection);
         LOG.debug("History {} instantiated successor {}", this, successor);
+
+        for (AbstractProxyTransaction t : proxies.values()) {
+            t.startReconnect();
+        }
+
         return new ReconnectCohort();
     }
 
-    @GuardedBy("lock")
+    private void onDestroyComplete(final Response<?, ?> response) {
+        LOG.debug("Proxy {} destroy completed with {}", this, response);
+
+        lock.lock();
+        try {
+            parent.onProxyDestroyed(this);
+            connection.sendRequest(new PurgeLocalHistoryRequest(getIdentifier(), 2, localActor()),
+                this::onPurgeComplete);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private void onPurgeComplete(final Response<?, ?> response) {
+        LOG.debug("Proxy {} purge completed with {}", this, response);
+    }
+
+    @Holding("lock")
     void onTransactionAborted(final AbstractProxyTransaction tx) {
         // No-op for most implementations
     }
 
-    @GuardedBy("lock")
+    @Holding("lock")
     void onTransactionCompleted(final AbstractProxyTransaction tx) {
         // No-op for most implementations
     }