Use transactional database API in Bramble.

bramble-api/src/main/java/org/briarproject/bramble/api/Maybe.java

@@ -0,0 +1,33 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.NoSuchElementException;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Minimal stand-in for `java.util.Optional`. Functionality from `Optional`
+ * can be added as needed.
+ */
+@Immutable
+@NotNullByDefault
+public class Maybe<T> {
+
+	@Nullable
+	private final T value;
+
+	public Maybe(@Nullable T value) {
+		this.value = value;
+	}
+
+	public boolean isPresent() {
+		return value != null;
+	}
+
+	public T get() {
+		if (value == null) throw new NoSuchElementException();
+		return value;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/Pair.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class Pair<A, B> {
+
+	private final A first;
+	private final B second;
+
+	public Pair(A first, B second) {
+		this.first = first;
+		this.second = second;
+	}
+
+	public A getFirst() {
+		return first;
+	}
+
+	public B getSecond() {
+		return second;
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/client/ClientHelperImpl.java

@@ -82,13 +82,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void addLocalMessage(Message m, BdfDictionary metadata,
 			boolean shared) throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> addLocalMessage(txn, m, metadata, shared));
-		try {
-			addLocalMessage(txn, m, metadata, shared);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
@@ -113,15 +107,7 @@ class ClientHelperImpl implements ClientHelper {
 
 	@Override
 	public Message getMessage(MessageId m) throws DbException {
-		Message message;
+		return db.transactionWithResult(true, txn -> getMessage(txn, m));
-		Transaction txn = db.startTransaction(true);
-		try {
-			message = getMessage(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return message;
 	}
 
 	@Override
@@ -132,15 +118,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfList getMessageAsList(MessageId m) throws DbException,
 			FormatException {
-		BdfList list;
+		return db.transactionWithResult(true, txn -> getMessageAsList(txn, m));
-		Transaction txn = db.startTransaction(true);
-		try {
-			list = getMessageAsList(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return list;
 	}
 
 	@Override
@@ -152,15 +130,8 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfDictionary getGroupMetadataAsDictionary(GroupId g)
 			throws DbException, FormatException {
-		BdfDictionary dictionary;
+		return db.transactionWithResult(true, txn ->
-		Transaction txn = db.startTransaction(true);
+				getGroupMetadataAsDictionary(txn, g));
-		try {
-			dictionary = getGroupMetadataAsDictionary(txn, g);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return dictionary;
 	}
 
 	@Override
@@ -173,15 +144,8 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfDictionary getMessageMetadataAsDictionary(MessageId m)
 			throws DbException, FormatException {
-		BdfDictionary dictionary;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> getMessageMetadataAsDictionary(txn, m));
-		try {
-			dictionary = getMessageMetadataAsDictionary(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return dictionary;
 	}
 
 	@Override
@@ -194,15 +158,8 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g) throws DbException, FormatException {
-		Map<MessageId, BdfDictionary> map;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> getMessageMetadataAsDictionary(txn, g));
-		try {
-			map = getMessageMetadataAsDictionary(txn, g);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return map;
 	}
 
 	@Override
@@ -219,15 +176,8 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g, BdfDictionary query) throws DbException,
 			FormatException {
-		Map<MessageId, BdfDictionary> map;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> getMessageMetadataAsDictionary(txn, g, query));
-		try {
-			map = getMessageMetadataAsDictionary(txn, g, query);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return map;
 	}
 
 	@Override
@@ -245,13 +195,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeGroupMetadata(GroupId g, BdfDictionary metadata)
 			throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> mergeGroupMetadata(txn, g, metadata));
-		try {
-			mergeGroupMetadata(txn, g, metadata);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
@@ -263,13 +207,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeMessageMetadata(MessageId m, BdfDictionary metadata)
 			throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> mergeMessageMetadata(txn, m, metadata));
-		try {
-			mergeMessageMetadata(txn, m, metadata);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -13,7 +13,6 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -158,7 +157,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 				streamWriterFactory.createContactExchangeStreamWriter(out,
 						alice ? aliceHeaderKey : bobHeaderKey);
 		RecordWriter recordWriter =
-				recordWriterFactory.createRecordWriter(streamWriter.getOutputStream());
+				recordWriterFactory
+						.createRecordWriter(streamWriter.getOutputStream());
 
 		// Derive the nonces to be signed
 		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
@@ -287,19 +287,14 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private ContactId addContact(Author remoteAuthor, long timestamp,
 			Map<TransportId, TransportProperties> remoteProperties)
 			throws DbException {
-		ContactId contactId;
+		return db.transactionWithResult(false, txn -> {
-		Transaction txn = db.startTransaction(false);
+			ContactId contactId = contactManager.addContact(txn, remoteAuthor,
-		try {
-			contactId = contactManager.addContact(txn, remoteAuthor,
 					localAuthor.getId(), masterSecret, timestamp, alice,
 					true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
-			db.commitTransaction(txn);
+			return contactId;
-		} finally {
+		});
-			db.endTransaction(txn);
-		}
-		return contactId;
 	}
 
 	private void tryToClose(DuplexTransportConnection conn) {

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -79,42 +79,21 @@ class ContactManagerImpl implements ContactManager {
 	public ContactId addContact(Author remote, AuthorId local, SecretKey master,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException {
-		ContactId c;
+		return db.transactionWithResult(false,
-		Transaction txn = db.startTransaction(false);
+				txn -> addContact(txn, remote, local, master, timestamp, alice,
-		try {
+						verified, active));
-			c = addContact(txn, remote, local, master, timestamp, alice,
-					verified, active);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return c;
 	}
 
 	@Override
 	public Contact getContact(ContactId c) throws DbException {
-		Contact contact;
+		return db.transactionWithResult(true, txn -> db.getContact(txn, c));
-		Transaction txn = db.startTransaction(true);
-		try {
-			contact = db.getContact(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return contact;
 	}
 
 	@Override
 	public Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException {
-		Transaction txn = db.startTransaction(true);
+		return db.transactionWithResult(true,
-		try {
+				txn -> getContact(txn, remoteAuthorId, localAuthorId));
-			Contact c = getContact(txn, remoteAuthorId, localAuthorId);
-			db.commitTransaction(txn);
-			return c;
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
@@ -132,14 +111,8 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public Collection<Contact> getActiveContacts() throws DbException {
-		Collection<Contact> contacts;
+		Collection<Contact> contacts =
-		Transaction txn = db.startTransaction(true);
+				db.transactionWithResult(true, db::getContacts);
-		try {
-			contacts = db.getContacts(txn);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
@@ -147,13 +120,7 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public void removeContact(ContactId c) throws DbException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> removeContact(txn, c));
-		try {
-			removeContact(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
@@ -188,15 +155,8 @@ class ContactManagerImpl implements ContactManager {
 	@Override
 	public boolean contactExists(AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
-		boolean exists;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> contactExists(txn, remoteAuthorId, localAuthorId));
-		try {
-			exists = contactExists(txn, remoteAuthorId, localAuthorId);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return exists;
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/identity/IdentityManagerImpl.java

@@ -67,27 +67,16 @@ class IdentityManagerImpl implements IdentityManager {
 			LOG.info("No local author to store");
 			return;
 		}
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> db.addLocalAuthor(txn, cached));
-		try {
+		LOG.info("Local author stored");
-			db.addLocalAuthor(txn, cached);
-			db.commitTransaction(txn);
-			LOG.info("Local author stored");
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
 	public LocalAuthor getLocalAuthor() throws DbException {
 		if (cachedAuthor == null) {
-			Transaction txn = db.startTransaction(true);
+			cachedAuthor =
-			try {
+					db.transactionWithResult(true, this::loadLocalAuthor);
-				cachedAuthor = loadLocalAuthor(txn);
+			LOG.info("Local author loaded");
-				LOG.info("Local author loaded");
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 		}
 		LocalAuthor cached = cachedAuthor;
 		if (cached == null) throw new AssertionError();

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleManagerImpl.java

@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
@@ -115,20 +114,16 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 			dbLatch.countDown();
 			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));
 
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				for (Client c : clients) {
-					start = now();
+					long start1 = now();
 					c.createLocalState(txn);
 					if (LOG.isLoggable(FINE)) {
 						logDuration(LOG, "Starting client "
-								+ c.getClass().getSimpleName(), start);
+								+ c.getClass().getSimpleName(), start1);
 					}
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 			for (Service s : services) {
 				start = now();
 				s.startService();

bramble-core/src/main/java/org/briarproject/bramble/properties/TransportPropertyManagerImpl.java

@@ -142,15 +142,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<TransportId, TransportProperties> getLocalProperties()
 			throws DbException {
-		Map<TransportId, TransportProperties> local;
+		return db.transactionWithResult(true, this::getLocalProperties);
-		Transaction txn = db.startTransaction(true);
-		try {
-			local = getLocalProperties(txn);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return local;
 	}
 
 	@Override
@@ -176,9 +168,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public TransportProperties getLocalProperties(TransportId t)
 			throws DbException {
 		try {
-			TransportProperties p = null;
+			return db.transactionWithResult(true, txn -> {
-			Transaction txn = db.startTransaction(true);
+				TransportProperties p = null;
-			try {
 				// Find the latest local update
 				LatestUpdate latest = findLatest(txn, localGroup.getId(), t,
 						true);
@@ -188,11 +179,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 							latest.messageId);
 					p = parseProperties(message);
 				}
-				db.commitTransaction(txn);
+				return p == null ? new TransportProperties() : p;
-			} finally {
+			});
-				db.endTransaction(txn);
-			}
-			return p == null ? new TransportProperties() : p;
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}
@@ -201,16 +189,12 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
-		Map<ContactId, TransportProperties> remote = new HashMap<>();
+		return db.transactionWithResult(true, txn -> {
-		Transaction txn = db.startTransaction(true);
+			Map<ContactId, TransportProperties> remote = new HashMap<>();
-		try {
 			for (Contact c : db.getContacts(txn))
 				remote.put(c.getId(), getRemoteProperties(txn, c, t));
-			db.commitTransaction(txn);
+			return remote;
-		} finally {
+		});
-			db.endTransaction(txn);
-		}
-		return remote;
 	}
 
 	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
@@ -234,23 +218,15 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException {
-		TransportProperties p;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> getRemoteProperties(txn, db.getContact(txn, c), t));
-		try {
-			p = getRemoteProperties(txn, db.getContact(txn, c), t);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return p;
 	}
 
 	@Override
 	public void mergeLocalProperties(TransportId t, TransportProperties p)
 			throws DbException {
 		try {
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				// Merge the new properties with any existing properties
 				TransportProperties merged;
 				boolean changed;
@@ -287,10 +263,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 							db.removeMessage(txn, latest.messageId);
 					}
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}

bramble-core/src/main/java/org/briarproject/bramble/settings/SettingsManagerImpl.java

@@ -23,15 +23,8 @@ class SettingsManagerImpl implements SettingsManager {
 
 	@Override
 	public Settings getSettings(String namespace) throws DbException {
-		Settings s;
+		return db.transactionWithResult(true,
-		Transaction txn = db.startTransaction(true);
+				txn -> db.getSettings(txn, namespace));
-		try {
-			s = db.getSettings(txn, namespace);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return s;
 	}
 
 	@Override
@@ -42,12 +35,6 @@ class SettingsManagerImpl implements SettingsManager {
 
 	@Override
 	public void mergeSettings(Settings s, String namespace) throws DbException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> db.mergeSettings(txn, s, namespace));
-		try {
-			db.mergeSettings(txn, s, namespace);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java

@@ -1,11 +1,11 @@
 package org.briarproject.bramble.sync;
 
+import org.briarproject.bramble.api.Maybe;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -230,17 +230,12 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			if (!generateAckQueued.getAndSet(false)) throw new AssertionError();
 			try {
-				Ack a;
+				Maybe<Ack> a = db.transactionWithResult(false,
-				Transaction txn = db.startTransaction(false);
+						txn -> new Maybe<>(db.generateAck(txn, contactId,
-				try {
+								MAX_MESSAGE_IDS)));
-					a = db.generateAck(txn, contactId, MAX_MESSAGE_IDS);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated ack: " + (a != null));
+					LOG.info("Generated ack: " + a.isPresent());
-				if (a != null) writerTasks.add(new WriteAck(a));
+				if (a.isPresent()) writerTasks.add(new WriteAck(a.get()));
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -275,19 +270,16 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateBatchQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Collection<Message> b;
+				Maybe<Collection<Message>>
-				Transaction txn = db.startTransaction(false);
+						b = db.transactionWithResult(false, txn -> {
-				try {
+					Collection<Message> batch = db.generateRequestedBatch(txn,
-					b = db.generateRequestedBatch(txn, contactId,
+							contactId, MAX_RECORD_PAYLOAD_BYTES, maxLatency);
-							MAX_RECORD_PAYLOAD_BYTES, maxLatency);
 					setNextSendTime(db.getNextSendTime(txn, contactId));
-					db.commitTransaction(txn);
+					return new Maybe<>(batch);
-				} finally {
+				});
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated batch: " + (b != null));
+					LOG.info("Generated batch: " + b.isPresent());
-				if (b != null) writerTasks.add(new WriteBatch(b));
+				if (b.isPresent()) writerTasks.add(new WriteBatch(b.get()));
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -322,19 +314,15 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateOfferQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Offer o;
+				Maybe<Offer> o = db.transactionWithResult(false, txn -> {
-				Transaction txn = db.startTransaction(false);
+					Offer offer = db.generateOffer(txn, contactId,
-				try {
+							MAX_MESSAGE_IDS, maxLatency);
-					o = db.generateOffer(txn, contactId, MAX_MESSAGE_IDS,
-							maxLatency);
 					setNextSendTime(db.getNextSendTime(txn, contactId));
-					db.commitTransaction(txn);
+					return new Maybe<>(offer);
-				} finally {
+				});
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated offer: " + (o != null));
+					LOG.info("Generated offer: " + o.isPresent());
-				if (o != null) writerTasks.add(new WriteOffer(o));
+				if (o.isPresent()) writerTasks.add(new WriteOffer(o.get()));
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -369,17 +357,12 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateRequestQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Request r;
+				Maybe<Request> r = db.transactionWithResult(false,
-				Transaction txn = db.startTransaction(false);
+						txn -> new Maybe<>(db.generateRequest(txn, contactId,
-				try {
+								MAX_MESSAGE_IDS)));
-					r = db.generateRequest(txn, contactId, MAX_MESSAGE_IDS);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated request: " + (r != null));
+					LOG.info("Generated request: " + r.isPresent());
-				if (r != null) writerTasks.add(new WriteRequest(r));
+				if (r.isPresent()) writerTasks.add(new WriteRequest(r.get()));
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();

bramble-core/src/main/java/org/briarproject/bramble/sync/IncomingSession.java

@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -120,13 +119,8 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				Transaction txn = db.startTransaction(false);
+				db.transaction(false,
-				try {
+						txn -> db.receiveAck(txn, contactId, ack));
-					db.receiveAck(txn, contactId, ack);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -146,13 +140,8 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				Transaction txn = db.startTransaction(false);
+				db.transaction(false,
-				try {
+						txn -> db.receiveMessage(txn, contactId, message));
-					db.receiveMessage(txn, contactId, message);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -172,13 +161,8 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				Transaction txn = db.startTransaction(false);
+				db.transaction(false,
-				try {
+						txn -> db.receiveOffer(txn, contactId, offer));
-					db.receiveOffer(txn, contactId, offer);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -198,13 +182,8 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				Transaction txn = db.startTransaction(false);
+				db.transaction(false,
-				try {
+						txn -> db.receiveRequest(txn, contactId, request));
-					db.receiveRequest(txn, contactId, request);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();

bramble-core/src/main/java/org/briarproject/bramble/sync/SimplexOutgoingSession.java

@@ -1,11 +1,11 @@
 package org.briarproject.bramble.sync;
 
+import org.briarproject.bramble.api.Maybe;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -47,7 +47,8 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(SimplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {
+	};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -128,18 +129,13 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		public void run() {
 			if (interrupted) return;
 			try {
-				Ack a;
+				Maybe<Ack> a = db.transactionWithResult(false,
-				Transaction txn = db.startTransaction(false);
+						txn -> new Maybe<>(db.generateAck(txn, contactId,
-				try {
+								MAX_MESSAGE_IDS)));
-					a = db.generateAck(txn, contactId, MAX_MESSAGE_IDS);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated ack: " + (a != null));
+					LOG.info("Generated ack: " + a.isPresent());
-				if (a == null) decrementOutstandingQueries();
+				if (a.isPresent()) writerTasks.add(new WriteAck(a.get()));
-				else writerTasks.add(new WriteAck(a));
+				else decrementOutstandingQueries();
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -172,19 +168,13 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		public void run() {
 			if (interrupted) return;
 			try {
-				Collection<Message> b;
+				Maybe<Collection<Message>> b = db.transactionWithResult(false,
-				Transaction txn = db.startTransaction(false);
+						txn -> new Maybe<>(db.generateBatch(txn, contactId,
-				try {
+								MAX_RECORD_PAYLOAD_BYTES, maxLatency)));
-					b = db.generateBatch(txn, contactId,
-							MAX_RECORD_PAYLOAD_BYTES, maxLatency);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 				if (LOG.isLoggable(INFO))
-					LOG.info("Generated batch: " + (b != null));
+					LOG.info("Generated batch: " + b.isPresent());
-				if (b == null) decrementOutstandingQueries();
+				if (b.isPresent()) writerTasks.add(new WriteBatch(b.get()));
-				else writerTasks.add(new WriteBatch(b));
+				else decrementOutstandingQueries();
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();

bramble-core/src/main/java/org/briarproject/bramble/sync/ValidationManagerImpl.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.sync;
 
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
@@ -97,14 +98,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void validateOutstandingMessages() {
 		try {
-			Queue<MessageId> unvalidated = new LinkedList<>();
+			Queue<MessageId> unvalidated = new LinkedList<>(
-			Transaction txn = db.startTransaction(true);
+					db.transactionWithResult(true, db::getMessagesToValidate));
-			try {
-				unvalidated.addAll(db.getMessagesToValidate(txn));
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 			validateNextMessageAsync(unvalidated);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -119,18 +114,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void validateNextMessage(Queue<MessageId> unvalidated) {
 		try {
-			Message m;
+			Pair<Message, Group> mg = db.transactionWithResult(true, txn -> {
-			Group g;
-			Transaction txn = db.startTransaction(true);
-			try {
 				MessageId id = unvalidated.poll();
-				m = db.getMessage(txn, id);
+				if (id == null) throw new AssertionError();
-				g = db.getGroup(txn, m.getGroupId());
+				Message m = db.getMessage(txn, id);
-				db.commitTransaction(txn);
+				Group g = db.getGroup(txn, m.getGroupId());
-			} finally {
+				return new Pair<>(m, g);
-				db.endTransaction(txn);
+			});
-			}
+			validateMessageAsync(mg.getFirst(), mg.getSecond());
-			validateMessageAsync(m, g);
 			validateNextMessageAsync(unvalidated);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before validation");
@@ -150,14 +141,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void deliverOutstandingMessages() {
 		try {
-			Queue<MessageId> pending = new LinkedList<>();
+			Queue<MessageId> pending = new LinkedList<>(
-			Transaction txn = db.startTransaction(true);
+					db.transactionWithResult(true, db::getPendingMessages));
-			try {
-				pending.addAll(db.getPendingMessages(txn));
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 			deliverNextPendingMessageAsync(pending);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -172,12 +157,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void deliverNextPendingMessage(Queue<MessageId> pending) {
 		try {
-			boolean anyInvalid = false, allDelivered = true;
+			Queue<MessageId> toShare = new LinkedList<>();
-			Queue<MessageId> toShare = null;
+			Queue<MessageId> invalidate = new LinkedList<>();
-			Queue<MessageId> invalidate = null;
+			db.transaction(false, txn -> {
-			Transaction txn = db.startTransaction(false);
+				boolean anyInvalid = false, allDelivered = true;
-			try {
 				MessageId id = pending.poll();
+				if (id == null) throw new AssertionError();
 				// Check if message is still pending
 				if (db.getMessageState(txn, id) == PENDING) {
 					// Check if dependencies are valid and delivered
@@ -189,7 +174,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 					}
 					if (anyInvalid) {
 						invalidateMessage(txn, id);
-						invalidate = getDependentsToInvalidate(txn, id);
+						addDependentsToInvalidate(txn, id, invalidate);
 					} else if (allDelivered) {
 						Message m = db.getMessage(txn, id);
 						Group g = db.getGroup(txn, m.getGroupId());
@@ -200,22 +185,19 @@ class ValidationManagerImpl implements ValidationManager, Service,
 						DeliveryResult result =
 								deliverMessage(txn, m, c, majorVersion, meta);
 						if (result.valid) {
-							pending.addAll(getPendingDependents(txn, id));
+							addPendingDependents(txn, id, pending);
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare = new LinkedList<>(states.keySet());
+								toShare.addAll(states.keySet());
 							}
 						} else {
-							invalidate = getDependentsToInvalidate(txn, id);
+							addDependentsToInvalidate(txn, id, invalidate);
 						}
 					}
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
+			if (!invalidate.isEmpty()) invalidateNextMessageAsync(invalidate);
-				db.endTransaction(txn);
+			if (!toShare.isEmpty()) shareNextMessageAsync(toShare);
-			}
-			if (invalidate != null) invalidateNextMessageAsync(invalidate);
-			if (toShare != null) shareNextMessageAsync(toShare);
 			deliverNextPendingMessageAsync(pending);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before delivery");
@@ -264,12 +246,11 @@ class ValidationManagerImpl implements ValidationManager, Service,
 			MessageContext context) {
 		try {
 			MessageId id = m.getId();
-			boolean anyInvalid = false, allDelivered = true;
+			Queue<MessageId> invalidate = new LinkedList<>();
-			Queue<MessageId> invalidate = null;
+			Queue<MessageId> pending = new LinkedList<>();
-			Queue<MessageId> pending = null;
+			Queue<MessageId> toShare = new LinkedList<>();
-			Queue<MessageId> toShare = null;
+			db.transaction(false, txn -> {
-			Transaction txn = db.startTransaction(false);
+				boolean anyInvalid = false, allDelivered = true;
-			try {
 				// Check if message has any dependencies
 				Collection<MessageId> dependencies = context.getDependencies();
 				if (!dependencies.isEmpty()) {
@@ -285,7 +266,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 				if (anyInvalid) {
 					if (db.getMessageState(txn, id) != INVALID) {
 						invalidateMessage(txn, id);
-						invalidate = getDependentsToInvalidate(txn, id);
+						addDependentsToInvalidate(txn, id, invalidate);
 					}
 				} else {
 					Metadata meta = context.getMetadata();
@@ -294,25 +275,22 @@ class ValidationManagerImpl implements ValidationManager, Service,
 						DeliveryResult result =
 								deliverMessage(txn, m, c, majorVersion, meta);
 						if (result.valid) {
-							pending = getPendingDependents(txn, id);
+							addPendingDependents(txn, id, pending);
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare = new LinkedList<>(dependencies);
+								toShare.addAll(dependencies);
 							}
 						} else {
-							invalidate = getDependentsToInvalidate(txn, id);
+							addDependentsToInvalidate(txn, id, invalidate);
 						}
 					} else {
 						db.setMessageState(txn, id, PENDING);
 					}
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
+			if (!invalidate.isEmpty()) invalidateNextMessageAsync(invalidate);
-				db.endTransaction(txn);
+			if (!pending.isEmpty()) deliverNextPendingMessageAsync(pending);
-			}
+			if (!toShare.isEmpty()) shareNextMessageAsync(toShare);
-			if (invalidate != null) invalidateNextMessageAsync(invalidate);
-			if (pending != null) deliverNextPendingMessageAsync(pending);
-			if (toShare != null) shareNextMessageAsync(toShare);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed during validation");
 		} catch (NoSuchGroupException e) {
@@ -342,14 +320,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	}
 
 	@DatabaseExecutor
-	private Queue<MessageId> getPendingDependents(Transaction txn, MessageId m)
+	private void addPendingDependents(Transaction txn, MessageId m,
-			throws DbException {
+			Queue<MessageId> pending) throws DbException {
-		Queue<MessageId> pending = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() == PENDING) pending.add(e.getKey());
 		}
-		return pending;
 	}
 
 	private void shareOutstandingMessagesAsync() {
@@ -359,14 +335,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void shareOutstandingMessages() {
 		try {
-			Queue<MessageId> toShare = new LinkedList<>();
+			Queue<MessageId> toShare = new LinkedList<>(
-			Transaction txn = db.startTransaction(true);
+					db.transactionWithResult(true, db::getMessagesToShare));
-			try {
-				toShare.addAll(db.getMessagesToShare(txn));
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 			shareNextMessageAsync(toShare);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -387,15 +357,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void shareNextMessage(Queue<MessageId> toShare) {
 		try {
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				MessageId id = toShare.poll();
+				if (id == null) throw new AssertionError();
 				db.setMessageShared(txn, id);
 				toShare.addAll(db.getMessageDependencies(txn, id).keySet());
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 			shareNextMessageAsync(toShare);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before sharing");
@@ -416,17 +383,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void invalidateNextMessage(Queue<MessageId> invalidate) {
 		try {
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				MessageId id = invalidate.poll();
+				if (id == null) throw new AssertionError();
 				if (db.getMessageState(txn, id) != INVALID) {
 					invalidateMessage(txn, id);
-					invalidate.addAll(getDependentsToInvalidate(txn, id));
+					addDependentsToInvalidate(txn, id, invalidate);
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 			invalidateNextMessageAsync(invalidate);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before invalidation");
@@ -445,14 +409,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	}
 
 	@DatabaseExecutor
-	private Queue<MessageId> getDependentsToInvalidate(Transaction txn,
+	private void addDependentsToInvalidate(Transaction txn,
-			MessageId m) throws DbException {
+			MessageId m, Queue<MessageId> invalidate) throws DbException {
-		Queue<MessageId> invalidate = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() != INVALID) invalidate.add(e.getKey());
 		}
-		return invalidate;
 	}
 
 	@Override
@@ -472,14 +434,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void loadGroupAndValidate(Message m) {
 		try {
-			Group g;
+			Group g = db.transactionWithResult(true,
-			Transaction txn = db.startTransaction(true);
+					txn -> db.getGroup(txn, m.getGroupId()));
-			try {
-				g = db.getGroup(txn, m.getGroupId());
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 			validateMessageAsync(m, g);
 		} catch (NoSuchGroupException e) {
 			LOG.info("Group removed before validation");

bramble-core/src/main/java/org/briarproject/bramble/transport/KeyManagerImpl.java

@@ -72,8 +72,7 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		for (DuplexPluginFactory f : pluginConfig.getDuplexFactories())
 			transports.put(f.getId(), f.getMaxLatency());
 		try {
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				for (Contact c : db.getContacts(txn))
 					if (c.isActive()) activeContacts.put(c.getId(), true);
 				for (Entry<TransportId, Integer> e : transports.entrySet())
@@ -85,10 +84,7 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 					managers.put(e.getKey(), m);
 					m.start(txn);
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}
@@ -141,15 +137,8 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
 			return null;
 		}
-		StreamContext ctx;
+		return db.transactionWithResult(false,
-		Transaction txn = db.startTransaction(false);
+				txn -> m.getStreamContext(txn, c));
-		try {
-			ctx = m.getStreamContext(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return ctx;
 	}
 
 	@Override
@@ -160,15 +149,8 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
 			return null;
 		}
-		StreamContext ctx;
+		return db.transactionWithResult(false,
-		Transaction txn = db.startTransaction(false);
+				txn -> m.getStreamContext(txn, tag));
-		try {
-			ctx = m.getStreamContext(txn, tag);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return ctx;
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java

@@ -162,13 +162,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private void rotateKeys() {
 		dbExecutor.execute(() -> {
 			try {
-				Transaction txn = db.startTransaction(false);
+				db.transaction(false, this::rotateKeys);
-				try {
-					rotateKeys(txn);
-					db.commitTransaction(txn);
-				} finally {
-					db.endTransaction(txn);
-				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningManagerImpl.java

@@ -123,16 +123,12 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 		List<ClientVersion> versions = new ArrayList<>(clients);
 		Collections.sort(versions);
 		try {
-			Transaction txn = db.startTransaction(false);
+			db.transaction(false, txn -> {
-			try {
 				if (updateClientVersions(txn, versions)) {
 					for (Contact c : db.getContacts(txn))
 						clientVersionsUpdated(txn, c, versions);
 				}
-				db.commitTransaction(txn);
+			});
-			} finally {
-				db.endTransaction(txn);
-			}
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}

bramble-core/src/test/java/org/briarproject/bramble/client/ClientHelperImplTest.java

@@ -22,6 +22,7 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
 import org.jmock.Mockery;
@@ -85,14 +86,11 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		boolean shared = new Random().nextBoolean();
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).addLocalMessage(txn, message, metadata, shared);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.addLocalMessage(message, dictionary, shared);
@@ -116,13 +114,10 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		Transaction txn = new Transaction(null, true);
 
 		expectToList(true);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessage(txn, messageId);
 			will(returnValue(message));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.getMessageAsList(messageId);
@@ -133,15 +128,12 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testGetGroupMetadataAsDictionary() throws Exception {
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroupMetadata(txn, groupId);
 			will(returnValue(metadata));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(dictionary,
@@ -153,15 +145,12 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testGetMessageMetadataAsDictionary() throws Exception {
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessageMetadata(txn, messageId);
 			will(returnValue(metadata));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(dictionary,
@@ -175,15 +164,12 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		map.put(messageId, dictionary);
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessageMetadata(txn, groupId);
 			will(returnValue(Collections.singletonMap(messageId, metadata)));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(map, clientHelper.getMessageMetadataAsDictionary(groupId));
@@ -200,17 +186,14 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		queryMetadata.put("query", getRandomBytes(42));
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(query);
 			will(returnValue(queryMetadata));
 			oneOf(db).getMessageMetadata(txn, groupId, queryMetadata);
 			will(returnValue(Collections.singletonMap(messageId, metadata)));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(map,
@@ -222,14 +205,11 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testMergeGroupMetadata() throws Exception {
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).mergeGroupMetadata(txn, groupId, metadata);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.mergeGroupMetadata(groupId, dictionary);
@@ -240,14 +220,11 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testMergeMessageMetadata() throws Exception {
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).mergeMessageMetadata(txn, messageId, metadata);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.mergeMessageMetadata(messageId, dictionary);

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactManagerImplTest.java

@@ -69,17 +69,14 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		boolean alice = new Random().nextBoolean();
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).addContact(txn, remote, local, verified, active);
 			will(returnValue(contactId));
 			oneOf(keyManager).addContact(txn, contactId, master, timestamp,
 					alice, active);
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contactId, contactManager.addContact(remote, local,
@@ -89,13 +86,10 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testGetContact() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contact, contactManager.getContact(contactId));
@@ -105,13 +99,10 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	public void testGetContactByAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
 			will(returnValue(contacts));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contact, contactManager.getContact(remote.getId(), local));
@@ -120,12 +111,10 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
 			will(returnValue(emptyList()));
-			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.getContact(remote.getId(), local);
@@ -135,31 +124,26 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	public void testGetContactByUnknownLocalAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
 			will(returnValue(contacts));
-			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.getContact(remote.getId(), new AuthorId(getRandomId()));
 	}
 
 	@Test
-	public void testActiveContacts() throws Exception {
+	public void testGetActiveContacts() throws Exception {
 		Collection<Contact> activeContacts = Collections.singletonList(contact);
 		Collection<Contact> contacts = new ArrayList<>(activeContacts);
 		contacts.add(new Contact(new ContactId(3), remote, local, alias, true,
 				false));
 		Transaction txn = new Transaction(null, true);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(activeContacts, contactManager.getActiveContacts());
@@ -168,14 +152,11 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testRemoveContact() throws Exception {
 		Transaction txn = new Transaction(null, false);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
 			oneOf(db).removeContact(txn, contactId);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.removeContact(contactId);
@@ -195,7 +176,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	public void testSetContactAlias() throws Exception {
 		Transaction txn = new Transaction(null, false);
 		context.checking(new DbExpectations() {{
-			oneOf(db).transaction(with(equal(false)), withDbRunnable(txn));
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
 			oneOf(db).setContactAlias(txn, contactId, alias);
 		}});
 
@@ -212,28 +193,24 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testContactExists() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).containsContact(txn, remote.getId(), local);
 			will(returnValue(true));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertTrue(contactManager.contactExists(remote.getId(), local));
 	}
 
 	@Test
-	public void testGetAuthorStatus() throws Exception {
+	public void testGetAuthorInfo() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		Collection<Contact> contacts = singletonList(
 				new Contact(new ContactId(1), remote, localAuthor.getId(),
 						alias, false, true));
 
 		context.checking(new DbExpectations() {{
-			oneOf(db).transactionWithResult(with(equal(true)),
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-					withDbCallable(txn));
 			oneOf(identityManager).getLocalAuthor(txn);
 			will(returnValue(localAuthor));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
@@ -246,7 +223,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testGetAuthorStatusTransaction() throws DbException {
+	public void testGetAuthorInfoTransaction() throws DbException {
 		Transaction txn = new Transaction(null, true);
 
 		// check unknown author
@@ -265,7 +242,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		Collection<Contact> contacts = singletonList(
 				new Contact(new ContactId(1), remote, localAuthor.getId(),
 						alias, false, true));
-		checkAuthorStatusContext(txn, remote.getId(), contacts);
+		checkAuthorInfoContext(txn, remote.getId(), contacts);
 		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
 		assertEquals(UNVERIFIED, authorInfo.getStatus());
 		assertEquals(alias, contact.getAlias());
@@ -273,7 +250,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		// check verified contact
 		contacts = singletonList(new Contact(new ContactId(1), remote,
 				localAuthor.getId(), alias, true, true));
-		checkAuthorStatusContext(txn, remote.getId(), contacts);
+		checkAuthorInfoContext(txn, remote.getId(), contacts);
 		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
 		assertEquals(VERIFIED, authorInfo.getStatus());
 		assertEquals(alias, contact.getAlias());
@@ -289,7 +266,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		assertNull(authorInfo.getAlias());
 	}
 
-	private void checkAuthorStatusContext(Transaction txn, AuthorId authorId,
+	private void checkAuthorInfoContext(Transaction txn, AuthorId authorId,
 			Collection<Contact> contacts) throws DbException {
 		context.checking(new Expectations() {{
 			oneOf(identityManager).getLocalAuthor(txn);

bramble-core/src/test/java/org/briarproject/bramble/identity/IdentityManagerImplTest.java

@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.junit.Before;
 import org.junit.Test;
@@ -64,13 +65,10 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testRegisterAndStoreLocalAuthor() throws DbException {
+	public void testRegisterAndStoreLocalAuthor() throws Exception {
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(db).addLocalAuthor(txn, localAuthor);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		identityManager.registerLocalAuthor(localAuthor);
@@ -79,14 +77,11 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testGetLocalAuthor() throws DbException {
+	public void testGetLocalAuthor() throws Exception {
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getLocalAuthors(txn);
 			will(returnValue(localAuthors));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 		assertEquals(localAuthor, identityManager.getLocalAuthor());
 	}

bramble-core/src/test/java/org/briarproject/bramble/properties/TransportPropertyManagerImplTest.java

@@ -21,16 +21,18 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.junit.Test;
 
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import static java.util.Arrays.asList;
 import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
 import static org.briarproject.bramble.api.properties.TransportPropertyManager.CLIENT_ID;
 import static org.briarproject.bramble.api.properties.TransportPropertyManager.MAJOR_VERSION;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
@@ -351,14 +353,11 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry("local", true)
 		));
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
 			will(returnValue(messageMetadata));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -386,9 +385,8 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		));
 		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
 			will(returnValue(messageMetadata));
@@ -397,8 +395,6 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).parseAndValidateTransportProperties(
 					fooPropertiesDict);
 			will(returnValue(fooProperties));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -413,8 +409,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Contact contact1 = getContact(false);
 		Contact contact2 = getContact(true);
 		Contact contact3 = getContact(true);
-		List<Contact> contacts =
+		List<Contact> contacts = asList(contact1, contact2, contact3);
-				Arrays.asList(contact1, contact2, contact3);
 		Group contactGroup2 = getGroup(CLIENT_ID, MAJOR_VERSION);
 		Group contactGroup3 = getGroup(CLIENT_ID, MAJOR_VERSION);
 		Map<MessageId, BdfDictionary> messageMetadata3 =
@@ -442,9 +437,8 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		));
 		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
 			// First contact: skipped because not active
@@ -467,8 +461,6 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).parseAndValidateTransportProperties(
 					fooPropertiesDict);
 			will(returnValue(fooProperties));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -485,17 +477,16 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			throws Exception {
 		Transaction txn = new Transaction(null, false);
 		MessageId updateId = new MessageId(getRandomId());
-		Map<MessageId, BdfDictionary> messageMetadata =
+		Map<MessageId, BdfDictionary> messageMetadata = singletonMap(updateId,
-				Collections.singletonMap(updateId, BdfDictionary.of(
+				BdfDictionary.of(
 						new BdfEntry("transportId", "foo"),
 						new BdfEntry("version", 1),
 						new BdfEntry("local", true)
 				));
 		BdfList update = BdfList.of("foo", 1, fooPropertiesDict);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// Merge the new properties with the existing properties
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
@@ -506,8 +497,6 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 					fooPropertiesDict);
 			will(returnValue(fooProperties));
 			// Properties are unchanged so we're done
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -520,9 +509,8 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Contact contact = getContact(true);
 		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// There are no existing properties to merge with
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
@@ -541,8 +529,6 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(Collections.emptyMap()));
 			expectStoreMessage(txn, contactGroup.getId(), "foo",
 					fooPropertiesDict, 1, true, true);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -561,10 +547,10 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		);
 		MessageId localGroupUpdateId = new MessageId(getRandomId());
 		Map<MessageId, BdfDictionary> localGroupMessageMetadata =
-				Collections.singletonMap(localGroupUpdateId, oldMetadata);
+				singletonMap(localGroupUpdateId, oldMetadata);
 		MessageId contactGroupUpdateId = new MessageId(getRandomId());
 		Map<MessageId, BdfDictionary> contactGroupMessageMetadata =
-				Collections.singletonMap(contactGroupUpdateId, oldMetadata);
+				singletonMap(contactGroupUpdateId, oldMetadata);
 		TransportProperties oldProperties = new TransportProperties();
 		oldProperties.put("fooKey1", "oldFooValue1");
 		BdfDictionary oldPropertiesDict = BdfDictionary.of(
@@ -572,9 +558,8 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		);
 		BdfList oldUpdate = BdfList.of("foo", 1, oldPropertiesDict);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// Merge the new properties with the existing properties
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
@@ -602,8 +587,6 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 					fooPropertiesDict, 2, true, true);
 			// Delete the previous update
 			oneOf(db).removeMessage(txn, contactGroupUpdateId);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();

bramble-core/src/test/java/org/briarproject/bramble/sync/SimplexOutgoingSessionTest.java

@@ -11,8 +11,8 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
 import org.briarproject.bramble.api.transport.StreamWriter;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.briarproject.bramble.test.ImmediateExecutor;
-import org.jmock.Expectations;
 import org.junit.Test;
 
 import java.util.concurrent.Executor;
@@ -45,24 +45,20 @@ public class SimplexOutgoingSessionTest extends BrambleMockTestCase {
 		Transaction noAckTxn = new Transaction(null, false);
 		Transaction noMsgTxn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Add listener
 			oneOf(eventBus).addListener(session);
 			// No acks to send
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(noAckTxn));
+					withDbCallable(noAckTxn));
 			oneOf(db).generateAck(noAckTxn, contactId, MAX_MESSAGE_IDS);
 			will(returnValue(null));
-			oneOf(db).commitTransaction(noAckTxn);
-			oneOf(db).endTransaction(noAckTxn);
 			// No messages to send
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(noMsgTxn));
+					withDbCallable(noMsgTxn));
 			oneOf(db).generateBatch(with(noMsgTxn), with(contactId),
 					with(any(int.class)), with(MAX_LATENCY));
 			will(returnValue(null));
-			oneOf(db).commitTransaction(noMsgTxn);
-			oneOf(db).endTransaction(noMsgTxn);
 			// Send the end of stream marker
 			oneOf(streamWriter).sendEndOfStream();
 			// Remove listener
@@ -83,41 +79,33 @@ public class SimplexOutgoingSessionTest extends BrambleMockTestCase {
 		Transaction msgTxn = new Transaction(null, false);
 		Transaction noMsgTxn = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Add listener
 			oneOf(eventBus).addListener(session);
 			// One ack to send
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(ackTxn));
+					withDbCallable(ackTxn));
 			oneOf(db).generateAck(ackTxn, contactId, MAX_MESSAGE_IDS);
 			will(returnValue(ack));
-			oneOf(db).commitTransaction(ackTxn);
-			oneOf(db).endTransaction(ackTxn);
 			oneOf(recordWriter).writeAck(ack);
 			// One message to send
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(msgTxn));
+					withDbCallable(msgTxn));
 			oneOf(db).generateBatch(with(msgTxn), with(contactId),
 					with(any(int.class)), with(MAX_LATENCY));
 			will(returnValue(singletonList(message)));
-			oneOf(db).commitTransaction(msgTxn);
-			oneOf(db).endTransaction(msgTxn);
 			oneOf(recordWriter).writeMessage(message);
 			// No more acks
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(noAckTxn));
+					withDbCallable(noAckTxn));
 			oneOf(db).generateAck(noAckTxn, contactId, MAX_MESSAGE_IDS);
 			will(returnValue(null));
-			oneOf(db).commitTransaction(noAckTxn);
-			oneOf(db).endTransaction(noAckTxn);
 			// No more messages
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false),
-			will(returnValue(noMsgTxn));
+					withDbCallable(noMsgTxn));
 			oneOf(db).generateBatch(with(noMsgTxn), with(contactId),
 					with(any(int.class)), with(MAX_LATENCY));
 			will(returnValue(null));
-			oneOf(db).commitTransaction(noMsgTxn);
-			oneOf(db).endTransaction(noMsgTxn);
 			// Send the end of stream marker
 			oneOf(streamWriter).sendEndOfStream();
 			// Remove listener

bramble-core/src/test/java/org/briarproject/bramble/sync/ValidationManagerImplTest.java

@@ -18,16 +18,16 @@ import org.briarproject.bramble.api.sync.ValidationManager.MessageValidator;
 import org.briarproject.bramble.api.sync.ValidationManager.State;
 import org.briarproject.bramble.api.sync.event.MessageAddedEvent;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.briarproject.bramble.test.ImmediateExecutor;
-import org.jmock.Expectations;
 import org.junit.Before;
 import org.junit.Test;
 
-import java.util.Arrays;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
 
+import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
@@ -83,28 +83,19 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn1 = new Transaction(null, true);
 		Transaction txn2 = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// validateOutstandingMessages()
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// deliverOutstandingMessages()
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getPendingMessages(txn1);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// shareOutstandingMessages()
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessagesToShare(txn2);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 		}});
 
 		vm.startService();
@@ -121,29 +112,22 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn5 = new Transaction(null, true);
 		Transaction txn6 = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Get messages to validate
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
-			will(returnValue(Arrays.asList(messageId, messageId1)));
+			will(returnValue(asList(messageId, messageId1)));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Load the first raw message and group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getMessage(txn1, messageId);
 			will(returnValue(message));
 			oneOf(db).getGroup(txn1, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Validate the first message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResult));
 			// Store the validation result for the first message
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).mergeMessageMetadata(txn2, messageId, metadata);
 			// Deliver the first message
 			oneOf(hook).incomingMessage(txn2, message, metadata);
@@ -152,23 +136,17 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn2, messageId);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Load the second raw message and group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessage(txn3, messageId1);
 			will(returnValue(message1));
 			oneOf(db).getGroup(txn3, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Validate the second message: invalid
 			oneOf(validator).validateMessage(message1, group);
 			will(throwException(new InvalidMessageException()));
 			// Store the validation result for the second message
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getMessageState(txn4, messageId1);
 			will(returnValue(UNKNOWN));
 			oneOf(db).setMessageState(txn4, messageId1, INVALID);
@@ -177,22 +155,14 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Recursively invalidate any dependents
 			oneOf(db).getMessageDependents(txn4, messageId1);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 			// Get pending messages to deliver
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn5));
-			will(returnValue(txn5));
 			oneOf(db).getPendingMessages(txn5);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn5);
-			oneOf(db).endTransaction(txn5);
 			// Get messages to share
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn6));
-			will(returnValue(txn6));
 			oneOf(db).getMessagesToShare(txn6);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn6);
-			oneOf(db).endTransaction(txn6);
 		}});
 
 		vm.startService();
@@ -206,24 +176,17 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn3 = new Transaction(null, false);
 		Transaction txn4 = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Get messages to validate
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Get pending messages to deliver
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getPendingMessages(txn1);
 			will(returnValue(singletonList(messageId)));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Check whether the message is ready to deliver
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessageState(txn2, messageId);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn2, messageId);
@@ -242,11 +205,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn2, messageId);
 			will(returnValue(singletonMap(messageId2, PENDING)));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Check whether the dependent is ready to deliver
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessageState(txn3, messageId2);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn3, messageId2);
@@ -265,16 +225,11 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn3, messageId2);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 
 			// Get messages to share
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getMessagesToShare(txn4);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 		}});
 
 		vm.startService();
@@ -288,45 +243,30 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn3 = new Transaction(null, false);
 		Transaction txn4 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// No messages to validate
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// No pending messages to deliver
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getPendingMessages(txn1);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 
 			// Get messages to share
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessagesToShare(txn2);
 			will(returnValue(singletonList(messageId)));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Share message and get dependencies
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).setMessageShared(txn3, messageId);
 			oneOf(db).getMessageDependencies(txn3, messageId);
 			will(returnValue(singletonMap(messageId2, DELIVERED)));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Share dependency
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).setMessageShared(txn4, messageId2);
 			oneOf(db).getMessageDependencies(txn4, messageId2);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 		}});
 
 		vm.startService();
@@ -338,20 +278,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn1 = new Transaction(null, false);
 		Transaction txn2 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResultWithDependencies));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).addMessageDependencies(txn1, message,
 					validResultWithDependencies.getDependencies());
 			oneOf(db).getMessageDependencies(txn1, messageId);
@@ -366,16 +302,11 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(emptyMap()));
 			// Share message
 			oneOf(db).setMessageShared(txn1, messageId);
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Share dependencies
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).setMessageShared(txn2, messageId1);
 			oneOf(db).getMessageDependencies(txn2, messageId1);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -391,36 +322,26 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn4 = new Transaction(null, true);
 		Transaction txn5 = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Get messages to validate
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
-			will(returnValue(Arrays.asList(messageId, messageId1)));
+			will(returnValue(asList(messageId, messageId1)));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Load the first raw message - *gasp* it's gone!
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getMessage(txn1, messageId);
 			will(throwException(new NoSuchMessageException()));
-			never(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Load the second raw message and group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessage(txn2, messageId1);
 			will(returnValue(message1));
 			oneOf(db).getGroup(txn2, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Validate the second message: invalid
 			oneOf(validator).validateMessage(message1, group);
 			will(throwException(new InvalidMessageException()));
 			// Invalidate the second message
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessageState(txn3, messageId1);
 			will(returnValue(UNKNOWN));
 			oneOf(db).setMessageState(txn3, messageId1, INVALID);
@@ -429,22 +350,14 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Recursively invalidate dependents
 			oneOf(db).getMessageDependents(txn3, messageId1);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Get pending messages to deliver
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getPendingMessages(txn4);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 			// Get messages to share
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn5));
-			will(returnValue(txn5));
 			oneOf(db).getMessagesToShare(txn5);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn5);
-			oneOf(db).endTransaction(txn5);
 		}});
 
 		vm.startService();
@@ -460,39 +373,29 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn4 = new Transaction(null, true);
 		Transaction txn5 = new Transaction(null, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Get messages to validate
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getMessagesToValidate(txn);
-			will(returnValue(Arrays.asList(messageId, messageId1)));
+			will(returnValue(asList(messageId, messageId1)));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Load the first raw message
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getMessage(txn1, messageId);
 			will(returnValue(message));
 			// Load the group - *gasp* it's gone!
 			oneOf(db).getGroup(txn1, groupId);
 			will(throwException(new NoSuchGroupException()));
-			never(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Load the second raw message and group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessage(txn2, messageId1);
 			will(returnValue(message1));
 			oneOf(db).getGroup(txn2, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Validate the second message: invalid
 			oneOf(validator).validateMessage(message1, group);
 			will(throwException(new InvalidMessageException()));
 			// Store the validation result for the second message
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessageState(txn3, messageId1);
 			will(returnValue(UNKNOWN));
 			oneOf(db).setMessageState(txn3, messageId1, INVALID);
@@ -501,22 +404,14 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Recursively invalidate dependents
 			oneOf(db).getMessageDependents(txn3, messageId1);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Get pending messages to deliver
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getPendingMessages(txn4);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 			// Get messages to share
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn5));
-			will(returnValue(txn5));
 			oneOf(db).getMessagesToShare(txn5);
 			will(returnValue(emptyList()));
-			oneOf(db).commitTransaction(txn5);
-			oneOf(db).endTransaction(txn5);
 		}});
 
 		vm.startService();
@@ -527,20 +422,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn = new Transaction(null, true);
 		Transaction txn1 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResult));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).mergeMessageMetadata(txn1, messageId, metadata);
 			// Deliver the message
 			oneOf(hook).incomingMessage(txn1, message, metadata);
@@ -549,8 +440,6 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -567,28 +456,22 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn = new Transaction(null, true);
 		Transaction txn1 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResultWithDependencies));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).addMessageDependencies(txn1, message,
 					validResultWithDependencies.getDependencies());
 			oneOf(db).getMessageDependencies(txn1, messageId);
 			will(returnValue(singletonMap(messageId1, UNKNOWN)));
 			oneOf(db).mergeMessageMetadata(txn1, messageId, metadata);
 			oneOf(db).setMessageState(txn1, messageId, PENDING);
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -600,20 +483,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn = new Transaction(null, true);
 		Transaction txn1 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResultWithDependencies));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).addMessageDependencies(txn1, message,
 					validResultWithDependencies.getDependencies());
 			oneOf(db).getMessageDependencies(txn1, messageId);
@@ -626,8 +505,6 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -640,20 +517,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn1 = new Transaction(null, false);
 		Transaction txn2 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResultWithDependencies));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).addMessageDependencies(txn1, message,
 					validResultWithDependencies.getDependencies());
 			// Check for invalid dependencies
@@ -668,11 +541,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Recursively invalidate dependents
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(singletonMap(messageId2, UNKNOWN)));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Invalidate dependent in a new transaction
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessageState(txn2, messageId2);
 			will(returnValue(UNKNOWN));
 			oneOf(db).setMessageState(txn2, messageId2, INVALID);
@@ -680,8 +550,6 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).deleteMessageMetadata(txn2, messageId2);
 			oneOf(db).getMessageDependents(txn2, messageId2);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -702,20 +570,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn5 = new Transaction(null, false);
 		Transaction txn6 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: invalid
 			oneOf(validator).validateMessage(message, group);
 			will(throwException(new InvalidMessageException()));
 			// Invalidate the message
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).getMessageState(txn1, messageId);
 			will(returnValue(UNKNOWN));
 			oneOf(db).setMessageState(txn1, messageId, INVALID);
@@ -724,11 +588,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// The message has two dependents: 1 and 2
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(twoDependents));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Invalidate message 1
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessageState(txn2, messageId1);
 			will(returnValue(PENDING));
 			oneOf(db).setMessageState(txn2, messageId1, INVALID);
@@ -737,11 +598,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 1 has one dependent: 3
 			oneOf(db).getMessageDependents(txn2, messageId1);
 			will(returnValue(singletonMap(messageId3, PENDING)));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Invalidate message 2
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessageState(txn3, messageId2);
 			will(returnValue(PENDING));
 			oneOf(db).setMessageState(txn3, messageId2, INVALID);
@@ -750,11 +608,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 2 has one dependent: 3 (same dependent as 1)
 			oneOf(db).getMessageDependents(txn3, messageId2);
 			will(returnValue(singletonMap(messageId3, PENDING)));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Invalidate message 3 (via 1)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getMessageState(txn4, messageId3);
 			will(returnValue(PENDING));
 			oneOf(db).setMessageState(txn4, messageId3, INVALID);
@@ -763,18 +618,12 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 3 has one dependent: 4
 			oneOf(db).getMessageDependents(txn4, messageId3);
 			will(returnValue(singletonMap(messageId4, PENDING)));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 			// Invalidate message 3 (again, via 2)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn5));
-			will(returnValue(txn5));
 			oneOf(db).getMessageState(txn5, messageId3);
 			will(returnValue(INVALID)); // Already invalidated
-			oneOf(db).commitTransaction(txn5);
-			oneOf(db).endTransaction(txn5);
 			// Invalidate message 4 (via 1 and 3)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn6));
-			will(returnValue(txn6));
 			oneOf(db).getMessageState(txn6, messageId4);
 			will(returnValue(PENDING));
 			oneOf(db).setMessageState(txn6, messageId4, INVALID);
@@ -783,8 +632,6 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 4 has no dependents
 			oneOf(db).getMessageDependents(txn6, messageId4);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn6);
-			oneOf(db).endTransaction(txn6);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -810,20 +657,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn5 = new Transaction(null, false);
 		Transaction txn6 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResult));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).mergeMessageMetadata(txn1, messageId, metadata);
 			// Deliver the message
 			oneOf(hook).incomingMessage(txn1, message, metadata);
@@ -832,11 +675,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// The message has two pending dependents: 1 and 2
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(twoDependents));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Check whether message 1 is ready to be delivered
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessageState(txn2, messageId1);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn2, messageId1);
@@ -855,11 +695,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 1 has one pending dependent: 3
 			oneOf(db).getMessageDependents(txn2, messageId1);
 			will(returnValue(singletonMap(messageId3, PENDING)));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 			// Check whether message 2 is ready to be delivered
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn3));
-			will(returnValue(txn3));
 			oneOf(db).getMessageState(txn3, messageId2);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn3, messageId2);
@@ -878,11 +715,8 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 2 has one pending dependent: 3 (same dependent as 1)
 			oneOf(db).getMessageDependents(txn3, messageId2);
 			will(returnValue(singletonMap(messageId3, PENDING)));
-			oneOf(db).commitTransaction(txn3);
-			oneOf(db).endTransaction(txn3);
 			// Check whether message 3 is ready to be delivered (via 1)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn4));
-			will(returnValue(txn4));
 			oneOf(db).getMessageState(txn4, messageId3);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn4, messageId3);
@@ -900,18 +734,12 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 3 has one pending dependent: 4
 			oneOf(db).getMessageDependents(txn4, messageId3);
 			will(returnValue(singletonMap(messageId4, PENDING)));
-			oneOf(db).commitTransaction(txn4);
-			oneOf(db).endTransaction(txn4);
 			// Check whether message 3 is ready to be delivered (again, via 2)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn5));
-			will(returnValue(txn5));
 			oneOf(db).getMessageState(txn5, messageId3);
 			will(returnValue(DELIVERED)); // Already delivered
-			oneOf(db).commitTransaction(txn5);
-			oneOf(db).endTransaction(txn5);
 			// Check whether message 4 is ready to be delivered (via 1 and 3)
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn6));
-			will(returnValue(txn6));
 			oneOf(db).getMessageState(txn6, messageId4);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn6, messageId4);
@@ -930,8 +758,6 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Message 4 has no pending dependents
 			oneOf(db).getMessageDependents(txn6, messageId4);
 			will(returnValue(emptyMap()));
-			oneOf(db).commitTransaction(txn6);
-			oneOf(db).endTransaction(txn6);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));
@@ -946,20 +772,16 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 		Transaction txn1 = new Transaction(null, false);
 		Transaction txn2 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Load the group
-			oneOf(db).startTransaction(true);
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(db).getGroup(txn, groupId);
 			will(returnValue(group));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 			// Validate the message: valid
 			oneOf(validator).validateMessage(message, group);
 			will(returnValue(validResult));
 			// Store the validation result
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			oneOf(db).mergeMessageMetadata(txn1, messageId, metadata);
 			// Deliver the message
 			oneOf(hook).incomingMessage(txn1, message, metadata);
@@ -968,17 +790,12 @@ public class ValidationManagerImplTest extends BrambleMockTestCase {
 			// Get any pending dependents
 			oneOf(db).getMessageDependents(txn1, messageId);
 			will(returnValue(singletonMap(messageId1, PENDING)));
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 			// Check whether the pending dependent is ready to be delivered
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn2));
-			will(returnValue(txn2));
 			oneOf(db).getMessageState(txn2, messageId1);
 			will(returnValue(PENDING));
 			oneOf(db).getMessageDependencies(txn2, messageId1);
 			will(returnValue(twoDependencies));
-			oneOf(db).commitTransaction(txn2);
-			oneOf(db).endTransaction(txn2);
 		}});
 
 		vm.eventOccurred(new MessageAddedEvent(message, contactId));

bramble-core/src/test/java/org/briarproject/bramble/transport/KeyManagerImplTest.java

@@ -15,6 +15,7 @@ import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.jmock.lib.concurrent.DeterministicExecutor;
 import org.junit.Before;
@@ -35,6 +36,7 @@ import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 
 public class KeyManagerImplTest extends BrambleMockTestCase {
 
@@ -77,7 +79,7 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 				singletonList(pluginFactory);
 		int maxLatency = 1337;
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			oneOf(pluginConfig).getSimplexFactories();
 			will(returnValue(factories));
 			oneOf(pluginFactory).getId();
@@ -89,13 +91,10 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 					.createTransportKeyManager(transportId, maxLatency);
 			will(returnValue(transportKeyManager));
 			oneOf(pluginConfig).getDuplexFactories();
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
 			oneOf(transportKeyManager).start(txn);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		keyManager.startService();
@@ -121,25 +120,20 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testGetStreamContextForInactiveContact() throws Exception {
-		assertEquals(null,
+		assertNull(keyManager.getStreamContext(inactiveContactId, transportId));
-				keyManager.getStreamContext(inactiveContactId, transportId));
 	}
 
 	@Test
 	public void testGetStreamContextForUnknownTransport() throws Exception {
-		assertEquals(null,
+		assertNull(keyManager.getStreamContext(contactId, unknownTransportId));
-				keyManager.getStreamContext(contactId, unknownTransportId));
 	}
 
 	@Test
 	public void testGetStreamContextForContact() throws Exception {
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(transportKeyManager).getStreamContext(txn, contactId);
 			will(returnValue(streamContext));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(streamContext,
@@ -149,19 +143,15 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testGetStreamContextForTagAndUnknownTransport()
 			throws Exception {
-		assertEquals(null,
+		assertNull(keyManager.getStreamContext(unknownTransportId, tag));
-				keyManager.getStreamContext(unknownTransportId, tag));
 	}
 
 	@Test
 	public void testGetStreamContextForTag() throws Exception {
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(transportKeyManager).getStreamContext(txn, tag);
 			will(returnValue(streamContext));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(streamContext,
@@ -178,7 +168,7 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 
 		keyManager.eventOccurred(event);
 		executor.runUntilIdle();
-		assertEquals(null, keyManager.getStreamContext(contactId, transportId));
+		assertNull(keyManager.getStreamContext(contactId, transportId));
 	}
 
 	@Test
@@ -186,13 +176,10 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
 		ContactStatusChangedEvent event =
 				new ContactStatusChangedEvent(inactiveContactId, true);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
-			will(returnValue(txn));
 			oneOf(transportKeyManager).getStreamContext(txn, inactiveContactId);
 			will(returnValue(streamContext));
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		keyManager.eventOccurred(event);

bramble-core/src/test/java/org/briarproject/bramble/transport/TransportKeyManagerImplTest.java

@@ -14,6 +14,7 @@ import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.StreamContext;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.briarproject.bramble.test.RunAction;
 import org.briarproject.bramble.test.TestUtils;
 import org.hamcrest.Description;
@@ -318,7 +319,7 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 		Transaction txn = new Transaction(null, false);
 		Transaction txn1 = new Transaction(null, false);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
 			// Get the current time (the start of rotation period 1000)
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(rotationPeriodLength * 1000));
@@ -342,8 +343,7 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 			oneOf(dbExecutor).execute(with(any(Runnable.class)));
 			will(new RunAction());
 			// Start a transaction for key rotation
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn1));
-			will(returnValue(txn1));
 			// Get the current time (the start of rotation period 1001)
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(rotationPeriodLength * 1001));
@@ -364,9 +364,6 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 			// Schedule key rotation at the start of the next rotation period
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with(rotationPeriodLength), with(MILLISECONDS));
-			// Commit the key rotation transaction
-			oneOf(db).commitTransaction(txn1);
-			oneOf(db).endTransaction(txn1);
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManagerImpl(
@@ -539,7 +536,7 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 		}
 
 		@Override
-		public Object invoke(Invocation invocation) throws Throwable {
+		public Object invoke(Invocation invocation) {
 			byte[] tag = (byte[]) invocation.getParameter(0);
 			random.nextBytes(tag);
 			if (tags != null) tags.add(tag);

bramble-core/src/test/java/org/briarproject/bramble/versioning/ClientVersioningManagerImplTest.java

@@ -18,6 +18,7 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager.ClientVersioningHook;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.junit.Test;
 
@@ -63,7 +64,7 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 	private final long now = System.currentTimeMillis();
 	private final Transaction txn = new Transaction(null, false);
 
-	private ClientVersioningManagerImpl createInstance() throws Exception {
+	private ClientVersioningManagerImpl createInstance() {
 		context.checking(new Expectations() {{
 			oneOf(contactGroupFactory).createLocalGroup(CLIENT_ID,
 					MAJOR_VERSION);
@@ -162,9 +163,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfList localUpdateBody = BdfList.of(BdfList.of(
 				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// No client versions have been stored yet
 			oneOf(db).getMessageIds(txn, localGroup.getId());
 			will(returnValue(emptyList()));
@@ -190,8 +190,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).getMessageAsList(txn, localUpdateId);
 			will(returnValue(localUpdateBody));
 			// Latest local update is up-to-date, no visibilities have changed
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		ClientVersioningManagerImpl c = createInstance();
@@ -206,17 +204,14 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfList localVersionsBody =
 				BdfList.of(BdfList.of(clientId.getString(), 123, 234));
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// Load the old client versions
 			oneOf(db).getMessageIds(txn, localGroup.getId());
 			will(returnValue(singletonList(localVersionsId)));
 			oneOf(clientHelper).getMessageAsList(txn, localVersionsId);
 			will(returnValue(localVersionsBody));
 			// Client versions are up-to-date
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		ClientVersioningManagerImpl c = createInstance();
@@ -251,9 +246,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// Load the old client versions
 			oneOf(db).getMessageIds(txn, localGroup.getId());
 			will(returnValue(singletonList(oldLocalVersionsId)));
@@ -295,8 +289,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).addLocalMessage(txn, newLocalUpdate,
 					newLocalUpdateMeta, true);
 			// No visibilities have changed
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		ClientVersioningManagerImpl c = createInstance();
@@ -350,9 +342,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
 
-		context.checking(new Expectations() {{
+		context.checking(new DbExpectations() {{
-			oneOf(db).startTransaction(false);
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			will(returnValue(txn));
 			// Load the old client versions
 			oneOf(db).getMessageIds(txn, localGroup.getId());
 			will(returnValue(singletonList(oldLocalVersionsId)));
@@ -397,8 +388,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 					newLocalUpdateMeta, true);
 			// The client's visibility has changed
 			oneOf(hook).onClientVisibilityChanging(txn, contact, visibility);
-			oneOf(db).commitTransaction(txn);
-			oneOf(db).endTransaction(txn);
 		}});
 
 		ClientVersioningManagerImpl c = createInstance();