Removed database locking.

briar-core/src/org/briarproject/db/Database.java

@@ -30,27 +30,23 @@ import java.util.Map;
  * obtained by calling {@link #startTransaction()}. Every transaction must be
  * terminated by calling either {@link #abortTransaction(T)} or
  * {@link #commitTransaction(T)}, even if an exception is thrown.
- * <p>
- * Read-write locking is provided by the DatabaseComponent implementation.
  */
 interface Database<T> {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
-	 * <p>
-	 * Locking: write.
 	 */
 	boolean open() throws DbException;
 
 	/**
 	 * Prevents new transactions from starting, waits for all current
 	 * transactions to finish, and closes the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void close() throws DbException, IOException;
 
-	/** Starts a new transaction and returns an object representing it. */
+	/**
+	 * Starts a new transaction and returns an object representing it.
+	 */
 	T startTransaction() throws DbException;
 
 	/**
@@ -65,58 +61,38 @@ interface Database<T> {
 	 */
 	void commitTransaction(T txn) throws DbException;
 
-	/**
-	 * Returns the number of transactions started since the transaction count
-	 * was last reset.
-	 */
-	int getTransactionCount();
-
-	/**  Resets the transaction count. */
-	void resetTransactionCount();
-
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	ContactId addContact(T txn, Author remote, AuthorId local)
 			throws DbException;
 
 	/**
 	 * Stores a group.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addGroup(T txn, Group g) throws DbException;
 
 	/**
 	 * Stores a local pseudonym.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addLocalAuthor(T txn, LocalAuthor a) throws DbException;
 
 	/**
 	 * Stores a message.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addMessage(T txn, Message m, Validity validity, boolean shared)
 			throws DbException;
 
 	/**
 	 * Records that a message has been offered by the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addOfferedMessage(T txn, ContactId c, MessageId m) throws DbException;
 
 	/**
 	 * Initialises the status of the given message with respect to the given
 	 * contact.
-	 * <p>
-	 * Locking: write.
+	 *
 	 * @param ack  whether the message needs to be acknowledged.
 	 * @param seen whether the contact has seen the message.
 	 */
@@ -125,76 +101,56 @@ interface Database<T> {
 
 	/**
 	 * Stores a transport.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addTransport(T txn, TransportId t, int maxLatency)
 			throws DbException;
 
 	/**
 	 * Stores transport keys for a newly added contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addTransportKeys(T txn, ContactId c, TransportKeys k)
 			throws DbException;
 
 	/**
 	 * Makes a group visible to the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void addVisibility(T txn, ContactId c, GroupId g) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact for the given
 	 * local pseudonym.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsContact(T txn, AuthorId remote, AuthorId local)
 			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsContact(T txn, ContactId c) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given group.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsGroup(T txn, GroupId g) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given local pseudonym.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsLocalAuthor(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given message.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsMessage(T txn, MessageId m) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given transport.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsTransport(T txn, TransportId t) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given group and the group is
 	 * visible to the given contact.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsVisibleGroup(T txn, ContactId c, GroupId g)
 			throws DbException;
@@ -202,16 +158,12 @@ interface Database<T> {
 	/**
 	 * Returns true if the database contains the given message and the message
 	 * is visible to the given contact.
-	 * <p>
-	 * Locking: read.
 	 */
 	boolean containsVisibleMessage(T txn, ContactId c, MessageId m)
 			throws DbException;
 
 	/**
 	 * Returns the number of messages offered by the given contact.
-	 * <p>
-	 * Locking: read.
 	 */
 	int countOfferedMessages(T txn, ContactId c) throws DbException;
 
@@ -234,36 +186,26 @@ interface Database<T> {
 
 	/**
 	 * Returns the contact with the given ID.
-	 * <p>
-	 * Locking: read.
 	 */
 	Contact getContact(T txn, ContactId c) throws DbException;
 
 	/**
 	 * Returns the IDs of all contacts.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<ContactId> getContactIds(T txn) throws DbException;
 
 	/**
 	 * Returns all contacts.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<Contact> getContacts(T txn) throws DbException;
 
 	/**
 	 * Returns all contacts associated with the given local pseudonym.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<ContactId> getContacts(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns the unique ID for this device.
-	 * <p>
-	 * Locking: read.
 	 */
 	DeviceId getDeviceId(T txn) throws DbException;
 
@@ -276,59 +218,43 @@ interface Database<T> {
 
 	/**
 	 * Returns the group with the given ID.
-	 * <p>
-	 * Locking: read.
 	 */
 	Group getGroup(T txn, GroupId g) throws DbException;
 
 	/**
 	 * Returns the metadata for the given group.
-	 * <p>
-	 * Locking: read.
 	 */
 	Metadata getGroupMetadata(T txn, GroupId g) throws DbException;
 
 	/**
 	 * Returns all groups belonging to the given client.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<Group> getGroups(T txn, ClientId c) throws DbException;
 
 	/**
 	 * Returns the local pseudonym with the given ID.
-	 * <p>
-	 * Locking: read.
 	 */
 	LocalAuthor getLocalAuthor(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns all local pseudonyms.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<LocalAuthor> getLocalAuthors(T txn) throws DbException;
 
 	/**
 	 * Returns the metadata for all messages in the given group.
-	 * <p>
-	 * Locking: read.
 	 */
 	Map<MessageId, Metadata> getMessageMetadata(T txn, GroupId g)
 			throws DbException;
 
 	/**
 	 * Returns the metadata for the given message.
-	 * <p>
-	 * Locking: read.
 	 */
 	Metadata getMessageMetadata(T txn, MessageId m) throws DbException;
 
 	/**
 	 * Returns the status of all messages in the given group with respect
 	 * to the given contact.
-	 * <p>
-	 * Locking: read
 	 */
 	Collection<MessageStatus> getMessageStatus(T txn, ContactId c, GroupId g)
 			throws DbException;
@@ -336,8 +262,6 @@ interface Database<T> {
 	/**
 	 * Returns the status of the given message with respect to the given
 	 * contact.
-	 * <p>
-	 * Locking: read
 	 */
 	MessageStatus getMessageStatus(T txn, ContactId c, MessageId m)
 			throws DbException;
@@ -345,8 +269,6 @@ interface Database<T> {
 	/**
 	 * Returns the IDs of some messages received from the given contact that
 	 * need to be acknowledged, up to the given number of messages.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getMessagesToAck(T txn, ContactId c, int maxMessages)
 			throws DbException;
@@ -354,8 +276,6 @@ interface Database<T> {
 	/**
 	 * Returns the IDs of some messages that are eligible to be offered to the
 	 * given contact, up to the given number of messages.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getMessagesToOffer(T txn, ContactId c,
 			int maxMessages) throws DbException;
@@ -363,8 +283,6 @@ interface Database<T> {
 	/**
 	 * Returns the IDs of some messages that are eligible to be sent to the
 	 * given contact, up to the given total length.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getMessagesToSend(T txn, ContactId c, int maxLength)
 			throws DbException;
@@ -372,8 +290,6 @@ interface Database<T> {
 	/**
 	 * Returns the IDs of some messages that are eligible to be requested from
 	 * the given contact, up to the given number of messages.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getMessagesToRequest(T txn, ContactId c,
 			int maxMessages) throws DbException;
@@ -381,16 +297,12 @@ interface Database<T> {
 	/**
 	 * Returns the IDs of any messages that need to be validated by the given
 	 * client.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getMessagesToValidate(T txn, ClientId c)
 			throws DbException;
 
 	/**
 	 * Returns the message with the given ID, in serialised form.
-	 * <p>
-	 * Locking: read.
 	 */
 	byte[] getRawMessage(T txn, MessageId m) throws DbException;
 
@@ -398,46 +310,34 @@ interface Database<T> {
 	 * Returns the IDs of some messages that are eligible to be sent to the
 	 * given contact and have been requested by the contact, up to the given
 	 * total length.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<MessageId> getRequestedMessagesToSend(T txn, ContactId c,
 			int maxLength) throws DbException;
 
 	/**
 	 * Returns all settings in the given namespace.
-	 * <p>
-	 * Locking: read.
 	 */
 	Settings getSettings(T txn, String namespace) throws DbException;
 
 	/**
 	 * Returns all transport keys for the given transport.
-	 * <p>
-	 * Locking: read.
 	 */
 	Map<ContactId, TransportKeys> getTransportKeys(T txn, TransportId t)
 			throws DbException;
 
 	/**
 	 * Returns the maximum latencies in milliseconds of all transports.
-	 * <p>
-	 * Locking: read.
 	 */
 	Map<TransportId, Integer> getTransportLatencies(T txn) throws DbException;
 
 	/**
 	 * Returns the IDs of all contacts to which the given group is visible.
-	 * <p>
-	 * Locking: read.
 	 */
 	Collection<ContactId> getVisibility(T txn, GroupId g) throws DbException;
 
 	/**
 	 * Increments the outgoing stream counter for the given contact and
 	 * transport in the given rotation period.
-	 * <p>
-	 * Locking: write.
 	 */
 	void incrementStreamCounter(T txn, ContactId c, TransportId t,
 			long rotationPeriod) throws DbException;
@@ -445,8 +345,6 @@ interface Database<T> {
 	/**
 	 * Marks the given messages as not needing to be acknowledged to the
 	 * given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void lowerAckFlag(T txn, ContactId c, Collection<MessageId> acked)
 			throws DbException;
@@ -454,8 +352,6 @@ interface Database<T> {
 	/**
 	 * Marks the given messages as not having been requested by the given
 	 * contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void lowerRequestedFlag(T txn, ContactId c, Collection<MessageId> requested)
 			throws DbException;
@@ -463,8 +359,6 @@ interface Database<T> {
 	/*
 	 * Merges the given metadata with the existing metadata for the given
 	 * group.
-	 * <p>
-	 * Locking: write.
 	 */
 	void mergeGroupMetadata(T txn, GroupId g, Metadata meta)
 			throws DbException;
@@ -472,8 +366,6 @@ interface Database<T> {
 	/*
 	 * Merges the given metadata with the existing metadata for the given
 	 * message.
-	 * <p>
-	 * Locking: write.
 	 */
 	void mergeMessageMetadata(T txn, MessageId m, Metadata meta)
 			throws DbException;
@@ -481,65 +373,47 @@ interface Database<T> {
 	/**
 	 * Merges the given settings with the existing settings in the given
 	 * namespace.
-	 * <p>
-	 * Locking: write.
 	 */
 	void mergeSettings(T txn, Settings s, String namespace) throws DbException;
 
 	/**
 	 * Marks a message as needing to be acknowledged to the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void raiseAckFlag(T txn, ContactId c, MessageId m) throws DbException;
 
 	/**
 	 * Marks a message as having been requested by the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void raiseRequestedFlag(T txn, ContactId c, MessageId m) throws DbException;
 
 	/**
 	 * Marks a message as having been seen by the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void raiseSeenFlag(T txn, ContactId c, MessageId m) throws DbException;
 
 	/**
 	 * Removes a contact from the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeContact(T txn, ContactId c) throws DbException;
 
 	/**
 	 * Removes a group (and all associated state) from the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeGroup(T txn, GroupId g) throws DbException;
 
 	/**
 	 * Removes a local pseudonym (and all associated state) from the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeLocalAuthor(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeMessage(T txn, MessageId m) throws DbException;
 
 	/**
 	 * Removes an offered message that was offered by the given contact, or
 	 * returns false if there is no such message.
-	 * <p>
-	 * Locking: write.
 	 */
 	boolean removeOfferedMessage(T txn, ContactId c, MessageId m)
 			throws DbException;
@@ -547,70 +421,52 @@ interface Database<T> {
 	/**
 	 * Removes the given offered messages that were offered by the given
 	 * contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeOfferedMessages(T txn, ContactId c,
 			Collection<MessageId> requested) throws DbException;
 
 	/**
 	 * Removes a transport (and all associated state) from the database.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeTransport(T txn, TransportId t) throws DbException;
 
 	/**
 	 * Makes a group invisible to the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void removeVisibility(T txn, ContactId c, GroupId g) throws DbException;
 
 	/**
 	 * Resets the transmission count and expiry time of the given message with
 	 * respect to the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void resetExpiryTime(T txn, ContactId c, MessageId m) throws DbException;
 
 	/**
 	 * Sets the status of the given contact.
-	 * <p>
-	 * Locking: write.
 	 */
 	void setContactStatus(T txn, ContactId c, StorageStatus s)
 			throws DbException;
 
 	/**
 	 * Sets the status of the given local pseudonym.
-	 * <p>
-	 * Locking: write.
 	 */
 	void setLocalAuthorStatus(T txn, AuthorId a, StorageStatus s)
 			throws DbException;
 
 	/**
 	 * Marks the given message as shared or unshared.
-	 * <p>
-	 * Locking: write.
 	 */
 	void setMessageShared(T txn, MessageId m, boolean shared)
 			throws DbException;
 
 	/**
 	 * Marks the given message as valid or invalid.
-	 * <p>
-	 * Locking: write.
 	 */
 	void setMessageValid(T txn, MessageId m, boolean valid) throws DbException;
 
 	/**
 	 * Sets the reordering window for the given contact and transport in the
 	 * given rotation period.
-	 * <p>
-	 * Locking: write.
 	 */
 	void setReorderingWindow(T txn, ContactId c, TransportId t,
 			long rotationPeriod, long base, byte[] bitmap) throws DbException;
@@ -619,16 +475,12 @@ interface Database<T> {
 	 * Updates the transmission count and expiry time of the given message
 	 * with respect to the given contact, using the latency of the transport
 	 * over which it was sent.
-	 * <p>
-	 * Locking: write.
 	 */
 	void updateExpiryTime(T txn, ContactId c, MessageId m, int maxLatency)
 			throws DbException;
 
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
-	 * <p>
-	 * Locking: write.
 	 */
 	void updateTransportKeys(T txn, Map<ContactId, TransportKeys> keys)
 			throws DbException;

briar-core/src/org/briarproject/db/DatabaseComponentImpl.java

@@ -55,7 +55,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -79,12 +79,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	private final Database<T> db;
 	private final EventBus eventBus;
 	private final ShutdownManager shutdown;
+	private final AtomicBoolean closed = new AtomicBoolean(false);
 
-	private final ReentrantReadWriteLock lock =
-			new ReentrantReadWriteLock(true);
-
-	private boolean open = false; // Locking: lock.writeLock
-	private int shutdownHandle = -1; // Locking: lock.writeLock
+	private volatile int shutdownHandle = -1;
 
 	@Inject
 	DatabaseComponentImpl(Database<T> db, EventBus eventBus,
@@ -97,9 +94,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public boolean open() throws DbException {
 		Runnable shutdownHook = new Runnable() {
 			public void run() {
-				lock.writeLock().lock();
 				try {
-					shutdownHandle = -1;
 					close();
 				} catch (DbException e) {
 					if (LOG.isLoggable(WARNING))
@@ -107,40 +102,22 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 				} catch (IOException e) {
 					if (LOG.isLoggable(WARNING))
 						LOG.log(WARNING, e.toString(), e);
-				} finally {
-					lock.writeLock().unlock();
 				}
 			}
 		};
-		lock.writeLock().lock();
-		try {
-			if (open) throw new IllegalStateException();
-			open = true;
 		boolean reopened = db.open();
 		shutdownHandle = shutdown.addShutdownHook(shutdownHook);
 		return reopened;
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void close() throws DbException, IOException {
-		lock.writeLock().lock();
-		try {
-			if (!open) return;
-			open = false;
-			if (shutdownHandle != -1)
+		if (closed.getAndSet(true)) return;
 		shutdown.removeShutdownHook(shutdownHandle);
 		db.close();
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public ContactId addContact(Author remote, AuthorId local)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsLocalAuthor(txn, local))
@@ -154,15 +131,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void addGroup(Group g) throws DbException {
 		boolean added = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g.getId())) {
@@ -174,35 +146,24 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (added) eventBus.broadcast(new GroupAddedEvent(g));
 	}
 
 	public void addLocalAuthor(LocalAuthor a) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
-				if (!db.containsLocalAuthor(txn, a.getId())) {
+			if (!db.containsLocalAuthor(txn, a.getId()))
 				db.addLocalAuthor(txn, a);
-				}
 			db.commitTransaction(txn);
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void addLocalMessage(Message m, ClientId c, Metadata meta,
 			boolean shared) throws DbException {
 		boolean added = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, m.getGroupId()))
@@ -217,9 +178,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (added) {
 			eventBus.broadcast(new MessageAddedEvent(m, null));
 			eventBus.broadcast(new MessageValidatedEvent(m, c, true, true));
@@ -229,8 +187,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	/**
 	 * Stores a message and initialises its status with respect to each contact.
-	 * <p>
-	 * Locking: write.
+	 *
 	 * @param sender null for a locally generated message.
 	 */
 	private void addMessage(T txn, Message m, Validity validity, boolean shared,
@@ -253,8 +210,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	public void addTransport(TransportId t, int maxLatency) throws DbException {
 		boolean added = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsTransport(txn, t)) {
@@ -266,16 +221,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (added) eventBus.broadcast(new TransportAddedEvent(t, maxLatency));
 	}
 
 	public void addTransportKeys(ContactId c, TransportKeys k)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -288,9 +238,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void deleteMessage(MessageId m) throws DbException {
@@ -329,8 +276,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	public Ack generateAck(ContactId c, int maxMessages) throws DbException {
 		Collection<MessageId> ids;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -342,9 +287,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (ids.isEmpty()) return null;
 		return new Ack(ids);
 	}
@@ -353,8 +295,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			int maxLatency) throws DbException {
 		Collection<MessageId> ids;
 		List<byte[]> messages = new ArrayList<byte[]>();
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -370,9 +310,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (messages.isEmpty()) return null;
 		if (!ids.isEmpty()) eventBus.broadcast(new MessagesSentEvent(c, ids));
 		return Collections.unmodifiableList(messages);
@@ -381,23 +318,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public Offer generateOffer(ContactId c, int maxMessages, int maxLatency)
 			throws DbException {
 		Collection<MessageId> ids;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
 				throw new NoSuchContactException();
 			ids = db.getMessagesToOffer(txn, c, maxMessages);
-				for (MessageId m : ids)
-					db.updateExpiryTime(txn, c, m, maxLatency);
+			for (MessageId m : ids) db.updateExpiryTime(txn, c, m, maxLatency);
 			db.commitTransaction(txn);
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (ids.isEmpty()) return null;
 		return new Offer(ids);
 	}
@@ -405,8 +336,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public Request generateRequest(ContactId c, int maxMessages)
 			throws DbException {
 		Collection<MessageId> ids;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -418,9 +347,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (ids.isEmpty()) return null;
 		return new Request(ids);
 	}
@@ -429,8 +355,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			int maxLatency) throws DbException {
 		Collection<MessageId> ids;
 		List<byte[]> messages = new ArrayList<byte[]>();
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -446,17 +370,12 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (messages.isEmpty()) return null;
 		if (!ids.isEmpty()) eventBus.broadcast(new MessagesSentEvent(c, ids));
 		return Collections.unmodifiableList(messages);
 	}
 
 	public Contact getContact(ContactId c) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -468,14 +387,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<Contact> getContacts() throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Collection<Contact> contacts = db.getContacts(txn);
@@ -485,14 +399,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<ContactId> getContacts(AuthorId a) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsLocalAuthor(txn, a))
@@ -504,14 +413,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public DeviceId getDeviceId() throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			DeviceId id = db.getDeviceId(txn);
@@ -521,14 +425,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Group getGroup(GroupId g) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
@@ -540,14 +439,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Metadata getGroupMetadata(GroupId g) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
@@ -559,14 +453,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<Group> getGroups(ClientId c) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Collection<Group> groups = db.getGroups(txn, c);
@@ -576,14 +465,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public LocalAuthor getLocalAuthor(AuthorId a) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsLocalAuthor(txn, a))
@@ -595,14 +479,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<LocalAuthor> getLocalAuthors() throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Collection<LocalAuthor> authors = db.getLocalAuthors(txn);
@@ -612,15 +491,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<MessageId> getMessagesToValidate(ClientId c)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Collection<MessageId> ids = db.getMessagesToValidate(txn, c);
@@ -630,14 +504,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public byte[] getRawMessage(MessageId m) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsMessage(txn, m))
@@ -649,35 +518,24 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Map<MessageId, Metadata> getMessageMetadata(GroupId g)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
 				throw new NoSuchGroupException();
-				Map<MessageId, Metadata> metadata =
-						db.getMessageMetadata(txn, g);
+			Map<MessageId, Metadata> metadata = db.getMessageMetadata(txn, g);
 			db.commitTransaction(txn);
 			return metadata;
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Metadata getMessageMetadata(MessageId m) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsMessage(txn, m))
@@ -689,38 +547,27 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<MessageStatus> getMessageStatus(ContactId c, GroupId g)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
 				throw new NoSuchContactException();
 			if (!db.containsGroup(txn, g))
 				throw new NoSuchGroupException();
-				Collection<MessageStatus> statuses =
-						db.getMessageStatus(txn, c, g);
+			Collection<MessageStatus> statuses = db.getMessageStatus(txn, c, g);
 			db.commitTransaction(txn);
 			return statuses;
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public MessageStatus getMessageStatus(ContactId c, MessageId m)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -734,14 +581,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Settings getSettings(String namespace) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Settings s = db.getSettings(txn, namespace);
@@ -751,54 +593,37 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Map<ContactId, TransportKeys> getTransportKeys(TransportId t)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsTransport(txn, t))
 				throw new NoSuchTransportException();
-				Map<ContactId, TransportKeys> keys =
-						db.getTransportKeys(txn, t);
+			Map<ContactId, TransportKeys> keys = db.getTransportKeys(txn, t);
 			db.commitTransaction(txn);
 			return keys;
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Map<TransportId, Integer> getTransportLatencies()
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
-				Map<TransportId, Integer> latencies =
-						db.getTransportLatencies(txn);
+			Map<TransportId, Integer> latencies = db.getTransportLatencies(txn);
 			db.commitTransaction(txn);
 			return latencies;
 		} catch (DbException e) {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public Collection<ContactId> getVisibility(GroupId g) throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
@@ -810,15 +635,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public void incrementStreamCounter(ContactId c, TransportId t,
 			long rotationPeriod) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -831,15 +651,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public boolean isVisibleToContact(ContactId c, GroupId g)
 			throws DbException {
-		lock.readLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -853,15 +668,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.readLock().unlock();
-		}
 	}
 
 	public void mergeGroupMetadata(GroupId g, Metadata meta)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
@@ -872,15 +682,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void mergeMessageMetadata(MessageId m, Metadata meta)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsMessage(txn, m))
@@ -891,15 +696,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void mergeSettings(Settings s, String namespace) throws DbException {
 		boolean changed = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Settings old = db.getSettings(txn, namespace);
@@ -915,16 +715,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (changed) eventBus.broadcast(new SettingsUpdatedEvent(namespace));
 	}
 
 	public void receiveAck(ContactId c, Ack a) throws DbException {
 		Collection<MessageId> acked = new ArrayList<MessageId>();
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -940,16 +735,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		eventBus.broadcast(new MessagesAckedEvent(c, acked));
 	}
 
 	public void receiveMessage(ContactId c, Message m) throws DbException {
 		boolean duplicate, visible;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -965,9 +755,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (visible) {
 			if (!duplicate) eventBus.broadcast(new MessageAddedEvent(m, c));
 			eventBus.broadcast(new MessageToAckEvent(c));
@@ -976,8 +763,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	public void receiveOffer(ContactId c, Offer o) throws DbException {
 		boolean ack = false, request = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -999,17 +784,12 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (ack) eventBus.broadcast(new MessageToAckEvent(c));
 		if (request) eventBus.broadcast(new MessageToRequestEvent(c));
 	}
 
 	public void receiveRequest(ContactId c, Request r) throws DbException {
 		boolean requested = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -1026,15 +806,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (requested) eventBus.broadcast(new MessageRequestedEvent(c));
 	}
 
 	public void removeContact(ContactId c) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -1045,15 +820,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void removeGroup(Group g) throws DbException {
 		Collection<ContactId> affected;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			GroupId id = g.getId();
@@ -1066,16 +836,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		eventBus.broadcast(new GroupRemovedEvent(g));
 		eventBus.broadcast(new GroupVisibilityUpdatedEvent(affected));
 	}
 
 	public void removeLocalAuthor(AuthorId a) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsLocalAuthor(txn, a))
@@ -1086,14 +851,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void removeTransport(TransportId t) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsTransport(txn, t))
@@ -1104,16 +864,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		eventBus.broadcast(new TransportRemovedEvent(t));
 	}
 
 	public void setContactStatus(ContactId c, StorageStatus s)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -1124,15 +879,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void setLocalAuthorStatus(AuthorId a, StorageStatus s)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsLocalAuthor(txn, a))
@@ -1143,15 +893,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void setMessageShared(Message m, boolean shared)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsMessage(txn, m.getId()))
@@ -1162,16 +907,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (shared) eventBus.broadcast(new MessageSharedEvent(m));
 	}
 
 	public void setMessageValid(Message m, ClientId c, boolean valid)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsMessage(txn, m.getId()))
@@ -1182,16 +922,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		eventBus.broadcast(new MessageValidatedEvent(m, c, false, valid));
 	}
 
 	public void setReorderingWindow(ContactId c, TransportId t,
 			long rotationPeriod, long base, byte[] bitmap) throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -1204,16 +939,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 
 	public void setVisibility(GroupId g, Collection<ContactId> visible)
 			throws DbException {
 		Collection<ContactId> affected = new ArrayList<ContactId>();
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsGroup(txn, g))
@@ -1239,9 +969,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (!affected.isEmpty())
 			eventBus.broadcast(new GroupVisibilityUpdatedEvent(affected));
 	}
@@ -1249,8 +976,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public void setVisibleToContact(ContactId c, GroupId g, boolean visible)
 			throws DbException {
 		boolean wasVisible = false;
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			if (!db.containsContact(txn, c))
@@ -1265,9 +990,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 		if (visible != wasVisible) {
 			eventBus.broadcast(new GroupVisibilityUpdatedEvent(
 					Collections.singletonList(c)));
@@ -1276,8 +998,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	public void updateTransportKeys(Map<ContactId, TransportKeys> keys)
 			throws DbException {
-		lock.writeLock().lock();
-		try {
 		T txn = db.startTransaction();
 		try {
 			Map<ContactId, TransportKeys> filtered =
@@ -1296,8 +1016,5 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			db.abortTransaction(txn);
 			throw e;
 		}
-		} finally {
-			lock.writeLock().unlock();
-		}
 	}
 }

briar-core/src/org/briarproject/db/JdbcDatabase.java

@@ -41,7 +41,6 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -228,8 +227,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private final LinkedList<Connection> connections =
 			new LinkedList<Connection>(); // Locking: connectionsLock
 
-	private final AtomicInteger transactionCount = new AtomicInteger(0);
-
 	private int openConnections = 0; // Locking: connectionsLock
 	private boolean closed = false; // Locking: connectionsLock
 
@@ -369,7 +366,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		} catch (SQLException e) {
 			throw new DbException(e);
 		}
-		transactionCount.incrementAndGet();
 		return txn;
 	}
 
@@ -418,14 +414,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	public int getTransactionCount() {
-		return transactionCount.get();
-	}
-
-	public void resetTransactionCount() {
-		transactionCount.set(0);
-	}
-
 	protected void closeAllConnections() throws SQLException {
 		boolean interrupted = false;
 		connectionsLock.lock();