Replaced Timer with ScheduledExecutorService. #258

briar-android-tests/src/test/java/org/briarproject/IntroductionIntegrationTest.java

@@ -42,6 +42,7 @@ import org.briarproject.introduction.MessageSender;
 import org.briarproject.lifecycle.LifecycleModule;
 import org.briarproject.properties.PropertiesModule;
 import org.briarproject.sync.SyncModule;
+import org.briarproject.system.SystemModule;
 import org.briarproject.transport.TransportModule;
 import org.junit.After;
 import org.junit.Before;
@@ -944,6 +945,7 @@ public class IntroductionIntegrationTest extends BriarTestCase {
 			this.accept = accept;
 		}
 
+		@Override
 		public void eventOccurred(Event e) {
 			if (e instanceof MessageValidatedEvent) {
 				MessageValidatedEvent event = (MessageValidatedEvent) e;
@@ -1010,6 +1012,7 @@ public class IntroductionIntegrationTest extends BriarTestCase {
 		public volatile boolean response2Received = false;
 		public volatile boolean aborted = false;
 
+		@Override
 		public void eventOccurred(Event e) {
 			if (e instanceof MessageValidatedEvent) {
 				MessageValidatedEvent event = (MessageValidatedEvent) e;
@@ -1050,7 +1053,7 @@ public class IntroductionIntegrationTest extends BriarTestCase {
 		component.inject(new ContactModule.EagerSingletons());
 		component.inject(new TransportModule.EagerSingletons());
 		component.inject(new SyncModule.EagerSingletons());
+		component.inject(new SystemModule.EagerSingletons());
 		component.inject(new PropertiesModule.EagerSingletons());
 	}
-
 }

briar-android-tests/src/test/java/org/briarproject/IntroductionIntegrationTestComponent.java

@@ -21,6 +21,7 @@ import org.briarproject.introduction.MessageSender;
 import org.briarproject.lifecycle.LifecycleModule;
 import org.briarproject.properties.PropertiesModule;
 import org.briarproject.sync.SyncModule;
+import org.briarproject.system.SystemModule;
 import org.briarproject.transport.TransportModule;
 
 import javax.inject.Singleton;
@@ -29,9 +30,9 @@ import dagger.Component;
 
 @Singleton
 @Component(modules = {
-		TestSystemModule.class,
 		TestDatabaseModule.class,
 		TestPluginsModule.class,
+		TestSeedProviderModule.class,
 		LifecycleModule.class,
 		IntroductionModule.class,
 		DatabaseModule.class,
@@ -42,6 +43,7 @@ import dagger.Component;
 		TransportModule.class,
 		ClientsModule.class,
 		SyncModule.class,
+		SystemModule.class,
 		DataModule.class,
 		PropertiesModule.class
 })
@@ -61,6 +63,8 @@ public interface IntroductionIntegrationTestComponent {
 
 	void inject(SyncModule.EagerSingletons init);
 
+	void inject(SystemModule.EagerSingletons init);
+
 	void inject(TransportModule.EagerSingletons init);
 
 	LifecycleManager getLifecycleManager();
@@ -84,5 +88,4 @@ public interface IntroductionIntegrationTestComponent {
 	MessageSender getMessageSender();
 
 	IntroductionGroupFactory getIntroductionGroupFactory();
-
 }

briar-android-tests/src/test/java/org/briarproject/MessageSizeIntegrationTest.java

@@ -13,6 +13,7 @@ import org.briarproject.api.messaging.PrivateMessage;
 import org.briarproject.api.messaging.PrivateMessageFactory;
 import org.briarproject.api.sync.GroupId;
 import org.briarproject.api.sync.MessageId;
+import org.briarproject.system.SystemModule;
 import org.junit.Test;
 
 import javax.inject.Inject;
@@ -39,6 +40,7 @@ public class MessageSizeIntegrationTest extends BriarTestCase {
 		MessageSizeIntegrationTestComponent component =
 				DaggerMessageSizeIntegrationTestComponent.builder().build();
 		component.inject(this);
+		component.inject(new SystemModule.EagerSingletons());
 	}
 
 	@Test

briar-android-tests/src/test/java/org/briarproject/MessageSizeIntegrationTestComponent.java

@@ -9,6 +9,7 @@ import org.briarproject.forum.ForumModule;
 import org.briarproject.identity.IdentityModule;
 import org.briarproject.messaging.MessagingModule;
 import org.briarproject.sync.SyncModule;
+import org.briarproject.system.SystemModule;
 
 import javax.inject.Singleton;
 
@@ -18,7 +19,7 @@ import dagger.Component;
 @Component(modules = {
 		TestDatabaseModule.class,
 		TestLifecycleModule.class,
-		TestSystemModule.class,
+		TestSeedProviderModule.class,
 		ClientsModule.class,
 		CryptoModule.class,
 		DataModule.class,
@@ -27,8 +28,12 @@ import dagger.Component;
 		ForumModule.class,
 		IdentityModule.class,
 		MessagingModule.class,
-		SyncModule.class
+		SyncModule.class,
+		SystemModule.class
 })
 public interface MessageSizeIntegrationTestComponent {
+
 	void inject(MessageSizeIntegrationTest testCase);
+
+	void inject(SystemModule.EagerSingletons init);
 }

briar-android-tests/src/test/java/org/briarproject/SimplexMessagingIntegrationTest.java

@@ -21,6 +21,7 @@ import org.briarproject.api.transport.KeyManager;
 import org.briarproject.api.transport.StreamContext;
 import org.briarproject.api.transport.StreamReaderFactory;
 import org.briarproject.api.transport.StreamWriterFactory;
+import org.briarproject.system.SystemModule;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -57,8 +58,10 @@ public class SimplexMessagingIntegrationTest extends BriarTestCase {
 		assertTrue(testDir.mkdirs());
 		alice = DaggerSimplexMessagingIntegrationTestComponent.builder()
 				.testDatabaseModule(new TestDatabaseModule(aliceDir)).build();
+		alice.inject(new SystemModule.EagerSingletons());
 		bob = DaggerSimplexMessagingIntegrationTestComponent.builder()
 				.testDatabaseModule(new TestDatabaseModule(bobDir)).build();
+		bob.inject(new SystemModule.EagerSingletons());
 	}
 
 	@Test
@@ -183,6 +186,7 @@ public class SimplexMessagingIntegrationTest extends BriarTestCase {
 
 		private volatile boolean messageAdded = false;
 
+		@Override
 		public void eventOccurred(Event e) {
 			if (e instanceof MessageAddedEvent) messageAdded = true;
 		}

briar-android-tests/src/test/java/org/briarproject/SimplexMessagingIntegrationTestComponent.java

@@ -21,6 +21,7 @@ import org.briarproject.lifecycle.LifecycleModule;
 import org.briarproject.messaging.MessagingModule;
 import org.briarproject.plugins.PluginsModule;
 import org.briarproject.sync.SyncModule;
+import org.briarproject.system.SystemModule;
 import org.briarproject.transport.TransportModule;
 
 import javax.inject.Singleton;
@@ -31,7 +32,7 @@ import dagger.Component;
 @Component(modules = {
 		TestDatabaseModule.class,
 		TestPluginsModule.class,
-		TestSystemModule.class,
+		TestSeedProviderModule.class,
 		ClientsModule.class,
 		ContactModule.class,
 		CryptoModule.class,
@@ -43,11 +44,12 @@ import dagger.Component;
 		MessagingModule.class,
 		PluginsModule.class,
 		SyncModule.class,
+		SystemModule.class,
 		TransportModule.class
 })
 public interface SimplexMessagingIntegrationTestComponent {
 
-	void inject(SimplexMessagingIntegrationTest testCase);
+	void inject(SystemModule.EagerSingletons init);
 
 	LifecycleManager getLifecycleManager();
 

briar-android-tests/src/test/java/org/briarproject/SyncIntegrationTestComponent.java

@@ -10,7 +10,7 @@ import dagger.Component;
 
 @Singleton
 @Component(modules = {
-		TestSystemModule.class,
+		TestSeedProviderModule.class,
 		CryptoModule.class,
 		SyncModule.class,
 		TransportModule.class

briar-android/src/org/briarproject/system/AndroidSystemModule.java

@@ -15,6 +15,7 @@ import dagger.Provides;
 public class AndroidSystemModule {
 
 	@Provides
+	@Singleton
 	public SeedProvider provideSeedProvider(Application app) {
 		return new AndroidSeedProvider(app);
 	}

briar-api/src/org/briarproject/api/system/Timer.java

@@ -1,27 +0,0 @@
-package org.briarproject.api.system;
-
-import java.util.TimerTask;
-
-/**
- * A wrapper around a {@link java.util.Timer} that allows it to be replaced for
- * testing.
- */
-public interface Timer {
-
-	/** @see {@link java.util.Timer#cancel()} */
-	void cancel();
-
-	/** @see {@link java.util.Timer#purge()} */
-	int purge();
-
-	/** @see {@link java.util.Timer#schedule(TimerTask, long)} */
-	void schedule(TimerTask task, long delay);
-
-	/** @see {@link java.util.Timer#schedule(TimerTask, long, long)} */
-	void schedule(TimerTask task, long delay, long period);
-
-	/**
-	 * @see {@link java.util.Timer#scheduleAtFixedRate(TimerTask, long, long)}
-	 */
-	void scheduleAtFixedRate(TimerTask task, long delay, long period);
-}

briar-core/src/org/briarproject/CoreEagerSingletons.java

@@ -10,6 +10,7 @@ import org.briarproject.messaging.MessagingModule;
 import org.briarproject.plugins.PluginsModule;
 import org.briarproject.properties.PropertiesModule;
 import org.briarproject.sync.SyncModule;
+import org.briarproject.system.SystemModule;
 import org.briarproject.transport.TransportModule;
 
 public interface CoreEagerSingletons {
@@ -34,5 +35,7 @@ public interface CoreEagerSingletons {
 
 	void inject(SyncModule.EagerSingletons init);
 
+	void inject(SystemModule.EagerSingletons init);
+
 	void inject(TransportModule.EagerSingletons init);
 }

briar-core/src/org/briarproject/CoreModule.java

@@ -61,6 +61,7 @@ public class CoreModule {
 		c.inject(new PluginsModule.EagerSingletons());
 		c.inject(new PropertiesModule.EagerSingletons());
 		c.inject(new SyncModule.EagerSingletons());
+		c.inject(new SystemModule.EagerSingletons());
 		c.inject(new TransportModule.EagerSingletons());
 		c.inject(new IntroductionModule.EagerSingletons());
 	}

briar-core/src/org/briarproject/plugins/PluginManagerImpl.java

@@ -122,9 +122,6 @@ class PluginManagerImpl implements PluginManager, Service, EventListener {
 	public void stopService() throws ServiceException {
 		// Stop listening for events
 		eventBus.removeListener(this);
-		// Stop the poller
-		LOG.info("Stopping poller");
-		poller.stop();
 		final CountDownLatch latch = new CountDownLatch(plugins.size());
 		// Stop the simplex plugins
 		LOG.info("Stopping simplex plugins");
@@ -432,7 +429,7 @@ class PluginManagerImpl implements PluginManager, Service, EventListener {
 		public void transportEnabled() {
 			eventBus.broadcast(new TransportEnabledEvent(id));
 			Plugin p = plugins.get(id);
-			if (p != null) poller.pollNow(p);
+			if (p != null && p.shouldPoll()) poller.pollNow(p);
 		}
 
 		@Override

briar-core/src/org/briarproject/plugins/PluginsModule.java

@@ -8,12 +8,10 @@ import org.briarproject.api.plugins.ConnectionManager;
 import org.briarproject.api.plugins.ConnectionRegistry;
 import org.briarproject.api.plugins.PluginManager;
 import org.briarproject.api.sync.SyncSessionFactory;
-import org.briarproject.api.system.Timer;
 import org.briarproject.api.transport.KeyManager;
 import org.briarproject.api.transport.StreamReaderFactory;
 import org.briarproject.api.transport.StreamWriterFactory;
 
-import java.security.SecureRandom;
 import java.util.concurrent.Executor;
 
 import javax.inject.Inject;
@@ -36,10 +34,9 @@ public class PluginsModule {
 	}
 
 	@Provides
-	Poller providePoller(@IoExecutor Executor ioExecutor,
-			ConnectionRegistry connectionRegistry, SecureRandom random,
-			Timer timer) {
-		return new PollerImpl(ioExecutor, connectionRegistry, random, timer);
+	@Singleton
+	Poller providePoller(PollerImpl poller) {
+		return poller;
 	}
 
 	@Provides

briar-core/src/org/briarproject/plugins/Poller.java

@@ -6,7 +6,4 @@ interface Poller {
 
 	/** Tells the poller to poll the given plugin immediately. */
 	void pollNow(Plugin p);
-
-	/** Stops the poller. */
-	void stop();
 }

briar-core/src/org/briarproject/plugins/PollerImpl.java

@@ -4,17 +4,17 @@ import org.briarproject.api.TransportId;
 import org.briarproject.api.lifecycle.IoExecutor;
 import org.briarproject.api.plugins.ConnectionRegistry;
 import org.briarproject.api.plugins.Plugin;
-import org.briarproject.api.system.Timer;
 
 import java.security.SecureRandom;
 import java.util.Map;
-import java.util.TimerTask;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 
 class PollerImpl implements Poller {
@@ -23,31 +23,26 @@ class PollerImpl implements Poller {
 			Logger.getLogger(PollerImpl.class.getName());
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final ConnectionRegistry connectionRegistry;
 	private final SecureRandom random;
-	private final Timer timer;
 	private final Map<TransportId, PollTask> tasks;
 
 	@Inject
 	PollerImpl(@IoExecutor Executor ioExecutor,
-			ConnectionRegistry connectionRegistry, SecureRandom random,
-			Timer timer) {
+			ScheduledExecutorService scheduler,
+			ConnectionRegistry connectionRegistry, SecureRandom random) {
 		this.ioExecutor = ioExecutor;
 		this.connectionRegistry = connectionRegistry;
 		this.random = random;
-		this.timer = timer;
+		this.scheduler = scheduler;
 		tasks = new ConcurrentHashMap<TransportId, PollTask>();
 	}
 
-	@Override
-	public void stop() {
-		timer.cancel();
-	}
-
 	@Override
 	public void pollNow(Plugin p) {
 		// Randomise next polling interval
-		if (p.shouldPoll()) schedule(p, 0, true);
+		schedule(p, 0, true);
 	}
 
 	private void schedule(Plugin p, int interval, boolean randomiseNext) {
@@ -55,7 +50,7 @@ class PollerImpl implements Poller {
 		PollTask task = new PollTask(p, randomiseNext);
 		PollTask replaced = tasks.put(p.getId(), task);
 		if (replaced != null) replaced.cancel();
-		timer.schedule(task, interval);
+		scheduler.schedule(task, interval, MILLISECONDS);
 	}
 
 	private void poll(final Plugin p) {
@@ -69,18 +64,25 @@ class PollerImpl implements Poller {
 		});
 	}
 
-	private class PollTask extends TimerTask {
+	private class PollTask implements Runnable {
 
 		private final Plugin plugin;
 		private final boolean randomiseNext;
 
+		private volatile boolean cancelled = false;
+
 		private PollTask(Plugin plugin, boolean randomiseNext) {
 			this.plugin = plugin;
 			this.randomiseNext = randomiseNext;
 		}
 
+		private void cancel() {
+			cancelled = true;
+		}
+
 		@Override
 		public void run() {
+			if (cancelled) return;
 			tasks.remove(plugin.getId());
 			int interval = plugin.getPollingInterval();
 			if (randomiseNext)

briar-core/src/org/briarproject/system/SystemModule.java

@@ -1,23 +1,41 @@
 package org.briarproject.system;
 
+import org.briarproject.api.lifecycle.LifecycleManager;
 import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.LocationUtils;
-import org.briarproject.api.system.SeedProvider;
-import org.briarproject.api.system.Timer;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
 
 import dagger.Module;
 import dagger.Provides;
 
 @Module
 public class SystemModule {
+
+	public static class EagerSingletons {
+		@Inject
+		ScheduledExecutorService scheduledExecutorService;
+	}
+
+	private final ScheduledExecutorService scheduler;
+
+	public SystemModule() {
+		scheduler = Executors.newSingleThreadScheduledExecutor();
+	}
+
 	@Provides
 	Clock provideClock() {
 		return new SystemClock();
 	}
 
 	@Provides
-	Timer provideTimer() {
-		return new SystemTimer();
+	@Singleton
+	ScheduledExecutorService provideScheduledExecutorService(
+			LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(scheduler);
+		return scheduler;
 	}
-
 }

briar-core/src/org/briarproject/system/SystemTimer.java

@@ -1,31 +0,0 @@
-package org.briarproject.system;
-
-import java.util.TimerTask;
-
-import org.briarproject.api.system.Timer;
-
-/** Default timer implementation. */
-public class SystemTimer implements Timer {
-
-	private final java.util.Timer timer = new java.util.Timer(true);
-
-	public void cancel() {
-		timer.cancel();
-	}
-
-	public int purge() {
-		return timer.purge();
-	}
-
-	public void schedule(TimerTask task, long delay) {
-		timer.schedule(task, delay);
-	}
-
-	public void schedule(TimerTask task, long delay, long period) {
-		timer.schedule(task, delay, period);
-	}
-
-	public void scheduleAtFixedRate(TimerTask task, long delay, long period) {
-		timer.scheduleAtFixedRate(task, delay, period);
-	}
-}

briar-core/src/org/briarproject/transport/KeyManagerImpl.java

@@ -19,7 +19,6 @@ import org.briarproject.api.plugins.PluginConfig;
 import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
 import org.briarproject.api.plugins.simplex.SimplexPluginFactory;
 import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.Timer;
 import org.briarproject.api.transport.KeyManager;
 import org.briarproject.api.transport.StreamContext;
 
@@ -28,6 +27,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -42,21 +42,22 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	private final DatabaseComponent db;
 	private final CryptoComponent crypto;
 	private final Executor dbExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final PluginConfig pluginConfig;
-	private final Timer timer;
 	private final Clock clock;
 	private final Map<ContactId, Boolean> activeContacts;
 	private final ConcurrentHashMap<TransportId, TransportKeyManager> managers;
 
 	@Inject
 	KeyManagerImpl(DatabaseComponent db, CryptoComponent crypto,
-			@DatabaseExecutor Executor dbExecutor, PluginConfig pluginConfig,
-			Timer timer, Clock clock) {
+			@DatabaseExecutor Executor dbExecutor,
+			ScheduledExecutorService scheduler, PluginConfig pluginConfig,
+			Clock clock) {
 		this.db = db;
 		this.crypto = crypto;
 		this.dbExecutor = dbExecutor;
+		this.scheduler = scheduler;
 		this.pluginConfig = pluginConfig;
-		this.timer = timer;
 		this.clock = clock;
 		// Use a ConcurrentHashMap as a thread-safe set
 		activeContacts = new ConcurrentHashMap<ContactId, Boolean>();
@@ -80,7 +81,8 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 					db.addTransport(txn, e.getKey(), e.getValue());
 				for (Entry<TransportId, Integer> e : transports.entrySet()) {
 					TransportKeyManager m = new TransportKeyManager(db, crypto,
-							timer, clock, e.getKey(), e.getValue());
+							dbExecutor, scheduler, clock, e.getKey(),
+							e.getValue());
 					managers.put(e.getKey(), m);
 					m.start(txn);
 				}
@@ -97,12 +99,14 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	public void stopService() {
 	}
 
+	@Override
 	public void addContact(Transaction txn, ContactId c, SecretKey master,
 			long timestamp, boolean alice) throws DbException {
 		for (TransportKeyManager m : managers.values())
 			m.addContact(txn, c, master, timestamp, alice);
 	}
 
+	@Override
 	public StreamContext getStreamContext(ContactId c, TransportId t)
 			throws DbException {
 		// Don't allow outgoing streams to inactive contacts
@@ -123,6 +127,7 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		return ctx;
 	}
 
+	@Override
 	public StreamContext getStreamContext(TransportId t, byte[] tag)
 			throws DbException {
 		TransportKeyManager m = managers.get(t);
@@ -141,6 +146,7 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		return ctx;
 	}
 
+	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof ContactRemovedEvent) {
 			removeContact(((ContactRemovedEvent) e).getContactId());
@@ -154,6 +160,7 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	private void removeContact(final ContactId c) {
 		activeContacts.remove(c);
 		dbExecutor.execute(new Runnable() {
+			@Override
 			public void run() {
 				for (TransportKeyManager m : managers.values())
 					m.removeContact(c);

briar-core/src/org/briarproject/transport/TransportKeyManager.java

@@ -9,7 +9,6 @@ import org.briarproject.api.db.DatabaseComponent;
 import org.briarproject.api.db.DbException;
 import org.briarproject.api.db.Transaction;
 import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.Timer;
 import org.briarproject.api.transport.StreamContext;
 import org.briarproject.api.transport.TransportKeys;
 import org.briarproject.transport.ReorderingWindow.Change;
@@ -18,10 +17,12 @@ import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.TimerTask;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
 import static org.briarproject.api.transport.TransportConstants.TAG_LENGTH;
@@ -34,7 +35,8 @@ class TransportKeyManager {
 
 	private final DatabaseComponent db;
 	private final CryptoComponent crypto;
-	private final Timer timer;
+	private final Executor dbExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Clock clock;
 	private final TransportId transportId;
 	private final long rotationPeriodLength;
@@ -46,11 +48,12 @@ class TransportKeyManager {
 	private final Map<ContactId, MutableTransportKeys> keys;
 
 	TransportKeyManager(DatabaseComponent db, CryptoComponent crypto,
-			Timer timer, Clock clock, TransportId transportId,
-			long maxLatency) {
+			Executor dbExecutor, ScheduledExecutorService scheduler,
+			Clock clock, TransportId transportId, long maxLatency) {
 		this.db = db;
 		this.crypto = crypto;
-		this.timer = timer;
+		this.dbExecutor = dbExecutor;
+		this.scheduler = scheduler;
 		this.clock = clock;
 		this.transportId = transportId;
 		rotationPeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
@@ -122,7 +125,19 @@ class TransportKeyManager {
 	}
 
 	private void scheduleKeyRotation(long now) {
-		TimerTask task = new TimerTask() {
+		Runnable task = new Runnable() {
+			@Override
+			public void run() {
+				rotateKeys();
+			}
+		};
+		long delay = rotationPeriodLength - now % rotationPeriodLength;
+		scheduler.schedule(task, delay, MILLISECONDS);
+	}
+
+	private void rotateKeys() {
+		dbExecutor.execute(new Runnable() {
+			@Override
 			public void run() {
 				try {
 					Transaction txn = db.startTransaction(false);
@@ -137,9 +152,7 @@ class TransportKeyManager {
 						LOG.log(WARNING, e.toString(), e);
 				}
 			}
-		};
-		long delay = rotationPeriodLength - now % rotationPeriodLength;
-		timer.schedule(task, delay);
+		});
 	}
 
 	void addContact(Transaction txn, ContactId c, SecretKey master,

briar-core/src/org/briarproject/transport/TransportModule.java

@@ -18,7 +18,8 @@ import dagger.Provides;
 public class TransportModule {
 
 	public static class EagerSingletons {
-		@Inject KeyManager keyManager;
+		@Inject
+		KeyManager keyManager;
 	}
 
 	@Provides
@@ -35,7 +36,7 @@ public class TransportModule {
 
 	@Provides
 	@Singleton
-	KeyManager getKeyManager(LifecycleManager lifecycleManager,
+	KeyManager provideKeyManager(LifecycleManager lifecycleManager,
 			EventBus eventBus, KeyManagerImpl keyManager) {
 		lifecycleManager.registerService(keyManager);
 		eventBus.addListener(keyManager);

briar-desktop/src/org/briarproject/system/DesktopSeedProviderModule.java

@@ -0,0 +1,19 @@
+package org.briarproject.system;
+
+import org.briarproject.api.system.SeedProvider;
+import org.briarproject.util.OsUtils;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class DesktopSeedProviderModule {
+
+	@Provides
+	@Singleton
+	SeedProvider provideSeedProvider() {
+		return OsUtils.isLinux() ? new LinuxSeedProvider() : null;
+	}
+}

briar-desktop/src/org/briarproject/system/DesktopSystemModule.java

@@ -1,31 +0,0 @@
-package org.briarproject.system;
-
-import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.SeedProvider;
-import org.briarproject.api.system.Timer;
-import org.briarproject.util.OsUtils;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class DesktopSystemModule {
-
-	@Provides
-	Clock provideClock() {
-		return new SystemClock();
-	}
-
-	@Provides
-	Timer provideTimer() {
-		return new SystemTimer();
-	}
-
-	@Provides
-	SeedProvider provideSeedProvider() {
-		if (OsUtils.isLinux()) {
-			return new LinuxSeedProvider();
-		}
-		return null;
-	}
-}

briar-tests/src/org/briarproject/TestSeedProviderModule.java

@@ -0,0 +1,18 @@
+package org.briarproject;
+
+import org.briarproject.api.system.SeedProvider;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class TestSeedProviderModule {
+
+	@Provides
+	@Singleton
+	SeedProvider provideSeedProvider() {
+		return new TestSeedProvider();
+	}
+}

briar-tests/src/org/briarproject/TestSystemModule.java

@@ -1,29 +0,0 @@
-package org.briarproject;
-
-import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.SeedProvider;
-import org.briarproject.api.system.Timer;
-import org.briarproject.system.SystemClock;
-import org.briarproject.system.SystemTimer;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class TestSystemModule {
-
-	@Provides
-	Clock provideClock() {
-		return new SystemClock();
-	}
-
-	@Provides
-	Timer provideSystemTimer() {
-		return new SystemTimer();
-	}
-
-	@Provides
-	SeedProvider provideSeedProvider() {
-		return new TestSeedProvider();
-	}
-}

briar-tests/src/org/briarproject/plugins/PluginManagerImplTest.java

@@ -113,8 +113,6 @@ public class PluginManagerImplTest extends BriarTestCase {
 			// stop()
 			// Stop listening for events
 			oneOf(eventBus).removeListener(with(any(EventListener.class)));
-			// Stop the poller
-			oneOf(poller).stop();
 			// Stop the plugins
 			oneOf(simplexPlugin).stop();
 			oneOf(duplexPlugin).stop();
@@ -248,8 +246,6 @@ public class PluginManagerImplTest extends BriarTestCase {
 			// stop()
 			// Stop listening for events
 			oneOf(eventBus).removeListener(with(any(EventListener.class)));
-			// Stop the poller
-			oneOf(poller).stop();
 			// Stop the plugins
 			oneOf(simplexPlugin).stop();
 			oneOf(simplexPlugin1).stop();

briar-tests/src/org/briarproject/transport/TransportKeyManagerTest.java

@@ -9,7 +9,6 @@ import org.briarproject.api.crypto.SecretKey;
 import org.briarproject.api.db.DatabaseComponent;
 import org.briarproject.api.db.Transaction;
 import org.briarproject.api.system.Clock;
-import org.briarproject.api.system.Timer;
 import org.briarproject.api.transport.IncomingKeys;
 import org.briarproject.api.transport.OutgoingKeys;
 import org.briarproject.api.transport.StreamContext;
@@ -28,8 +27,10 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
-import java.util.TimerTask;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.briarproject.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
 import static org.briarproject.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
 import static org.briarproject.api.transport.TransportConstants.TAG_LENGTH;
@@ -56,11 +57,12 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
-		final Map<ContactId, TransportKeys> loaded =
-				new LinkedHashMap<ContactId, TransportKeys>();
+		final Map<ContactId, TransportKeys> loaded = new LinkedHashMap<>();
 		final TransportKeys shouldRotate = createTransportKeys(900, 0);
 		final TransportKeys shouldNotRotate = createTransportKeys(1000, 0);
 		loaded.put(contactId, shouldRotate);
@@ -90,12 +92,12 @@ public class TransportKeyManagerTest extends BriarTestCase {
 			oneOf(db).updateTransportKeys(txn,
 					Collections.singletonMap(contactId, rotated));
 			// Schedule key rotation at the start of the next rotation period
-			oneOf(timer).schedule(with(any(TimerTask.class)),
-					with(rotationPeriodLength - 1));
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with(rotationPeriodLength - 1), with(MILLISECONDS));
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		transportKeyManager.start(txn);
 
 		context.assertIsSatisfied();
@@ -106,7 +108,9 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final boolean alice = true;
@@ -135,7 +139,7 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		// The timestamp is 1 ms before the start of rotation period 1000
 		long timestamp = rotationPeriodLength * 1000 - 1;
 		transportKeyManager.addContact(txn, contactId, masterKey, timestamp,
@@ -150,13 +154,15 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final Transaction txn = new Transaction(null, false);
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		assertNull(transportKeyManager.getStreamContext(txn, contactId));
 
 		context.assertIsSatisfied();
@@ -168,7 +174,9 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final boolean alice = true;
@@ -198,7 +206,7 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		// The timestamp is at the start of rotation period 1000
 		long timestamp = rotationPeriodLength * 1000;
 		transportKeyManager.addContact(txn, contactId, masterKey, timestamp,
@@ -213,7 +221,9 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final boolean alice = true;
@@ -245,7 +255,7 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		// The timestamp is at the start of rotation period 1000
 		long timestamp = rotationPeriodLength * 1000;
 		transportKeyManager.addContact(txn, contactId, masterKey, timestamp,
@@ -271,7 +281,9 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final boolean alice = true;
@@ -299,7 +311,7 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		// The timestamp is at the start of rotation period 1000
 		long timestamp = rotationPeriodLength * 1000;
 		transportKeyManager.addContact(txn, contactId, masterKey, timestamp,
@@ -315,13 +327,15 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final boolean alice = true;
 		final TransportKeys transportKeys = createTransportKeys(1000, 0);
 		// Keep a copy of the tags
-		final List<byte[]> tags = new ArrayList<byte[]>();
+		final List<byte[]> tags = new ArrayList<>();
 		final Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
@@ -352,7 +366,7 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		// The timestamp is at the start of rotation period 1000
 		long timestamp = rotationPeriodLength * 1000;
 		transportKeyManager.addContact(txn, contactId, masterKey, timestamp,
@@ -381,7 +395,9 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		Mockery context = new Mockery();
 		final DatabaseComponent db = context.mock(DatabaseComponent.class);
 		final CryptoComponent crypto = context.mock(CryptoComponent.class);
-		final Timer timer = context.mock(Timer.class);
+		final Executor dbExecutor = context.mock(Executor.class);
+		final ScheduledExecutorService scheduler =
+				context.mock(ScheduledExecutorService.class);
 		final Clock clock = context.mock(Clock.class);
 
 		final TransportKeys transportKeys = createTransportKeys(1000, 0);
@@ -408,9 +424,11 @@ public class TransportKeyManagerTest extends BriarTestCase {
 				will(new EncodeTagAction());
 			}
 			// Schedule key rotation at the start of the next rotation period
-			oneOf(timer).schedule(with(any(TimerTask.class)),
-					with(rotationPeriodLength));
-			will(new RunTimerTaskAction());
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with(rotationPeriodLength), with(MILLISECONDS));
+			will(new RunAction());
+			oneOf(dbExecutor).execute(with(any(Runnable.class)));
+			will(new RunAction());
 			// Start a transaction for key rotation
 			oneOf(db).startTransaction(false);
 			will(returnValue(txn1));
@@ -431,14 +449,14 @@ public class TransportKeyManagerTest extends BriarTestCase {
 			oneOf(db).updateTransportKeys(txn1,
 					Collections.singletonMap(contactId, rotated));
 			// Schedule key rotation at the start of the next rotation period
-			oneOf(timer).schedule(with(any(TimerTask.class)),
-					with(rotationPeriodLength));
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with(rotationPeriodLength), with(MILLISECONDS));
 			// Commit the key rotation transaction
 			oneOf(db).endTransaction(txn1);
 		}});
 
 		TransportKeyManager transportKeyManager = new TransportKeyManager(db,
-				crypto, timer, clock, transportId, maxLatency);
+				crypto, dbExecutor, scheduler, clock, transportId, maxLatency);
 		transportKeyManager.start(txn);
 		assertTrue(txn1.isComplete());
 
@@ -484,18 +502,18 @@ public class TransportKeyManagerTest extends BriarTestCase {
 		}
 	}
 
-	private static class RunTimerTaskAction implements Action {
+	private static class RunAction implements Action {
 
 		@Override
 		public Object invoke(Invocation invocation) throws Throwable {
-			TimerTask task = (TimerTask) invocation.getParameter(0);
+			Runnable task = (Runnable) invocation.getParameter(0);
 			task.run();
 			return null;
 		}
 
 		@Override
 		public void describeTo(Description description) {
-			description.appendText("schedules a timer task");
+			description.appendText("runs a runnable");
 		}
 	}
 }