Refactored use of the DefaultMessageListener so it's retrieved from the InternalContext

core/src/main/java/ch/dissem/bitmessage/BitmessageContext.java

@@ -62,16 +62,16 @@ public class BitmessageContext {
     private final InternalContext ctx;
 
     private final Labeler labeler;
-    private final NetworkHandler.MessageListener networkListener;
 
     private final boolean sendPubkeyOnIdentityCreation;
 
     private BitmessageContext(Builder builder) {
+        if (builder.listener instanceof Listener.WithContext) {
+            ((Listener.WithContext) builder.listener).setContext(this);
+        }
         ctx = new InternalContext(builder);
         labeler = builder.labeler;
         ctx.getProofOfWorkService().doMissingProofOfWork(30_000); // TODO: this should be configurable
-
-        networkListener = new DefaultMessageListener(ctx, labeler, builder.listener);
         sendPubkeyOnIdentityCreation = builder.sendPubkeyOnIdentityCreation;
     }
 
@@ -180,7 +180,7 @@ public class BitmessageContext {
     }
 
     public void startup() {
-        ctx.getNetworkHandler().start(networkListener);
+        ctx.getNetworkHandler().start();
     }
 
     public void shutdown() {
@@ -195,7 +195,7 @@ public class BitmessageContext {
      * @param wait             waits for the synchronization thread to finish
      */
     public void synchronize(InetAddress host, int port, long timeoutInSeconds, boolean wait) {
-        Future<?> future = ctx.getNetworkHandler().synchronize(host, port, networkListener, timeoutInSeconds);
+        Future<?> future = ctx.getNetworkHandler().synchronize(host, port, timeoutInSeconds);
         if (wait) {
             try {
                 future.get();
@@ -271,7 +271,7 @@ public class BitmessageContext {
                 broadcast.decrypt(address);
                 // This decrypts it twice, but on the other hand it doesn't try to decrypt the objects with
                 // other subscriptions and the interface stays as simple as possible.
-                networkListener.receive(object);
+                ctx.getNetworkListener().receive(object);
             } catch (DecryptionFailedException ignore) {
             } catch (Exception e) {
                 LOG.debug(e.getMessage(), e);
@@ -296,6 +296,13 @@ public class BitmessageContext {
 
     public interface Listener {
         void receive(Plaintext plaintext);
+
+        /**
+         * A message listener that needs a {@link BitmessageContext}, i.e. for implementing some sort of chat bot.
+         */
+        interface WithContext extends Listener {
+            void setContext(BitmessageContext ctx);
+        }
     }
 
     public static final class Builder {

core/src/main/java/ch/dissem/bitmessage/DefaultMessageListener.java

@@ -24,7 +24,6 @@ import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
 import ch.dissem.bitmessage.ports.Labeler;
 import ch.dissem.bitmessage.ports.NetworkHandler;
-import ch.dissem.bitmessage.utils.TTL;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -32,21 +31,24 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
-import static ch.dissem.bitmessage.entity.Plaintext.Status.*;
+import static ch.dissem.bitmessage.entity.Plaintext.Status.PUBKEY_REQUESTED;
-import static ch.dissem.bitmessage.utils.UnixTime.DAY;
 
-class DefaultMessageListener implements NetworkHandler.MessageListener {
+class DefaultMessageListener implements NetworkHandler.MessageListener, InternalContext.ContextHolder {
     private final static Logger LOG = LoggerFactory.getLogger(DefaultMessageListener.class);
-    private final InternalContext ctx;
     private final Labeler labeler;
     private final BitmessageContext.Listener listener;
+    private InternalContext ctx;
 
-    public DefaultMessageListener(InternalContext context, Labeler labeler, BitmessageContext.Listener listener) {
+    public DefaultMessageListener(Labeler labeler, BitmessageContext.Listener listener) {
-        this.ctx = context;
         this.labeler = labeler;
         this.listener = listener;
     }
 
+    @Override
+    public void setContext(InternalContext context) {
+        this.ctx = context;
+    }
+
     @Override
     @SuppressWarnings("ConstantConditions")
     public void receive(ObjectMessage object) throws IOException {

core/src/main/java/ch/dissem/bitmessage/InternalContext.java

@@ -56,6 +56,7 @@ public class InternalContext {
     private final CustomCommandHandler customCommandHandler;
     private final ProofOfWorkService proofOfWorkService;
     private final Labeler labeler;
+    private final NetworkHandler.MessageListener networkListener;
 
     private final TreeSet<Long> streams = new TreeSet<>();
     private final int port;
@@ -79,6 +80,7 @@ public class InternalContext {
         this.connectionLimit = builder.connectionLimit;
         this.connectionTTL = builder.connectionTTL;
         this.labeler = builder.labeler;
+        this.networkListener = new DefaultMessageListener(labeler, builder.listener);
 
         Singleton.initialize(cryptography);
 
@@ -94,7 +96,8 @@ public class InternalContext {
         }
 
         init(cryptography, inventory, nodeRegistry, networkHandler, addressRepository, messageRepository,
-                proofOfWorkRepository, proofOfWorkService, proofOfWorkEngine, customCommandHandler, builder.labeler);
+            proofOfWorkRepository, proofOfWorkService, proofOfWorkEngine, customCommandHandler, builder.labeler,
+            networkListener);
         for (BitmessageAddress identity : addressRepository.getIdentities()) {
             streams.add(identity.getStream());
         }
@@ -148,6 +151,10 @@ public class InternalContext {
         return labeler;
     }
 
+    public NetworkHandler.MessageListener getNetworkListener() {
+        return networkListener;
+    }
+
     public long[] getStreams() {
         long[] result = new long[streams.size()];
         int i = 0;

core/src/main/java/ch/dissem/bitmessage/ProofOfWorkService.java

@@ -11,6 +11,7 @@ import ch.dissem.bitmessage.ports.ProofOfWorkRepository.Item;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
 import java.util.List;
 import java.util.Timer;
 import java.util.TimerTask;
@@ -89,6 +90,11 @@ public class ProofOfWorkService implements ProofOfWorkEngine.Callback, InternalC
                 ctx.getLabeler().markAsSent(plaintext);
                 messageRepo.save(plaintext);
             }
+            try {
+                ctx.getNetworkListener().receive(object);
+            } catch (IOException e) {
+                LOG.debug(e.getMessage(), e);
+            }
             ctx.getInventory().storeObject(object);
             ctx.getNetworkHandler().offer(object.getInventoryVector());
         } else {

core/src/main/java/ch/dissem/bitmessage/ports/NetworkHandler.java

@@ -41,7 +41,7 @@ public interface NetworkHandler {
      * An implementation should disconnect if either the timeout is reached or the returned thread is interrupted.
      * </p>
      */
-    Future<?> synchronize(InetAddress server, int port, MessageListener listener, long timeoutInSeconds);
+    Future<?> synchronize(InetAddress server, int port, long timeoutInSeconds);
 
     /**
      * Send a custom message to a specific node (that should implement handling for this message type) and returns
@@ -57,7 +57,7 @@ public interface NetworkHandler {
     /**
      * Start a full network node, accepting incoming connections and relaying objects.
      */
-    void start(MessageListener listener);
+    void start();
 
     /**
      * Stop the full network node.

core/src/test/java/ch/dissem/bitmessage/DefaultMessageListenerTest.java

@@ -68,7 +68,7 @@ public class DefaultMessageListenerTest extends TestBase {
         when(ctx.getNetworkHandler()).thenReturn(networkHandler);
         when(ctx.getLabeler()).thenReturn(mock(Labeler.class));
 
-        listener = new DefaultMessageListener(ctx, mock(Labeler.class), mock(BitmessageContext.Listener.class));
+        listener = new DefaultMessageListener(mock(Labeler.class), mock(BitmessageContext.Listener.class));
     }
 
     @Test

networking/src/main/java/ch/dissem/bitmessage/networking/AbstractConnection.java

@@ -71,14 +71,13 @@ public abstract class AbstractConnection {
 
     public AbstractConnection(InternalContext context, Mode mode,
                               NetworkAddress node,
-                              NetworkHandler.MessageListener listener,
                               Set<InventoryVector> commonRequestedObjects,
                               long syncTimeout) {
         this.ctx = context;
         this.mode = mode;
         this.host = new NetworkAddress.Builder().ipv6(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0).port(0).build();
         this.node = node;
-        this.listener = listener;
+        this.listener = context.getNetworkListener();
         this.syncTimeout = (syncTimeout > 0 ? UnixTime.now(+syncTimeout) : 0);
         this.requestedObjects = Collections.newSetFromMap(new ConcurrentHashMap<InventoryVector, Boolean>(10_000));
         this.ivCache = new ConcurrentHashMap<>();

networking/src/main/java/ch/dissem/bitmessage/networking/Connection.java

@@ -63,29 +63,29 @@ class Connection extends AbstractConnection {
     private OutputStream out;
     private boolean socketInitialized;
 
-    public Connection(InternalContext context, Mode mode, Socket socket, MessageListener listener,
+    public Connection(InternalContext context, Mode mode, Socket socket,
                       Set<InventoryVector> requestedObjectsMap) throws IOException {
-        this(context, mode, listener, socket, requestedObjectsMap,
+        this(context, mode, socket, requestedObjectsMap,
                 new NetworkAddress.Builder().ip(socket.getInetAddress()).port(socket.getPort()).stream(1).build(),
                 0);
     }
 
-    public Connection(InternalContext context, Mode mode, NetworkAddress node, MessageListener listener,
+    public Connection(InternalContext context, Mode mode, NetworkAddress node,
                       Set<InventoryVector> requestedObjectsMap) {
-        this(context, mode, listener, new Socket(), requestedObjectsMap,
+        this(context, mode, new Socket(), requestedObjectsMap,
                 node, 0);
     }
 
-    private Connection(InternalContext context, Mode mode, MessageListener listener, Socket socket,
+    private Connection(InternalContext context, Mode mode, Socket socket,
                        Set<InventoryVector> commonRequestedObjects, NetworkAddress node, long syncTimeout) {
-        super(context, mode, node, listener, commonRequestedObjects, syncTimeout);
+        super(context, mode, node, commonRequestedObjects, syncTimeout);
         this.startTime = UnixTime.now();
         this.socket = socket;
     }
 
     public static Connection sync(InternalContext ctx, InetAddress address, int port, MessageListener listener,
                                   long timeoutInSeconds) throws IOException {
-        return new Connection(ctx, SYNC, listener, new Socket(address, port),
+        return new Connection(ctx, SYNC, new Socket(address, port),
                 new HashSet<InventoryVector>(),
                 new NetworkAddress.Builder().ip(address).port(port).stream(1).build(),
                 timeoutInSeconds);

networking/src/main/java/ch/dissem/bitmessage/networking/ConnectionOrganizer.java

@@ -42,11 +42,10 @@ public class ConnectionOrganizer implements Runnable {
     private Connection initialConnection;
 
     public ConnectionOrganizer(InternalContext ctx,
-                               DefaultNetworkHandler networkHandler,
+                               DefaultNetworkHandler networkHandler) {
-                               NetworkHandler.MessageListener listener) {
         this.ctx = ctx;
         this.networkHandler = networkHandler;
-        this.listener = listener;
+        this.listener = ctx.getNetworkListener();
     }
 
     @Override
@@ -91,8 +90,7 @@ public class ConnectionOrganizer implements Runnable {
                                 NETWORK_MAGIC_NUMBER - active, ctx.getStreams());
                         boolean first = active == 0 && initialConnection == null;
                         for (NetworkAddress address : addresses) {
-                            Connection c = new Connection(ctx, CLIENT, address, listener,
+                            Connection c = new Connection(ctx, CLIENT, address, networkHandler.requestedObjects);
-                                    networkHandler.requestedObjects);
                             if (first) {
                                 initialConnection = c;
                                 first = false;

networking/src/main/java/ch/dissem/bitmessage/networking/DefaultNetworkHandler.java

@@ -64,9 +64,9 @@ public class DefaultNetworkHandler implements NetworkHandler, ContextHolder {
     }
 
     @Override
-    public Future<?> synchronize(InetAddress server, int port, MessageListener listener, long timeoutInSeconds) {
+    public Future<?> synchronize(InetAddress server, int port, long timeoutInSeconds) {
         try {
-            Connection connection = Connection.sync(ctx, server, port, listener, timeoutInSeconds);
+            Connection connection = Connection.sync(ctx, server, port, ctx.getNetworkListener(), timeoutInSeconds);
             Future<?> reader = pool.submit(connection.getReader());
             pool.execute(connection.getWriter());
             return reader;
@@ -97,19 +97,16 @@ public class DefaultNetworkHandler implements NetworkHandler, ContextHolder {
     }
 
     @Override
-    public void start(final MessageListener listener) {
+    public void start() {
-        if (listener == null) {
-            throw new IllegalStateException("Listener must be set at start");
-        }
         if (running) {
             throw new IllegalStateException("Network already running - you need to stop first.");
         }
         try {
             running = true;
             connections.clear();
-            server = new ServerRunnable(ctx, this, listener);
+            server = new ServerRunnable(ctx, this);
             pool.execute(server);
-            pool.execute(new ConnectionOrganizer(ctx, this, listener));
+            pool.execute(new ConnectionOrganizer(ctx, this));
         } catch (IOException e) {
             throw new ApplicationException(e);
         }

networking/src/main/java/ch/dissem/bitmessage/networking/ServerRunnable.java

@@ -38,11 +38,10 @@ public class ServerRunnable implements Runnable, Closeable {
     private final DefaultNetworkHandler networkHandler;
     private final NetworkHandler.MessageListener listener;
 
-    public ServerRunnable(InternalContext ctx, DefaultNetworkHandler networkHandler,
+    public ServerRunnable(InternalContext ctx, DefaultNetworkHandler networkHandler) throws IOException {
-                          NetworkHandler.MessageListener listener) throws IOException {
         this.ctx = ctx;
         this.networkHandler = networkHandler;
-        this.listener = listener;
+        this.listener = ctx.getNetworkListener();
         this.serverSocket = new ServerSocket(ctx.getPort());
     }
 
@@ -52,8 +51,7 @@ public class ServerRunnable implements Runnable, Closeable {
             try {
                 Socket socket = serverSocket.accept();
                 socket.setSoTimeout(Connection.READ_TIMEOUT);
-                networkHandler.startConnection(new Connection(ctx, SERVER, socket, listener,
+                networkHandler.startConnection(new Connection(ctx, SERVER, socket, networkHandler.requestedObjects));
-                        networkHandler.requestedObjects));
             } catch (IOException e) {
                 LOG.debug(e.getMessage(), e);
             }

networking/src/main/java/ch/dissem/bitmessage/networking/nio/ConnectionInfo.java

@@ -17,13 +17,15 @@
 package ch.dissem.bitmessage.networking.nio;
 
 import ch.dissem.bitmessage.InternalContext;
-import ch.dissem.bitmessage.entity.*;
+import ch.dissem.bitmessage.entity.GetData;
+import ch.dissem.bitmessage.entity.MessagePayload;
+import ch.dissem.bitmessage.entity.NetworkMessage;
+import ch.dissem.bitmessage.entity.Version;
 import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.entity.valueobject.NetworkAddress;
 import ch.dissem.bitmessage.exception.NodeException;
 import ch.dissem.bitmessage.factory.V3MessageReader;
 import ch.dissem.bitmessage.networking.AbstractConnection;
-import ch.dissem.bitmessage.ports.NetworkHandler;
 
 import java.nio.ByteBuffer;
 import java.util.Iterator;
@@ -43,10 +45,9 @@ public class ConnectionInfo extends AbstractConnection {
     private boolean syncFinished;
     private long lastUpdate = System.currentTimeMillis();
 
-    public ConnectionInfo(InternalContext context, Mode mode,
+    public ConnectionInfo(InternalContext context, Mode mode, NetworkAddress node,
-                          NetworkAddress node, NetworkHandler.MessageListener listener,
                           Set<InventoryVector> commonRequestedObjects, long syncTimeout) {
-        super(context, mode, node, listener, commonRequestedObjects, syncTimeout);
+        super(context, mode, node, commonRequestedObjects, syncTimeout);
         headerOut.flip();
         if (mode == CLIENT || mode == SYNC) {
             send(new Version.Builder().defaults(ctx.getClientNonce()).addrFrom(host).addrRecv(node).build());

networking/src/main/java/ch/dissem/bitmessage/networking/nio/NioNetworkHandler.java

@@ -26,7 +26,7 @@ import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.exception.NodeException;
 import ch.dissem.bitmessage.factory.V3MessageReader;
 import ch.dissem.bitmessage.ports.NetworkHandler;
-import ch.dissem.bitmessage.utils.*;
+import ch.dissem.bitmessage.utils.Property;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -37,7 +37,6 @@ import java.net.NoRouteToHostException;
 import java.nio.ByteBuffer;
 import java.nio.channels.*;
 import java.util.*;
-import java.util.Collections;
 import java.util.concurrent.*;
 
 import static ch.dissem.bitmessage.networking.AbstractConnection.Mode.*;
@@ -47,6 +46,7 @@ import static ch.dissem.bitmessage.utils.Collections.selectRandom;
 import static ch.dissem.bitmessage.utils.DebugUtils.inc;
 import static ch.dissem.bitmessage.utils.ThreadFactoryBuilder.pool;
 import static java.nio.channels.SelectionKey.*;
+import static java.util.Collections.newSetFromMap;
 
 /**
  * Network handler using java.nio, resulting in less threads.
@@ -63,13 +63,14 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
     private InternalContext ctx;
     private Selector selector;
     private ServerSocketChannel serverChannel;
+    private Queue<NetworkAddress> connectionQueue = new ConcurrentLinkedQueue<>();
     private Map<ConnectionInfo, SelectionKey> connections = new ConcurrentHashMap<>();
-    private final Set<InventoryVector> requestedObjects = Collections.newSetFromMap(new ConcurrentHashMap<InventoryVector, Boolean>(10_000));
+    private final Set<InventoryVector> requestedObjects = newSetFromMap(new ConcurrentHashMap<InventoryVector, Boolean>(10_000));
 
     private Thread starter;
 
     @Override
-    public Future<Void> synchronize(final InetAddress server, final int port, final MessageListener listener, final long timeoutInSeconds) {
+    public Future<Void> synchronize(final InetAddress server, final int port, final long timeoutInSeconds) {
         return threadPool.submit(new Callable<Void>() {
             @Override
             public Void call() throws Exception {
@@ -77,7 +78,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                     channel.configureBlocking(false);
                     ConnectionInfo connection = new ConnectionInfo(ctx, SYNC,
                         new NetworkAddress.Builder().ip(server).port(port).stream(1).build(),
-                        listener, new HashSet<InventoryVector>(), timeoutInSeconds);
+                        new HashSet<InventoryVector>(), timeoutInSeconds);
                     while (channel.isConnected() && !connection.isSyncFinished()) {
                         write(channel, connection);
                         read(channel, connection);
@@ -135,10 +136,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
     }
 
     @Override
-    public void start(final MessageListener listener) {
+    public void start() {
-        if (listener == null) {
-            throw new IllegalStateException("Listener must be set at start");
-        }
         if (selector != null && selector.isOpen()) {
             throw new IllegalStateException("Network already running - you need to stop first.");
         }
@@ -147,42 +145,8 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
         } catch (IOException e) {
             throw new ApplicationException(e);
         }
-        thread("connection listener", new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    serverChannel = ServerSocketChannel.open();
-                    serverChannel.socket().bind(new InetSocketAddress(ctx.getPort()));
-                    while (selector.isOpen() && serverChannel.isOpen()) {
-                        try {
-                            SocketChannel accepted = serverChannel.accept();
-                            accepted.configureBlocking(false);
-                            ConnectionInfo connection = new ConnectionInfo(ctx, SERVER,
-                                new NetworkAddress.Builder().address(accepted.getRemoteAddress()).stream(1).build(),
-                                listener,
-                                requestedObjects, 0
-                            );
-                            connections.put(
-                                connection,
-                                accepted.register(selector, OP_READ | OP_WRITE, connection)
-                            );
-                        } catch (AsynchronousCloseException ignore) {
-                            LOG.trace(ignore.getMessage());
-                        } catch (IOException e) {
-                            LOG.error(e.getMessage(), e);
-                        }
-                    }
-                } catch (ClosedSelectorException | AsynchronousCloseException ignore) {
-                } catch (IOException e) {
-                    throw new ApplicationException(e);
-                } catch (RuntimeException e) {
-                    e.printStackTrace();
-                    throw e;
-                }
-            }
-        });
 
-        starter = thread("connection starter", new Runnable() {
+        starter = thread("connection manager", new Runnable() {
             @Override
             public void run() {
                 while (selector.isOpen()) {
@@ -197,34 +161,8 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                         List<NetworkAddress> addresses = ctx.getNodeRegistry().getKnownAddresses(100, ctx.getStreams());
                         addresses = selectRandom(missing, addresses);
                         for (NetworkAddress address : addresses) {
-                            if (isConnectedTo(address)) {
+                            if (!isConnectedTo(address)) {
-                                continue;
+                                connectionQueue.offer(address);
-                            }
-                            try {
-                                SocketChannel channel = SocketChannel.open();
-                                channel.configureBlocking(false);
-                                channel.connect(new InetSocketAddress(address.toInetAddress(), address.getPort()));
-                                ConnectionInfo connection = new ConnectionInfo(ctx, CLIENT,
-                                    address,
-                                    listener,
-                                    requestedObjects, 0
-                                );
-                                connections.put(
-                                    connection,
-                                    channel.register(selector, OP_CONNECT, connection)
-                                );
-                            } catch (NoRouteToHostException ignore) {
-                                // We'll try to connect to many offline nodes, so
-                                // this is expected to happen quite a lot.
-                            } catch (AsynchronousCloseException e) {
-                                // The exception is expected if the network is being
-                                // shut down, as we actually do asynchronously close
-                                // the connections.
-                                if (isRunning()) {
-                                    LOG.error(e.getMessage(), e);
-                                }
-                            } catch (IOException e) {
-                                LOG.error(e.getMessage(), e);
                             }
                         }
                     }
@@ -252,17 +190,47 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
             }
         });
 
-        thread("processor", new Runnable() {
+        thread("selector worker", new Runnable() {
             @Override
             public void run() {
                 try {
+                    serverChannel = ServerSocketChannel.open();
+                    serverChannel.configureBlocking(false);
+                    serverChannel.socket().bind(new InetSocketAddress(ctx.getPort()));
+                    serverChannel.register(selector, OP_ACCEPT, null);
+
                     while (selector.isOpen()) {
                         selector.select(1000);
                         Iterator<SelectionKey> keyIterator = selector.selectedKeys().iterator();
                         while (keyIterator.hasNext()) {
                             SelectionKey key = keyIterator.next();
                             keyIterator.remove();
-                            if (key.attachment() instanceof ConnectionInfo) {
+                            if (key.attachment() == null) {
+                                try {
+                                    if (key.isAcceptable()) {
+                                        // handle accept
+                                        try {
+                                            SocketChannel accepted = ((ServerSocketChannel) key.channel()).accept();
+                                            accepted.configureBlocking(false);
+                                            ConnectionInfo connection = new ConnectionInfo(ctx, SERVER,
+                                                new NetworkAddress.Builder().address(accepted.getRemoteAddress()).stream(1).build(),
+                                                requestedObjects, 0
+                                            );
+                                            connections.put(
+                                                connection,
+                                                accepted.register(selector, OP_READ | OP_WRITE, connection)
+                                            );
+                                        } catch (AsynchronousCloseException e) {
+                                            LOG.trace(e.getMessage());
+                                        } catch (IOException e) {
+                                            LOG.error(e.getMessage(), e);
+                                        }
+                                    }
+                                } catch (CancelledKeyException e) {
+                                    LOG.error(e.getMessage(), e);
+                                }
+                            } else {
+                                // handle read/write
                                 SocketChannel channel = (SocketChannel) key.channel();
                                 ConnectionInfo connection = (ConnectionInfo) key.attachment();
                                 try {
@@ -290,6 +258,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                                 }
                             }
                         }
+                        // set interest ops
                         for (Map.Entry<ConnectionInfo, SelectionKey> e : connections.entrySet()) {
                             if (e.getValue().isValid()
                                 && (e.getValue().interestOps() & OP_WRITE) == 0
@@ -298,6 +267,35 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                                 e.getValue().interestOps(OP_READ | OP_WRITE);
                             }
                         }
+                        // start new connections
+                        if (!connectionQueue.isEmpty()) {
+                            NetworkAddress address = connectionQueue.poll();
+                            try {
+                                SocketChannel channel = SocketChannel.open();
+                                channel.configureBlocking(false);
+                                channel.connect(new InetSocketAddress(address.toInetAddress(), address.getPort()));
+                                ConnectionInfo connection = new ConnectionInfo(ctx, CLIENT,
+                                    address,
+                                    requestedObjects, 0
+                                );
+                                connections.put(
+                                    connection,
+                                    channel.register(selector, OP_CONNECT, connection)
+                                );
+                            } catch (NoRouteToHostException ignore) {
+                                // We'll try to connect to many offline nodes, so
+                                // this is expected to happen quite a lot.
+                            } catch (AsynchronousCloseException e) {
+                                // The exception is expected if the network is being
+                                // shut down, as we actually do asynchronously close
+                                // the connections.
+                                if (isRunning()) {
+                                    LOG.error(e.getMessage(), e);
+                                }
+                            } catch (IOException e) {
+                                LOG.error(e.getMessage(), e);
+                            }
+                        }
                     }
                     selector.close();
                 } catch (ClosedSelectorException ignore) {

networking/src/test/java/ch/dissem/bitmessage/networking/NetworkHandlerTest.java

@@ -230,9 +230,7 @@ public class NetworkHandlerTest {
             "V4Pubkey.payload"
         );
 
-        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(),
+        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(), 10);
-            mock(NetworkHandler.MessageListener.class),
-            10);
         future.get();
         assertInventorySize(3, nodeInventory);
         assertInventorySize(3, peerInventory);
@@ -247,9 +245,7 @@ public class NetworkHandlerTest {
 
         nodeInventory.init();
 
-        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(),
+        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(), 10);
-            mock(NetworkHandler.MessageListener.class),
-            10);
         future.get();
         assertInventorySize(2, nodeInventory);
         assertInventorySize(2, peerInventory);
@@ -263,9 +259,7 @@ public class NetworkHandlerTest {
             "V1Msg.payload"
         );
 
-        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(),
+        Future<?> future = nodeNetworkHandler.synchronize(peerAddress.toInetAddress(), peerAddress.getPort(), 10);
-            mock(NetworkHandler.MessageListener.class),
-            10);
         future.get();
         assertInventorySize(1, nodeInventory);
         assertInventorySize(1, peerInventory);

repositories/src/main/java/ch/dissem/bitmessage/repository/JdbcNodeRegistry.java

@@ -105,7 +105,7 @@ public class JdbcNodeRegistry extends JdbcHelper implements NodeRegistry {
             }
             for (long stream : streams) {
                 Set<NetworkAddress> nodes = stableNodes.get(stream);
-                if (nodes != null) {
+                if (nodes != null && !nodes.isEmpty()) {
                     result.add(Collections.selectRandom(nodes));
                 }
             }