Reduce DB queries for looking up transport properties.

bramble-core/src/main/java/org/briarproject/bramble/plugin/PluginManagerImpl.java

@@ -283,6 +283,16 @@ class PluginManagerImpl implements PluginManager, Service {
 			}
 		}
 
+		@Override
+		public TransportProperties getRemoteProperties(ContactId c) {
+			try {
+				return transportPropertyManager.getRemoteProperties(c, id);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return new TransportProperties();
+			}
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 			try {

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/TcpPlugin.java

@@ -25,6 +25,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -209,8 +210,9 @@ abstract class TcpPlugin implements DuplexPlugin {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		for (Entry<ContactId, TransportProperties> e :
-				callback.getRemoteProperties().entrySet()) {
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
 			ContactId c = e.getKey();
 			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
 		}
@@ -234,8 +236,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
-		return p == null ? null : createConnection(p);
+		return createConnection(callback.getRemoteProperties(c));
 	}
 
 	@Nullable

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

@@ -160,35 +160,52 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
+		Map<ContactId, TransportProperties> remote =
+				new HashMap<ContactId, TransportProperties>();
+		Transaction txn = db.startTransaction(true);
 		try {
-			Map<ContactId, TransportProperties> remote =
-					new HashMap<ContactId, TransportProperties>();
-			Transaction txn = db.startTransaction(true);
-			try {
-				for (Contact c : db.getContacts(txn)) {
-					// Don't return properties for inactive contacts
-					if (!c.isActive()) continue;
-					Group g = getContactGroup(c);
-					// Find the latest remote update
-					LatestUpdate latest = findLatest(txn, g.getId(), t, false);
-					if (latest != null) {
-						// Retrieve and parse the latest remote properties
-						BdfList message = clientHelper.getMessageAsList(txn,
-								latest.messageId);
-						if (message == null) throw new DbException();
-						remote.put(c.getId(), parseProperties(message));
-					}
-				}
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
-			return remote;
+			for (Contact c : db.getContacts(txn))
+				remote.put(c.getId(), getRemoteProperties(txn, c, t));
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return remote;
+	}
+
+	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
+			TransportId t) throws DbException {
+		// Don't return properties for inactive contacts
+		if (!c.isActive()) return new TransportProperties();
+		Group g = getContactGroup(c);
+		try {
+			// Find the latest remote update
+			LatestUpdate latest = findLatest(txn, g.getId(), t, false);
+			if (latest == null) return new TransportProperties();
+			// Retrieve and parse the latest remote properties
+			BdfList message =
+					clientHelper.getMessageAsList(txn, latest.messageId);
+			if (message == null) throw new DbException();
+			return parseProperties(message);
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}
 	}
 
+	@Override
+	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
+			throws DbException {
+		TransportProperties p;
+		Transaction txn = db.startTransaction(true);
+		try {
+			p = getRemoteProperties(txn, db.getContact(txn, c), t);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return p;
+	}
+
 	@Override
 	public void mergeLocalProperties(TransportId t, TransportProperties p)
 			throws DbException {

bramble-core/src/test/java/org/briarproject/bramble/plugin/tcp/LanTcpPluginTest.java

@@ -311,6 +311,11 @@ public class LanTcpPluginTest extends BrambleTestCase {
 			return remote;
 		}
 
+		@Override
+		public TransportProperties getRemoteProperties(ContactId c) {
+			return remote.get(c);
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 		}