Much work on generalizing the notion of message "transport" and

allowing the use of annotations to customize transport for 
DObject fields and service/receiver methods.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5099 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/annotation/TransportHint.java

@@ -0,0 +1,44 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2008 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.presents.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import com.threerings.presents.net.Transport;
+
+/**
+ * An annotation indicating the type of transport desired for a distributed object
+ * class, field, or method.
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD, ElementType.TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface TransportHint
+{
+    /** The type of transport to use. */
+    Transport.Type type () default Transport.Type.RELIABLE_ORDERED;
+
+    /** For ordered transport types, the channel to use. */
+    int channel () default 0;
+}

src/java/com/threerings/presents/client/BlockingCommunicator.java

@@ -61,6 +61,7 @@ import com.threerings.presents.net.DownstreamMessage;
 import com.threerings.presents.net.LogoffRequest;
 import com.threerings.presents.net.PingRequest;
 import com.threerings.presents.net.PongResponse;
+import com.threerings.presents.net.Transport;
 import com.threerings.presents.net.UpstreamMessage;
 import com.threerings.presents.util.DatagramSequencer;
 
@@ -163,7 +164,7 @@ public class BlockingCommunicator extends Communicator
     public void postMessage (UpstreamMessage msg)
     {
         // post as datagram if hinted and possible
-        if (msg.datagram && _datagramWriter != null) {
+        if (!msg.getTransport().isReliable() && _datagramWriter != null) {
             _dataq.append(msg);
         } else {
             _msgq.append(msg);
@@ -486,6 +487,7 @@ public class BlockingCommunicator extends Communicator
         if (_datagramChannel.read(_buf) <= 0) {
             throw new IOException("No datagram available to read.");
         }
+        _buf.flip();
 
         // decode through the sequencer
         try {
@@ -493,7 +495,6 @@ public class BlockingCommunicator extends Communicator
             if (msg == null) {
                 return null; // received out of order
             }
-            msg.datagram = true;
             if (debugLogMessages()) {
                 Log.info("DATAGRAM " + msg);
             }
@@ -802,7 +803,7 @@ public class BlockingCommunicator extends Communicator
             _datagramChannel.connect(new InetSocketAddress(_client.getHostname(), port));
             for (int ii = 0; ii < DATAGRAM_ATTEMPTS_PER_PORT; ii++) {
                 // send a ping datagram
-                sendDatagram(new PingRequest());
+                sendDatagram(new PingRequest(Transport.UNRELIABLE_UNORDERED));
 
                 // wait for a response
                 int resp = _selector.select(DATAGRAM_RESPONSE_WAIT);

src/java/com/threerings/presents/client/InvocationDirector.java

@@ -45,6 +45,8 @@ import com.threerings.presents.dobj.MessageEvent;
 import com.threerings.presents.dobj.ObjectAccessException;
 import com.threerings.presents.dobj.Subscriber;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Handles the client side management of the invocation services.
  */
@@ -195,6 +197,16 @@ public class InvocationDirector
      * invocation oid.
      */
     public void sendRequest (int invOid, int invCode, int methodId, Object[] args)
+    {
+        sendRequest(invOid, invCode, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Requests that the specified invocation request be packaged up and sent to the supplied
+     * invocation oid.
+     */
+    public void sendRequest (
+        int invOid, int invCode, int methodId, Object[] args, Transport transport)
     {
         if (_clobj == null) {
             Log.warning("Dropping invocation request on shutdown director [code=" + invCode +
@@ -218,7 +230,8 @@ public class InvocationDirector
         }
 
         // create an invocation request event
-        InvocationRequestEvent event = new InvocationRequestEvent(invOid, invCode, methodId, args);
+        InvocationRequestEvent event =
+            new InvocationRequestEvent(invOid, invCode, methodId, args, transport);
 
         // because invocation directors are used on the server, we set the source oid here so that
         // invocation requests are properly attributed to the right client object when created by

src/java/com/threerings/presents/data/InvocationMarshaller.java

@@ -35,6 +35,8 @@ import com.threerings.presents.client.InvocationService;
 import com.threerings.presents.dobj.DObjectManager;
 import com.threerings.presents.dobj.InvocationResponseEvent;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Provides a base from which all invocation service marshallers extend.  Handles functionality
  * common to all marshallers.
@@ -69,6 +71,10 @@ public class InvocationMarshaller
          * valid on the server. */
         public transient DObjectManager omgr;
 
+        /** The transport mode through which the request was received.  This is only valid on the
+         * server. */
+        public transient Transport transport;
+
         /**
          * Set an identifier for the invocation that this listener is used for, so we can report it
          * if we are never responded-to.
@@ -92,7 +98,7 @@ public class InvocationMarshaller
         {
             _invId = null;
             omgr.postEvent(new InvocationResponseEvent(
-                               callerOid, requestId, REQUEST_FAILED_RSPID, new Object[] { cause }));
+                callerOid, requestId, REQUEST_FAILED_RSPID, new Object[] { cause }, transport));
         }
 
         /**
@@ -130,7 +136,7 @@ public class InvocationMarshaller
         }
 
         /** On the server, the id of the invocation method. */
-        protected transient String _invId; 
+        protected transient String _invId;
     }
 
     /**
@@ -146,8 +152,8 @@ public class InvocationMarshaller
         public void requestProcessed ()
         {
             _invId = null;
-            omgr.postEvent(
+            omgr.postEvent(new InvocationResponseEvent(
-                new InvocationResponseEvent(callerOid, requestId, REQUEST_PROCESSED, null));
+                callerOid, requestId, REQUEST_PROCESSED, null, transport));
         }
 
         // documentation inherited
@@ -178,7 +184,7 @@ public class InvocationMarshaller
         {
             _invId = null;
             omgr.postEvent(new InvocationResponseEvent(
-                               callerOid, requestId, REQUEST_PROCESSED, new Object[] { result }));
+                callerOid, requestId, REQUEST_PROCESSED, new Object[] { result }, transport));
         }
 
         // documentation inherited
@@ -248,7 +254,16 @@ public class InvocationMarshaller
      */
     protected void sendRequest (Client client, int methodId, Object[] args)
     {
-        client.getInvocationDirector().sendRequest(_invOid, _invCode, methodId, args);
+        sendRequest(client, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Called by generated invocation marshaller code; packages up and sends the specified
+     * invocation service request.
+     */
+    protected void sendRequest (Client client, int methodId, Object[] args, Transport transport)
+    {
+        client.getInvocationDirector().sendRequest(_invOid, _invCode, methodId, args, transport);
     }
 
     /** The oid of the invocation object, where invocation service requests are sent. */

src/java/com/threerings/presents/dobj/AttributeChangedEvent.java

@@ -27,6 +27,8 @@ import java.util.HashMap;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * An attribute changed event is dispatched when a single attribute of a distributed object has
  * changed. It can also be constructed to request an attribute change on an object and posted to
@@ -162,7 +164,24 @@ public class AttributeChangedEvent extends NamedEvent
      */
     protected AttributeChangedEvent (int targetOid, String name, Object value, Object oldValue)
     {
-        super(targetOid, name);
+        this(targetOid, name, value, oldValue, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new attribute changed event on the specified target object with the supplied
+     * attribute name and value. <em>Do not construct these objects by hand.</em> Use {@link
+     * DObject#changeAttribute} instead.
+     *
+     * @param targetOid the object id of the object whose attribute has changed.
+     * @param name the name of the attribute (data member) that has changed.
+     * @param value the new value of the attribute (in the case of primitive types, the
+     * reflection-defined object-alternative is used).
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    protected AttributeChangedEvent (
+        int targetOid, String name, Object value, Object oldValue, Transport transport)
+    {
+        super(targetOid, name, transport);
         _value = value;
         _oldValue = oldValue;
     }

src/java/com/threerings/presents/dobj/CompoundEvent.java

@@ -25,6 +25,8 @@ import java.util.List;
 
 import com.threerings.util.StreamableArrayList;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Used to manage and submit groups of events on a collection of
  * distributed objects in a single transaction.
@@ -91,13 +93,18 @@ public class CompoundEvent extends DEvent
 
         // then post this event onto the queue (but only if we actually
         // accumulated some events)
-        switch (_events.size()) {
+        int size = _events.size();
+        switch (size) {
         case 0: // nothing doing
             break;
         case 1: // no point in being compound
             _omgr.postEvent(_events.get(0));
             break;
         default: // now we're talking
+            _transport = _events.get(0).getTransport();
+            for (int ii = 1; ii < size; ii++) {
+                _transport = _events.get(ii).getTransport().combine(_transport);
+            }
             _omgr.postEvent(this);
             break;
         }
@@ -139,6 +146,15 @@ public class CompoundEvent extends DEvent
         }
     }
 
+    @Override // from DEvent
+    public void setTransport (Transport transport)
+    {
+        super.setTransport(transport);
+        for (int ii = 0, nn = _events.size(); ii < nn; ii++) {
+            _events.get(ii).setTransport(transport);
+        }
+    }
+
     @Override // from DEvent
     public boolean applyToObject (DObject target)
         throws ObjectAccessException

src/java/com/threerings/presents/dobj/DEvent.java

@@ -23,6 +23,8 @@ package com.threerings.presents.dobj;
 
 import com.threerings.io.Streamable;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * A distributed object event is dispatched whenever any modification is made to a distributed
  * object. It can also be dispatched purely for notification purposes, without making any
@@ -45,8 +47,19 @@ public abstract class DEvent implements Streamable
      * Constructs a new distributed object event that pertains to the specified distributed object.
      */
     public DEvent (int targetOid)
+    {
+        this(targetOid, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new distributed object event that pertains to the specified distributed object.
+     *
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public DEvent (int targetOid, Transport transport)
     {
         _toid = targetOid;
+        _transport = transport;
     }
 
     /**
@@ -121,6 +134,24 @@ public abstract class DEvent implements Streamable
         _soid = sourceOid;
     }
 
+    /**
+     * Sets the transport parameters.  For events received over the network, these indicate the
+     * mode of transport over which the event was received.  When an event is sent over the
+     * network, these act as a hint as to the type of transport desired.
+     */
+    public void setTransport (Transport transport)
+    {
+        _transport = transport;
+    }
+
+    /**
+     * Returns the transport parameters.
+     */
+    public Transport getTransport ()
+    {
+        return _transport;
+    }
+
     /**
      * Events with associated listener interfaces should implement this function and notify the
      * supplied listener if it implements their event listening interface. For example, the {@link
@@ -152,6 +183,9 @@ public abstract class DEvent implements Streamable
     {
         buf.append("targetOid=").append(_toid);
         buf.append(", sourceOid=").append(_soid);
+        if (_transport != Transport.DEFAULT) {
+            buf.append(", transport=").append(_transport);
+        }
     }
 
     /** The oid of the object that is the target of this event. */
@@ -160,6 +194,9 @@ public abstract class DEvent implements Streamable
     /** The oid of the client that generated this event. */
     protected transient int _soid = -1;
 
+    /** The transport parameters. */
+    protected transient Transport _transport = Transport.DEFAULT;
+
     /** Used to differentiate between null meaning we haven't initialized our old value and null
      * being the actual old value. */
     protected static final Object UNSET_OLD_VALUE = new Object();

src/java/com/threerings/presents/dobj/DObject.java

@@ -37,6 +37,7 @@ import com.threerings.io.Streamable;
 import com.threerings.util.TrackedObject;
 
 import com.threerings.presents.Log;
+import com.threerings.presents.net.Transport;
 
 /**
  * The distributed object forms the foundation of the Presents system. All information shared among
@@ -250,7 +251,7 @@ public class DObject
     public void setAccessController (AccessController controller)
     {
         _controller = controller;
-    }        
+    }
 
     /**
      * Returns a reference to the access controller in use by this object or null if none has been
@@ -524,11 +525,21 @@ public class DObject
     }
 
     /**
-     * Posts a message event on this distrubuted object.
+     * Posts a message event on this distributed object.
      */
     public void postMessage (String name, Object... args)
     {
-        postEvent(new MessageEvent(_oid, name, args));
+        postMessage(Transport.DEFAULT, name, args);
+    }
+
+    /**
+     * Posts a message event on this distributed object.
+     *
+     * @param transport a hint as to the type of transport desired for the message.
+     */
+    public void postMessage (Transport transport, String name, Object... args)
+    {
+        postEvent(new MessageEvent(_oid, name, args, transport));
     }
 
     /**
@@ -683,7 +694,7 @@ public class DObject
                 _tevent.commit();
             }
         }
-    }        
+    }
 
     /**
      * Returns true if this object is in the middle of a transaction or false if it is not.
@@ -714,7 +725,7 @@ public class DObject
         } else {
             _tevent.cancel();
         }
-    }        
+    }
 
     /**
      * Removes this object from participation in any transaction in which it might be taking part.
@@ -736,19 +747,37 @@ public class DObject
      * Called by derived instances when an attribute setter method was called.
      */
     protected void requestAttributeChange (String name, Object value, Object oldValue)
+    {
+        requestAttributeChange(name, value, oldValue, Transport.DEFAULT);
+    }
+
+    /**
+     * Called by derived instances when an attribute setter method was called.
+     */
+    protected void requestAttributeChange (
+        String name, Object value, Object oldValue, Transport transport)
     {
         // dispatch an attribute changed event
-        postEvent(new AttributeChangedEvent(_oid, name, value, oldValue));
+        postEvent(new AttributeChangedEvent(_oid, name, value, oldValue, transport));
     }
 
     /**
      * Called by derived instances when an element updater method was called.
      */
     protected void requestElementUpdate (String name, int index, Object value, Object oldValue)
+    {
+        requestElementUpdate(name, index, value, oldValue, Transport.DEFAULT);
+    }
+
+    /**
+     * Called by derived instances when an element updater method was called.
+     */
+    protected void requestElementUpdate (
+        String name, int index, Object value, Object oldValue, Transport transport)
     {
         // dispatch an attribute changed event
         postEvent(new ElementUpdatedEvent(
-                      _oid, name, value, oldValue, index));
+                      _oid, name, value, oldValue, index, transport));
     }
 
     /**
@@ -810,6 +839,15 @@ public class DObject
      * Calls by derived instances when a set updater method was called.
      */
     protected <T extends DSet.Entry> void requestEntryUpdate (String name, DSet<T> set, T entry)
+    {
+        requestEntryUpdate(name, set, entry, Transport.DEFAULT);
+    }
+
+    /**
+     * Calls by derived instances when a set updater method was called.
+     */
+    protected <T extends DSet.Entry> void requestEntryUpdate (
+        String name, DSet<T> set, T entry, Transport transport)
     {
         // if we're on the authoritative server, we update the set immediately
         T oldEntry = null;
@@ -820,7 +858,7 @@ public class DObject
             }
         }
         // dispatch an entry updated event
-        postEvent(new EntryUpdatedEvent<T>(_oid, name, entry, oldEntry));
+        postEvent(new EntryUpdatedEvent<T>(_oid, name, entry, oldEntry, transport));
     }
 
     /**

src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java

@@ -26,6 +26,8 @@ import java.lang.reflect.Field;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * An element updated event is dispatched when an element of an array field in a distributed object
  * is updated. It can also be constructed to request the update of an entry and posted to the
@@ -49,7 +51,26 @@ public class ElementUpdatedEvent extends NamedEvent
      */
     public ElementUpdatedEvent (int targetOid, String name, Object value, Object ovalue, int index)
     {
-        super(targetOid, name);
+        this(targetOid, name, value, ovalue, index, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new element updated event on the specified target object with the supplied
+     * attribute name, element and index.
+     *
+     * @param targetOid the object id of the object whose attribute has changed.
+     * @param name the name of the attribute (data member) for which an element has changed.
+     * @param value the new value of the element (in the case of primitive types, the
+     * reflection-defined object-alternative is used).
+     * @param oldValue the previous value of the element (in the case of primitive types, the
+     * reflection-defined object-alternative is used).
+     * @param index the index in the array of the updated element.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public ElementUpdatedEvent (
+        int targetOid, String name, Object value, Object ovalue, int index, Transport transport)
+    {
+        super(targetOid, name, transport);
         _value = value;
         _oldValue = ovalue;
         _index = index;

src/java/com/threerings/presents/dobj/EntryAddedEvent.java

@@ -95,7 +95,8 @@ public class EntryAddedEvent<T extends DSet.Entry> extends NamedEvent
     protected void notifyListener (Object listener)
     {
         if (listener instanceof SetListener) {
-            ((SetListener)listener).entryAdded(this);
+            @SuppressWarnings("unchecked") SetListener<T> setlist = (SetListener<T>)listener;
+            setlist.entryAdded(this);
         }
     }
 

src/java/com/threerings/presents/dobj/EntryRemovedEvent.java

@@ -99,7 +99,8 @@ public class EntryRemovedEvent<T extends DSet.Entry> extends NamedEvent
     protected void notifyListener (Object listener)
     {
         if (listener instanceof SetListener) {
-            ((SetListener)listener).entryRemoved(this);
+            @SuppressWarnings("unchecked") SetListener<T> setlist = (SetListener<T>)listener;
+            setlist.entryRemoved(this);
         }
     }
 

src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java

@@ -25,6 +25,8 @@ import com.samskivert.util.StringUtil;
 
 import com.threerings.presents.Log;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * An entry updated event is dispatched when an entry of a {@link DSet} is updated. It can also be
  * constructed to request the update of an entry and posted to the dobjmgr.
@@ -44,7 +46,22 @@ public class EntryUpdatedEvent<T extends DSet.Entry> extends NamedEvent
      */
     public EntryUpdatedEvent (int targetOid, String name, T entry, T oldEntry)
     {
-        super(targetOid, name);
+        this(targetOid, name, entry, oldEntry, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new entry updated event on the specified target object for the specified set
+     * name and with the supplied updated entry.
+     *
+     * @param targetOid the object id of the object to whose set we will add an entry.
+     * @param name the name of the attribute in which to update the specified entry.
+     * @param entry the entry to update.
+     * @param oldEntry the previous value of the entry.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public EntryUpdatedEvent (int targetOid, String name, T entry, T oldEntry, Transport transport)
+    {
+        super(targetOid, name, transport);
         _entry = entry;
         _oldEntry = oldEntry;
     }
@@ -101,7 +118,8 @@ public class EntryUpdatedEvent<T extends DSet.Entry> extends NamedEvent
     protected void notifyListener (Object listener)
     {
         if (listener instanceof SetListener) {
-            ((SetListener)listener).entryUpdated(this);
+            @SuppressWarnings("unchecked") SetListener<T> setlist = (SetListener<T>)listener;
+            setlist.entryUpdated(this);
         }
     }
 

src/java/com/threerings/presents/dobj/InvocationNotificationEvent.java

@@ -23,6 +23,8 @@ package com.threerings.presents.dobj;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Used to dispatch an invocation notification from the server to a
  * client.
@@ -47,7 +49,27 @@ public class InvocationNotificationEvent extends DEvent
     public InvocationNotificationEvent (
         int targetOid, short receiverId, int methodId, Object[] args)
     {
-        super(targetOid);
+        this(targetOid, receiverId, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new invocation notification event on the specified
+     * target object with the supplied receiver id, method id and
+     * arguments.
+     *
+     * @param targetOid the object id of the object on which the event is
+     * to be dispatched.
+     * @param receiverId identifies the receiver to which this notification
+     * is being dispatched.
+     * @param methodId the id of the method to be invoked.
+     * @param args the arguments for the method. This array should contain
+     * only values of valid distributed object types.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public InvocationNotificationEvent (
+        int targetOid, short receiverId, int methodId, Object[] args, Transport transport)
+    {
+        super(targetOid, transport);
         _receiverId = receiverId;
         _methodId = (byte)methodId;
         _args = args;

src/java/com/threerings/presents/dobj/InvocationRequestEvent.java

@@ -23,6 +23,8 @@ package com.threerings.presents.dobj;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Used to dispatch an invocation request from the client to the server.
  *
@@ -44,7 +46,25 @@ public class InvocationRequestEvent extends DEvent
     public InvocationRequestEvent (
         int targetOid, int invCode, int methodId, Object[] args)
     {
-        super(targetOid);
+        this(targetOid, invCode, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new invocation request event on the specified target
+     * object with the supplied code, method and arguments.
+     *
+     * @param targetOid the object id of the object on which the event is
+     * to be dispatched.
+     * @param invCode the invocation provider identification code.
+     * @param methodId the id of the method to be invoked.
+     * @param args the arguments for the method. This array should contain
+     * only values of valid distributed object types.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public InvocationRequestEvent (
+        int targetOid, int invCode, int methodId, Object[] args, Transport transport)
+    {
+        super(targetOid, transport);
         _invCode = invCode;
         _methodId = (byte)methodId;
         _args = args;

src/java/com/threerings/presents/dobj/InvocationResponseEvent.java

@@ -23,6 +23,8 @@ package com.threerings.presents.dobj;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Used to dispatch an invocation response from the server to the client.
  *
@@ -44,7 +46,25 @@ public class InvocationResponseEvent extends DEvent
     public InvocationResponseEvent (
         int targetOid, int requestId, int methodId, Object[] args)
     {
-        super(targetOid);
+        this(targetOid, requestId, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new invocation response event on the specified target
+     * object with the supplied code, method and arguments.
+     *
+     * @param targetOid the object id of the object on which the event is
+     * to be dispatched.
+     * @param requestId the id of the request to which we are responding.
+     * @param methodId the method to be invoked.
+     * @param args the arguments for the method. This array should contain
+     * only values of valid distributed object types.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public InvocationResponseEvent (
+        int targetOid, int requestId, int methodId, Object[] args, Transport transport)
+    {
+        super(targetOid, transport);
         _requestId = (short)requestId;
         _methodId = (byte)methodId;
         _args = args;

src/java/com/threerings/presents/dobj/MessageEvent.java

@@ -23,6 +23,8 @@ package com.threerings.presents.dobj;
 
 import com.samskivert.util.StringUtil;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * A message event is used to dispatch a message to all subscribers of a
  * distributed object without actually changing any of the fields of the
@@ -46,7 +48,23 @@ public class MessageEvent extends NamedEvent
      */
     public MessageEvent (int targetOid, String name, Object[] args)
     {
-        super(targetOid, name);
+        this(targetOid, name, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new message event on the specified target object with
+     * the supplied name and arguments.
+     *
+     * @param targetOid the object id of the object whose attribute has
+     * changed.
+     * @param name the name of the message event.
+     * @param args the arguments for this message. This array should
+     * contain only values of valid distributed object types.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public MessageEvent (int targetOid, String name, Object[] args, Transport transport)
+    {
+        super(targetOid, name, transport);
         _args = args;
     }
 

src/java/com/threerings/presents/dobj/NamedEvent.java

@@ -21,6 +21,8 @@
 
 package com.threerings.presents.dobj;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * A common parent class for all events that are associated with a name
  * (in some cases a field name, in other cases just an identifying name).
@@ -36,7 +38,20 @@ public abstract class NamedEvent extends DEvent
      */
     public NamedEvent (int targetOid, String name)
     {
-        super(targetOid);
+        this(targetOid, name, Transport.DEFAULT);
+    }
+
+    /**
+     * Constructs a new named event for the specified target object with
+     * the supplied attribute name.
+     *
+     * @param targetOid the object id of the object in question.
+     * @param name the name associated with this event.
+     * @param transport a hint as to the type of transport desired for the event.
+     */
+    public NamedEvent (int targetOid, String name, Transport transport)
+    {
+        super(targetOid, transport);
         _name = name;
     }
 

src/java/com/threerings/presents/net/DownstreamMessage.java

@@ -21,14 +21,12 @@
 
 package com.threerings.presents.net;
 
-import com.threerings.io.SimpleStreamableObject;
-
 /**
  * This class encapsulates a message in the distributed object protocol
  * that flows from the server to the client. Downstream messages include
  * object subscription, event forwarding and session management.
  */
-public abstract class DownstreamMessage extends SimpleStreamableObject
+public abstract class DownstreamMessage extends Message
 {
     /**
      * The message id of the upstream message with which this downstream
@@ -37,12 +35,6 @@ public abstract class DownstreamMessage extends SimpleStreamableObject
      */
     public short messageId = -1;
 
-    /**
-     * When sending, this acts as a hint that the message may be transmitted as a datagram.
-     * When receiving, it indicates that the message was received as a datagram.
-     */
-    public transient boolean datagram;
-
     /**
      * Generates a string representation of this instance.
      */

src/java/com/threerings/presents/net/EventNotification.java

@@ -46,6 +46,19 @@ public class EventNotification extends DownstreamMessage
         return _event;
     }
 
+    @Override // documentation inherited
+    public void setTransport (Transport transport)
+    {
+        // the event handles the transport
+        _event.setTransport(transport);
+    }
+
+    @Override // documentation inherited
+    public Transport getTransport ()
+    {
+        return _event.getTransport();
+    }
+
     public String toString ()
     {
         return "[type=EVT, evt=" + _event + "]";

src/java/com/threerings/presents/net/ForwardEventRequest.java

@@ -49,6 +49,19 @@ public class ForwardEventRequest extends UpstreamMessage
         return _event;
     }
 
+    @Override // documentation inherited
+    public void setTransport (Transport transport)
+    {
+        // the event handles the transport
+        _event.setTransport(transport);
+    }
+
+    @Override // documentation inherited
+    public Transport getTransport ()
+    {
+        return _event.getTransport();
+    }
+
     public String toString ()
     {
         return "[type=FWD, evt=" + _event + "]";

src/java/com/threerings/presents/net/Message.java

@@ -0,0 +1,50 @@
+//
+// $Id: DownstreamMessage.java 5090 2008-05-13 21:12:39Z andrzej $
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2007 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.presents.net;
+
+import com.threerings.io.SimpleStreamableObject;
+
+/**
+ * The superclass of {@link UpstreamMessage} and {@link DownstreamMessage}.
+ */
+public abstract class Message extends SimpleStreamableObject
+{
+    /**
+     * Sets the message transport parameters.  For messages received over the network, these
+     * describe the mode of transport over which the message was received.  When sending messages,
+     * they act as a hint as to the type of transport desired.  Calling this method may have no
+     * effect, depending on whether non-default modes of transport are supported for this message
+     * type.
+     */
+    public void setTransport (Transport transport)
+    {
+        // no-op by default
+    }
+
+    /**
+     * Returns the message transport parameters.
+     */
+    public Transport getTransport ()
+    {
+        return Transport.DEFAULT;
+    }
+}

src/java/com/threerings/presents/net/PingRequest.java

@@ -41,6 +41,14 @@ public class PingRequest extends UpstreamMessage
         super();
     }
 
+    /**
+     * Creates a new ping request using the specified transport.
+     */
+    public PingRequest (Transport transport)
+    {
+        _transport = transport;
+    }
+
     /**
      * Returns a timestamp that was obtained when this packet was encoded
      * by the low-level networking code.
@@ -85,9 +93,21 @@ public class PingRequest extends UpstreamMessage
         in.defaultReadObject();
     }
 
+    @Override // documentation inherited
+    public void setTransport (Transport transport)
+    {
+        _transport = transport;
+    }
+
+    @Override // documentation inherited
+    public Transport getTransport ()
+    {
+        return _transport;
+    }
+
     public String toString ()
     {
-        return "[type=PING, msgid=" + messageId + "]";
+        return "[type=PING, msgid=" + messageId + ", transport=" + _transport + "]";
     }
 
     /** A time stamp obtained when we serialize this object. */
@@ -97,4 +117,7 @@ public class PingRequest extends UpstreamMessage
      * is to get a timestamp as close as possible to when the packet was
      * received on the network). */
     protected transient long _unpackStamp;
+
+    /** The transport parameters. */
+    protected transient Transport _transport = Transport.DEFAULT;
 }

src/java/com/threerings/presents/net/PongResponse.java

@@ -42,11 +42,12 @@ public class PongResponse extends DownstreamMessage
      * Constructs a pong response which will use the supplied ping time to
      * establish the end-to-end processing delay introduced by the server.
      */
-    public PongResponse (long pingStamp)
+    public PongResponse (long pingStamp, Transport transport)
     {
         // save this for when we are serialized in preparation for
         // delivery over the network
         _pingStamp = pingStamp;
+        _transport = transport;
     }
 
     /**
@@ -112,9 +113,21 @@ public class PongResponse extends DownstreamMessage
         in.defaultReadObject();
     }
 
+    @Override // documentation inherited
+    public void setTransport (Transport transport)
+    {
+        _transport = transport;
+    }
+
+    @Override // documentation inherited
+    public Transport getTransport ()
+    {
+        return _transport;
+    }
+
     public String toString ()
     {
-        return "[type=PONG, msgid=" + messageId + "]";
+        return "[type=PONG, msgid=" + messageId + ", transport=" + _transport + "]";
     }
 
     /** The ping unpack stamp provided at construct time to this pong
@@ -135,4 +148,7 @@ public class PongResponse extends DownstreamMessage
      * is to get a timestamp as close as possible to when the packet was
      * received on the network). */
     protected transient long _unpackStamp;
+
+    /** The transport parameters. */
+    protected transient Transport _transport = Transport.DEFAULT;
 }

src/java/com/threerings/presents/net/Transport.java

@@ -0,0 +1,256 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2008 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.presents.net;
+
+import java.util.EnumMap;
+
+import com.samskivert.util.HashIntMap;
+
+/**
+ * Message transport parameters.  These include the type of transport and the channel (used to
+ * define independent streams for ordered transport), and may eventually include message
+ * priority, etc.
+ */
+public class Transport
+{
+    /**
+     * The available types of transport.
+     */
+    public enum Type
+    {
+        /**
+         * Messages are neither guaranteed to arrive nor, if they do arrive, to arrive in order
+         * and without duplicates.  Functionally identical to UDP.
+         */
+        UNRELIABLE_UNORDERED(false, false) {
+            public Type combine (Type other) {
+                return other; // we defer to all
+            }
+        },
+
+        /**
+         * Messages are not guaranteed to arrive, but if they do arrive, then they will arrive in
+         * order and without duplicates.  In other words, out-of-order packets will be dropped.
+         */
+        UNRELIABLE_ORDERED(false, true) {
+            public Type combine (Type other) {
+                return other.isReliable() ? RELIABLE_ORDERED : this;
+            }
+        },
+
+        /**
+         * Messages are guaranteed to arrive eventually, but they are not guaranteed to arrive in
+         * order.
+         */
+        RELIABLE_UNORDERED(true, false) {
+            public Type combine (Type other) {
+                return other.isOrdered() ? RELIABLE_ORDERED : this;
+            }
+        },
+
+        /**
+         * Messages are guaranteed to arrive, and will arrive in the order in which they are sent.
+         * Functionally identical to TCP.
+         */
+        RELIABLE_ORDERED(true, true) {
+            public Type combine (Type other) {
+                return this; // we override all
+            }
+        };
+
+        /**
+         * Checks whether this transport type guarantees that messages will be delivered.
+         */
+        public boolean isReliable ()
+        {
+            return _reliable;
+        }
+
+        /**
+         * Checks whether this transport type guarantees that messages will be received in the
+         * order in which they were sent, if they are received at all.
+         */
+        public boolean isOrdered ()
+        {
+            return _ordered;
+        }
+
+        /**
+         * Returns a transport type that combines the requirements of this type with those of the
+         * specified other type.
+         */
+        public abstract Type combine (Type other);
+
+        Type (boolean reliable, boolean ordered)
+        {
+            _reliable = reliable;
+            _ordered = ordered;
+        }
+
+        protected boolean _reliable, _ordered;
+    }
+
+    /** The unreliable/unordered mode of transport. */
+    public static final Transport UNRELIABLE_UNORDERED = getInstance(Type.UNRELIABLE_UNORDERED);
+
+    /** The unreliable/ordered mode on the default channel. */
+    public static final Transport UNRELIABLE_ORDERED = getInstance(Type.UNRELIABLE_ORDERED, 0);
+
+    /** The reliable/unordered mode. */
+    public static final Transport RELIABLE_UNORDERED = getInstance(Type.RELIABLE_UNORDERED);
+
+    /** The reliable/ordered mode on the default channel. */
+    public static final Transport RELIABLE_ORDERED = getInstance(Type.RELIABLE_ORDERED, 0);
+
+    /** The default mode of transport. */
+    public static final Transport DEFAULT = RELIABLE_ORDERED;
+
+    /**
+     * Returns the shared instance with the specified parameters.
+     */
+    public static Transport getInstance (Type type)
+    {
+        return getInstance(type, 0);
+    }
+
+    /**
+     * Returns the shared instance with the specified parameters.
+     */
+    public static Transport getInstance (Type type, int channel)
+    {
+        // were there more parameters in transport objects, it would be better to have a single map
+        // of instances and use Transport objects as keys (as in examples of the flyweight
+        // pattern).  however, doing it this way avoids the need to create a new object on lookup
+        if (_unordered == null) {
+            _unordered = new EnumMap<Type, Transport>(Type.class);
+            _ordered = new EnumMap<Type, HashIntMap<Transport>>(Type.class);
+        }
+
+        // for unordered transport, we map on the type alone
+        if (!type.isOrdered()) {
+            Transport instance = _unordered.get(type);
+            if (instance == null) {
+                _unordered.put(type, instance = new Transport(type));
+            }
+            return instance;
+        }
+
+        // for ordered transport, we map on the type and channel
+        HashIntMap<Transport> instances = _ordered.get(type);
+        if (instances == null) {
+            _ordered.put(type, instances = new HashIntMap<Transport>());
+        }
+        Transport instance = instances.get(channel);
+        if (instance == null) {
+            instances.put(channel, instance = new Transport(type, channel));
+        }
+        return instance;
+    }
+
+    /**
+     * Returns the type of transport.
+     */
+    public Type getType ()
+    {
+        return _type;
+    }
+
+    /**
+     * Returns the transport channel.
+     */
+    public int getChannel ()
+    {
+        return _channel;
+    }
+
+    /**
+     * Checks whether this transport guarantees that messages will be delivered.
+     */
+    public boolean isReliable ()
+    {
+        return _type.isReliable();
+    }
+
+    /**
+     * Checks whether this transport guarantees that messages will be received in the order in
+     * which they were sent, if they are received at all.
+     */
+    public boolean isOrdered ()
+    {
+        return _type.isOrdered();
+    }
+
+    /**
+     * Returns a transport that satisfies the requirements of this and the specified other
+     * transport.
+     */
+    public Transport combine (Transport other)
+    {
+        // if the channels are different, we fall back to the default channel
+        return getInstance(
+            _type.combine(other._type),
+            (_channel == other._channel) ? _channel : 0);
+    }
+
+    @Override // documentation inherited
+    public int hashCode ()
+    {
+        return 31*_type.hashCode() + _channel;
+    }
+
+    @Override // documentation inherited
+    public boolean equals (Object other)
+    {
+        Transport otrans;
+        return other instanceof Transport && (otrans = (Transport)other)._type == _type &&
+            otrans._channel == _channel;
+    }
+
+    @Override // documentation inherited
+    public String toString ()
+    {
+        return "[type=" + _type + ", channel=" + _channel + "]";
+    }
+
+    protected Transport (Type type)
+    {
+        this(type, 0);
+    }
+
+    protected Transport (Type type, int channel)
+    {
+        _type = type;
+        _channel = channel;
+    }
+
+    /** The type of transport. */
+    protected Type _type;
+
+    /** The transport channel. */
+    protected int _channel;
+
+    /** Unordered instances mapped by type. */
+    protected static EnumMap<Type, Transport> _unordered;
+
+    /** Ordered instances mapped by type and channel. */
+    protected static EnumMap<Type, HashIntMap<Transport>> _ordered;
+}

src/java/com/threerings/presents/net/UpstreamMessage.java

@@ -21,14 +21,12 @@
 
 package com.threerings.presents.net;
 
-import com.threerings.io.SimpleStreamableObject;
-
 /**
  * This class encapsulates a message in the distributed object protocol
  * that flows from the client to the server.  Upstream messages include
  * object subscription, event forwarding and session management.
  */
-public abstract class UpstreamMessage extends SimpleStreamableObject
+public abstract class UpstreamMessage extends Message
 {
     /**
      * This is a unique (within the context of a reasonable period of
@@ -41,12 +39,6 @@ public abstract class UpstreamMessage extends SimpleStreamableObject
     /** A timestamp indicating when this upstream message was received. */
     public transient long received;
 
-    /**
-     * When sending, this acts as a hint that the message may be transmitted as a datagram.
-     * When receiving, it indicates that the message was received as a datagram.
-     */
-    public transient boolean datagram;
-
     /**
      * Each upstream message derived class must provide a zero argument
      * constructor so that it can be unserialized when read from the

src/java/com/threerings/presents/server/InvocationManager.java

@@ -42,6 +42,8 @@ import com.threerings.presents.dobj.InvocationRequestEvent;
 import com.threerings.presents.dobj.ObjectAccessException;
 import com.threerings.presents.dobj.RootDObjectManager;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * The invocation services provide client to server invocations (service requests) and server to
  * client invocations (responses and notifications). Via this mechanism, the client can make
@@ -183,7 +185,7 @@ public class InvocationManager
     /**
      * Get the class that is being used to dispatch the specified
      * invocation code, for informational purposes.
-     * 
+     *
      * @return the Class, or null if no dispatcher is registered with
      * the specified code.
      */
@@ -201,7 +203,7 @@ public class InvocationManager
         if (event instanceof InvocationRequestEvent) {
             InvocationRequestEvent ire = (InvocationRequestEvent)event;
             dispatchRequest(ire.getSourceOid(), ire.getInvCode(),
-                            ire.getMethodId(), ire.getArgs());
+                            ire.getMethodId(), ire.getArgs(), ire.getTransport());
         }
     }
 
@@ -211,7 +213,7 @@ public class InvocationManager
      * registered invocation dispatcher.
      */
     protected void dispatchRequest (
-        int clientOid, int invCode, int methodId, Object[] args)
+        int clientOid, int invCode, int methodId, Object[] args, Transport transport)
     {
         // make sure the client is still around
         ClientObject source = (ClientObject)_omgr.getObject(clientOid);
@@ -243,6 +245,7 @@ public class InvocationManager
             if (arg instanceof ListenerMarshaller) {
                 ListenerMarshaller list = (ListenerMarshaller)arg;
                 list.omgr = _omgr;
+                list.transport = transport;
                 // keep track of the listener we'll inform if anything
                 // goes horribly awry
                 if (rlist == null) {

src/java/com/threerings/presents/server/InvocationSender.java

@@ -28,6 +28,8 @@ import com.threerings.presents.client.InvocationReceiver.Registration;
 import com.threerings.presents.data.ClientObject;
 import com.threerings.presents.dobj.InvocationNotificationEvent;
 
+import com.threerings.presents.net.Transport;
+
 /**
  * Provides basic functionality used by all invocation sender classes.
  */
@@ -39,6 +41,16 @@ public abstract class InvocationSender
      */
     public static void sendNotification (
         ClientObject target, String receiverCode, int methodId, Object[] args)
+    {
+        sendNotification(target, receiverCode, methodId, args, Transport.DEFAULT);
+    }
+
+    /**
+     * Requests that the specified invocation notification be packaged up and sent to the supplied
+     * target client.
+     */
+    public static void sendNotification (
+        ClientObject target, String receiverCode, int methodId, Object[] args, Transport transport)
     {
         // convert the receiver hash id into the code used on this
         // specific client
@@ -55,7 +67,8 @@ public abstract class InvocationSender
 
             // create and dispatch an invocation notification event
             target.postEvent(
-                new InvocationNotificationEvent(target.getOid(), rreg.receiverId, methodId, args));
+                new InvocationNotificationEvent(
+                    target.getOid(), rreg.receiverId, methodId, args, transport));
         }
     }
 }

src/java/com/threerings/presents/server/PresentsClient.java

@@ -267,7 +267,7 @@ public class PresentsClient
      * does it in the existing client object. Care must be taken to ensure that any client or
      * server code either doesn't map things based on username before this call, or that it's
      * updated to reflect the change.
-     * 
+     *
      * @return - true if the client was successfully renamed, false otherwise
      */
     public boolean updateUsername (Name username)
@@ -978,11 +978,9 @@ public class PresentsClient
     {
         public void dispatch (PresentsClient client, UpstreamMessage msg)
         {
-            // send a pong response
+            // send a pong response using the transport with which the message was received
             PingRequest req = (PingRequest)msg;
-            PongResponse resp = new PongResponse(req.getUnpackStamp());
+            client.safePostMessage(new PongResponse(req.getUnpackStamp(), req.getTransport()));
-            resp.datagram = req.datagram;
-            client.safePostMessage(resp);
         }
     }
 

src/java/com/threerings/presents/server/net/Connection.java

@@ -376,7 +376,6 @@ public abstract class Connection implements NetEventHandler
                 return; // received out of order
             }
             msg.received = when;
-            msg.datagram = true;
             _handler.handleMessage(msg);
 
         } catch (ClassNotFoundException cnfe) {

src/java/com/threerings/presents/server/net/ConnectionManager.java

@@ -850,7 +850,7 @@ public class ConnectionManager extends LoopingThread
 
         try {
             // send it as a datagram if hinted and possible
-            if (msg.datagram && conn.getDatagramAddress() != null) {
+            if (!msg.getTransport().isReliable() && conn.getDatagramAddress() != null) {
                 postDatagram(conn, msg);
                 return;
             }

src/java/com/threerings/presents/tools/GenDObjectTask.java

@@ -46,6 +46,7 @@ import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang.StringUtils;
 
+import org.apache.tools.ant.AntClassLoader;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
 import org.apache.tools.ant.Task;
@@ -61,6 +62,9 @@ import com.samskivert.util.SortableArrayList;
 import com.samskivert.util.StringUtil;
 import com.samskivert.velocity.VelocityUtil;
 
+import com.threerings.presents.annotation.TransportHint;
+import com.threerings.presents.net.Transport;
+
 import com.threerings.presents.dobj.DObject;
 import com.threerings.presents.dobj.DSet;
 import com.threerings.presents.dobj.OidList;
@@ -85,6 +89,11 @@ public class GenDObjectTask extends Task
     {
         _cloader = ClasspathUtils.getClassLoaderForPath(
             getProject(), pathref);
+
+        // set the parent of the classloader to be the classloader used to load this task,
+        // rather than the classloader used to load Ant, so that we have access to Narya
+        // classes like TransportHint
+        ((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
     }
 
     /** Performs the actual work of the task. */
@@ -107,6 +116,7 @@ public class GenDObjectTask extends Task
             _doclass = _cloader.loadClass(DObject.class.getName());
             _dsclass = _cloader.loadClass(DSet.class.getName());
             _olclass = _cloader.loadClass(OidList.class.getName());
+
         } catch (Exception e) {
             throw new BuildException("Can't resolve InvocationListener", e);
         }
@@ -198,6 +208,18 @@ public class GenDObjectTask extends Task
             ctx.put("capfield", StringUtil.unStudlyName(fname).toUpperCase());
             ctx.put("upfield", StringUtils.capitalize(fname));
 
+            // determine the type of transport
+            TransportHint hint = f.getAnnotation(TransportHint.class);
+            String transport;
+            if (hint == null) {
+                transport = "DEFAULT";
+            } else {
+                transport = "getInstance(\n" +
+                    "                com.threerings.presents.net.Transport.Type." +
+                        hint.type().name() + ", " + hint.channel() + ")";
+            }
+            ctx.put("transport", "com.threerings.presents.net.Transport." + transport);
+
             // if this field is an array, we need its component types
             if (ftype.isArray()) {
                 Class<?> etype = ftype.getComponentType();

src/java/com/threerings/presents/tools/GenReceiverTask.java

@@ -38,6 +38,7 @@ import com.samskivert.util.StringUtil;
 
 import com.threerings.presents.client.InvocationDecoder;
 import com.threerings.presents.data.ClientObject;
+import com.threerings.presents.net.Transport;
 import com.threerings.presents.server.InvocationSender;
 
 /**
@@ -85,7 +86,7 @@ public class GenReceiverTask extends InvocationTask
             methods.add(new ServiceMethod(m, imports));
         }
         methods.sort();
-        
+
         // get rid of primitives and java.lang types
         imports.removeGlobals();
 
@@ -106,6 +107,7 @@ public class GenReceiverTask extends InvocationTask
         CollectionUtil.addAll(implist, imports);
         checkedAdd(implist, ClientObject.class.getName());
         checkedAdd(implist, InvocationSender.class.getName());
+        checkedAdd(implist, Transport.class.getName());
         String dname = StringUtil.replace(rname, "Receiver", "Decoder");
         checkedAdd(implist, rpackage + "." + dname);
         implist.sort();

src/java/com/threerings/presents/tools/GenServiceTask.java

@@ -39,6 +39,7 @@ import com.threerings.presents.client.InvocationService;
 import com.threerings.presents.data.ClientObject;
 import com.threerings.presents.data.InvocationMarshaller;
 import com.threerings.presents.dobj.InvocationResponseEvent;
+import com.threerings.presents.net.Transport;
 import com.threerings.presents.server.InvocationDispatcher;
 import com.threerings.presents.server.InvocationException;
 import com.threerings.presents.server.InvocationProvider;
@@ -46,11 +47,11 @@ import com.threerings.presents.server.InvocationProvider;
 /**
  * An Ant task for generating invocation service marshalling and
  * unmarshalling classes.
- * TODO: when generating the imports for exported action script files, there are just enough 
+ * TODO: when generating the imports for exported action script files, there are just enough
  * conversions of primitive types (e.g. float -> Number), array types (e.g. int[] -> TypedArray)
  * and three rings utility types (e.g. float -> Float) to make the existing serivces work. It
  * should be possible to create a complete list of these conversions so that future services
- * can be generated without problems. 
+ * can be generated without problems.
  */
 public class GenServiceTask extends InvocationTask
 {
@@ -61,7 +62,7 @@ public class GenServiceTask extends InvocationTask
 
         public ComparableArrayList<ServiceMethod> methods =
             new ComparableArrayList<ServiceMethod>();
-        
+
         /** Contains all imports required for the parameters of the methods in this listener. */
         public ImportSet imports = new ImportSet();
 
@@ -77,12 +78,12 @@ public class GenServiceTask extends InvocationTask
                     continue;
                 }
                 if (_verbose) {
-                    System.out.println("Adding " + m + ", imports are " + 
+                    System.out.println("Adding " + m + ", imports are " +
                         StringUtil.toString(imports));
                 }
                 methods.add(new ServiceMethod(m, imports));
                 if (_verbose) {
-                    System.out.println("Added " + m + ", imports are " + 
+                    System.out.println("Added " + m + ", imports are " +
                         StringUtil.toString(imports));
                 }
             }
@@ -137,7 +138,7 @@ public class GenServiceTask extends InvocationTask
     protected void processService (File source, Class service)
     {
         System.out.println("Processing " + service.getName() + "...");
-        
+
         // verify that the service class name is as we expect it to be
         if (!service.getName().endsWith("Service")) {
             System.err.println("Cannot process '" + service.getName() + "':");
@@ -167,7 +168,7 @@ public class GenServiceTask extends InvocationTask
             sdesc.spackage, ".client", ".data");
 
         // ----------- Part I - java marshaller
-        
+
         // start with all imports (service methods and listener methods)
         ImportSet imports = sdesc.constructAllImports();
 
@@ -175,30 +176,31 @@ public class GenServiceTask extends InvocationTask
         imports.add(sdesc.service);
         imports.add(Client.class);
         imports.add(InvocationMarshaller.class);
+        imports.add(Transport.class);
 
         // if any listeners are to be present, they need the response event
         if (sdesc.listeners.size() > 0) {
             imports.add(InvocationResponseEvent.class);
         }
-        
+
         // import classes contained in arrays
         imports.translateClassArrays();
-        
+
         // get rid of java.lang stuff and primitives
         imports.removeGlobals();
-        
+
         // get rid of all arrays (they are automatic in java)
         imports.removeArrays();
-        
+
         // for each listener type, also import the corresponding marshaller
-        imports.duplicateAndMunge("*Listener", 
+        imports.duplicateAndMunge("*Listener",
             "Service", "Marshaller",
             "Listener", "Marshaller",
             ".client.", ".data.");
 
         // import the parent class of Foo$Bar
         imports.swapInnerClassesForParents();
-        
+
         // remove imports in our own package
         imports.removeSamePackage(mpackage);
 
@@ -234,15 +236,15 @@ public class GenServiceTask extends InvocationTask
 
         // start with the service method imports
         imports = sdesc.imports.clone();
-        
+
         // add some things that marshallers just need
         imports.add(sdesc.service);
         imports.add(Client.class);
         imports.add(InvocationMarshaller.class);
-        
+
         // replace inner classes with action script equivalents
         imports.translateInnerClasses();
-        
+
         // replace primitive types with OOO types (required for unboxing)
         imports.replace("byte", "com.threerings.util.Byte");
         imports.replace("int", "com.threerings.util.Integer");
@@ -268,7 +270,7 @@ public class GenServiceTask extends InvocationTask
 
         // get rid of java.lang stuff and any remaining primitives
         imports.removeGlobals();
-        
+
         if (imports.removeAll("[L*") > 0) {
             imports.add("com.threerings.io.TypedArray");
         }
@@ -304,20 +306,20 @@ public class GenServiceTask extends InvocationTask
 
                 // start imports with just those used by listener methods
                 imports = listener.imports.clone();
-                
+
                 // always need the super class and the listener class
                 imports.add(imlm);
                 imports.add(listener.listener);
-                
+
                 // replace '$' with '_' for action script naming convention
                 imports.translateInnerClasses();
-                
+
                 // convert primitive java types to ooo util types
                 imports.replace("long", "com.threerings.util.Long");
 
                 // get rid of remaining primitives and java.lang types
                 imports.removeGlobals();
-                
+
                 // remove imports in our own package
                 imports.removeSamePackage(mpackage);
 
@@ -359,7 +361,7 @@ public class GenServiceTask extends InvocationTask
 
         // get rid of primitives and java.lang classes
         imports.removeGlobals();
-        
+
         // get rid of remaining arrays
         imports.removeArrays();
 
@@ -394,20 +396,20 @@ public class GenServiceTask extends InvocationTask
 
                 // start with just the imports needed by listener methods
                 imports = listener.imports.clone();
-                
+
                 // add things needed by all listeners
                 imports.add(isil);
                 imports.add(listener.listener);
-                
+
                 // change Foo$Bar to Foo_Bar
                 imports.translateInnerClasses();
-                
+
-                // convert java primitive types to ooo util types 
+                // convert java primitive types to ooo util types
                 imports.replace("long", "com.threerings.util.Long");
-                
+
                 // get rid of remaining primitives and java.lang types
                 imports.removeGlobals();
-                
+
                 // remove imports in our own package
                 imports.removeSamePackage(sdesc.spackage);
 
@@ -450,29 +452,29 @@ public class GenServiceTask extends InvocationTask
         // swap Client for ClientObject
         imports.add(ClientObject.class);
         imports.remove(Client.class);
-        
+
         // add some classes required for all dispatchers
         imports.add(InvocationMarshaller.class);
         imports.add(InvocationDispatcher.class);
         imports.add(InvocationException.class);
-        
+
         // import classes contained in arrays
         imports.translateClassArrays();
-        
+
         // get rid of primitives and java.lang types
         imports.removeGlobals();
-        
+
         // get rid of arrays
         imports.removeArrays();
 
         // import the Marshaller corresponding to the service
-        imports.addMunged(sdesc.service, 
+        imports.addMunged(sdesc.service,
             "Service", "Marshaller",
             ".client.", ".data.");
 
         // import Foo instead of Foo$Bar
         imports.swapInnerClassesForParents();
-        
+
         // remove imports in our own package
         imports.removeSamePackage(dpackage);
 
@@ -504,7 +506,7 @@ public class GenServiceTask extends InvocationTask
         if (_verbose) {
             System.out.println("Generating provider");
         }
-        
+
         String name = StringUtil.replace(sdesc.sname, "Service", "");
         String mpackage = StringUtil.replace(
             sdesc.spackage, ".client", ".server");
@@ -515,24 +517,24 @@ public class GenServiceTask extends InvocationTask
         // swap Client for ClientObject
         imports.add(ClientObject.class);
         imports.remove(Client.class);
-        
+
         // import superclass
         imports.add(InvocationProvider.class);
-        
+
-        // any method that takes a listener may throw this 
+        // any method that takes a listener may throw this
         if (sdesc.hasAnyListenerArgs()) {
             imports.add(InvocationException.class);
         }
-        
+
         // import classes contained in arrays
         imports.translateClassArrays();
-        
+
         // get rid of primitives and java.lang types
         imports.removeGlobals();
-        
+
         // get rid of arrays
         imports.removeArrays();
-        
+
         // import Foo instead of Foo$Bar
         imports.swapInnerClassesForParents();
 
@@ -593,19 +595,19 @@ public class GenServiceTask extends InvocationTask
                     }
                 }
                 if (_verbose) {
-                    System.out.println("Adding " + m + ", imports are " + 
+                    System.out.println("Adding " + m + ", imports are " +
                         StringUtil.toString(imports));
                 }
                 methods.add(new ServiceMethod(m, imports));
                 if (_verbose) {
-                    System.out.println("Added " + m + ", imports are " + 
+                    System.out.println("Added " + m + ", imports are " +
                         StringUtil.toString(imports));
                 }
             }
             listeners.sort();
             methods.sort();
         }
-        
+
         /**
          * Checks if any of the service method arguments are listener types.
          */
@@ -640,7 +642,7 @@ public class GenServiceTask extends InvocationTask
         ComparableArrayList<ServiceListener> listeners =
             new ComparableArrayList<ServiceListener>();
     }
-    
+
     /** The path to our ActionScript source files. */
     protected File _asroot;
 

src/java/com/threerings/presents/tools/InvocationTask.java

@@ -34,6 +34,7 @@ import java.util.List;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 
+import org.apache.tools.ant.AntClassLoader;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
 import org.apache.tools.ant.Task;
@@ -46,6 +47,9 @@ import org.apache.velocity.app.VelocityEngine;
 import com.samskivert.util.StringUtil;
 import com.samskivert.velocity.VelocityUtil;
 
+import com.threerings.presents.annotation.TransportHint;
+import com.threerings.presents.net.Transport;
+
 import com.threerings.presents.client.InvocationService.InvocationListener;
 
 /**
@@ -90,7 +94,7 @@ public abstract class InvocationTask extends Task
         }
     }
 
-    /** Used to keep track of invocation service methods or listener 
+    /** Used to keep track of invocation service methods or listener
      *  methods. */
     public class ServiceMethod implements Comparable<ServiceMethod>
     {
@@ -101,13 +105,13 @@ public abstract class InvocationTask extends Task
 
         /**
          * Creates a new service method.
-         * @param method the method to inspect 
+         * @param method the method to inspect
          * @param imports will be filled with the types required by the method
          */
         public ServiceMethod (Method method, ImportSet imports)
         {
             this.method = method;
-            
+
             // we need to look through our arguments and note any needed
             // imports in the supplied table
             Class<?>[] args = method.getParameterTypes();
@@ -249,6 +253,16 @@ public abstract class InvocationTask extends Task
             return buf.toString();
         }
 
+        public String getTransport ()
+        {
+            TransportHint hint = method.getAnnotation(TransportHint.class);
+            if (hint == null) {
+                return "Transport.DEFAULT";
+            }
+            return "Transport.getInstance(Transport.Type." +
+                hint.type().name() + ", " + hint.channel() + ")";
+        }
+
         protected String boxArgument (Class<?> clazz, int index)
         {
             if (_ilistener.isAssignableFrom(clazz)) {
@@ -306,6 +320,11 @@ public abstract class InvocationTask extends Task
     {
         _cloader = ClasspathUtils.getClassLoaderForPath(
             getProject(), pathref);
+
+        // set the parent of the classloader to be the classloader used to load this task,
+        // rather than the classloader used to load Ant, so that we have access to Narya
+        // classes like TransportHint
+        ((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
     }
 
     /** Performs the actual work of the task. */
@@ -405,7 +424,7 @@ public abstract class InvocationTask extends Task
 
     /** Show extra output if set. */
     protected boolean _verbose;
-    
+
     /** Used to do our own classpath business. */
     protected ClassLoader _cloader;
 

src/java/com/threerings/presents/tools/dobject_field.tmpl

@@ -10,7 +10,8 @@
     {
         $type ovalue = this.$field;
         requestAttributeChange(
-            $capfield, $wrapfield, $wrapofield);
+            $capfield, $wrapfield, $wrapofield,
+            $transport);
         this.$field = $clonefield;
     }
 #if ($elemtype)
@@ -28,7 +29,8 @@
     {
         $elemtype ovalue = this.$field[index];
         requestElementUpdate(
-            $capfield, index, $wrapelem, $wrapoelem);
+            $capfield, index, $wrapelem, $wrapoelem,
+            $transport);
         this.$field[index] = value;
     }
 #end

src/java/com/threerings/presents/tools/dobject_set.tmpl

@@ -25,7 +25,9 @@
      */
     public void update$upfield ($etype elem)
     {
-        requestEntryUpdate($capfield, $field, elem);
+        requestEntryUpdate(
+            $capfield, $field, elem,
+            $transport);
     }
 
     /**

src/java/com/threerings/presents/tools/marshaller.tmpl

@@ -32,7 +32,7 @@ public class ${name}Marshaller extends InvocationMarshaller
             _invId = null;
             omgr.postEvent(new InvocationResponseEvent(
                                callerOid, requestId, $lm.code,
-                               new Object[] { $lm.getWrappedArgList(false) }));
+                               new Object[] { $lm.getWrappedArgList(false) }, transport));
         }
 
 #end
@@ -71,7 +71,7 @@ public class ${name}Marshaller extends InvocationMarshaller
 #end
         sendRequest(arg1, $m.code, new Object[] {
             $m.getWrappedArgList(true)
-        });
+        }, $m.transport);
     }
 #end
 }

src/java/com/threerings/presents/tools/sender.tmpl

@@ -20,7 +20,7 @@ public class ${name}Sender extends InvocationSender
     {
         sendNotification(
             target, ${name}Decoder.RECEIVER_CODE, ${name}Decoder.$m.code,
-            new Object[] { $m.getWrappedArgList(false) });
+            new Object[] { $m.getWrappedArgList(false) }, $m.transport);
     }
 
 #end

src/java/com/threerings/presents/util/DatagramSequencer.java

@@ -30,6 +30,9 @@ import java.util.Set;
 import com.threerings.io.UnreliableObjectInputStream;
 import com.threerings.io.UnreliableObjectOutputStream;
 
+import com.threerings.presents.net.Message;
+import com.threerings.presents.net.Transport;
+
 /**
  * Used on both the client and the server to handle the encoding and decoding of sequenced
  * datagrams.
@@ -48,7 +51,7 @@ public class DatagramSequencer
     /**
      * Writes a datagram to the underlying stream.
      */
-    public synchronized void writeDatagram (Object datagram)
+    public synchronized void writeDatagram (Message datagram)
         throws IOException
     {
         // first write the sequence and acknowledge numbers
@@ -79,7 +82,7 @@ public class DatagramSequencer
      * @return the contents of the datagram, or <code>null</code> if the datagram was received
      * out-of-order.
      */
-    public synchronized Object readDatagram ()
+    public synchronized Message readDatagram ()
         throws IOException, ClassNotFoundException
     {
         // read in the sequence number and determine if it's out-of-order
@@ -104,8 +107,10 @@ public class DatagramSequencer
         }
         _sendrecs.subList(0, remove).clear();
 
-        // read and return the contents of the datagram
+        // read the contents of the datagram, note the transport, and return
-        return _uin.readObject();
+        Message datagram = (Message)_uin.readObject();
+        datagram.setTransport(Transport.UNRELIABLE_ORDERED);
+        return datagram;
     }
 
     /**