Handle parameterized types in invocation services and receivers.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@6232 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/main/java/com/threerings/presents/server/InvocationDispatcher.java

@@ -49,4 +49,13 @@ public abstract class InvocationDispatcher<T extends InvocationMarshaller>
         log.warning("Requested to dispatch unknown method", "provider", provider,
                     "sourceOid", source.getOid(), "methodId", methodId, "args", args);
     }
+
+    /**
+     * Performs type casts in a way that works for parameterized types as well as simple types.
+     */
+    @SuppressWarnings("unchecked")
+    protected <T> T cast (Object value)
+    {
+        return (T)value;
+    }
 }