Finally incorporated Par's Enum streaming support, modified to use the string

value to avoid future compatibility problems if someone saves an object to a
database and then later adds a new enum anywhere but at the end of the list,
thereby changing the ordinals.

If you want maximal network efficiency, don't use enums. For most of what we'll
do with them, it doesn't merit having the future incompatibility hitch of
sending the ordinal.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4369 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/io/Streamer.java

@@ -64,15 +64,19 @@ public class Streamer
                 return true;
             }
 
-            // if it's an array, check the component type
-            if (target.isArray()) {
-                target = target.getComponentType();
-                // and loop back around for another check with the comp type...
+            // enums can be streamed
+            if (target.isEnum()) {
+                return true;
+            }
 
-            } else {
-                // it'll be ok if the type (or component type) is Streamable
+            // if it's not an array, it must be streamable
+            if (!target.isArray()) {
                 return Streamable.class.isAssignableFrom(target);
             }
+
+            // otherwise extract the component type and loop back around for
+            // another check...
+            target = target.getComponentType();
         }
     }
 
@@ -197,6 +201,14 @@ public class Streamer
             return;
         }
 
+        // if we're writing an enum; write its string value (to avoid future
+        // compatibility issues if someone serializes an enum to a file and
+        // then adds a value to the enum, changing the ordinal assignments)
+        if (_target.isEnum()) {
+            out.writeUTF(((Enum)object).name());
+            return;
+        }
+
         // otherwise simply write out the fields via our field marshallers
         int fcount = _fields.length;
         for (int ii = 0; ii < fcount; ii++) {
@@ -245,6 +257,16 @@ public class Streamer
                              "[" + length + "]'.");
                 }
                 return Array.newInstance(_target.getComponentType(), length);
+
+            } else if (_target.isEnum()) {
+                if (ObjectInputStream.STREAM_DEBUG) {
+                    log.info(in.hashCode() + ": Creating enum '" +
+                             _target.getName() + "'.");
+                }
+                @SuppressWarnings("unchecked") Object value = 
+                    Enum.valueOf(_target, in.readUTF());
+                return value;
+
             } else {
                 if (ObjectInputStream.STREAM_DEBUG) {
                     log.info(in.hashCode() + ": Creating object '" +
@@ -347,6 +369,11 @@ public class Streamer
             return;
         }
 
+        // an enum has no additional state
+        if (_target.isEnum()) {
+            return;
+        }
+
         // otherwise simply read the fields via our field marshallers
         int fcount = _fields.length;
         for (int ii = 0; ii < fcount; ii++) {