Determined that we need to pass the field type into the fromPersistent() to

support use cases like ByteEnum. (Even though I'm leaving ByteEnum support
hard-coded for the time being.)

src/java/com/samskivert/depot/Transformer.java

@@ -30,9 +30,23 @@ package com.samskivert.depot;
  */
 public interface Transformer<F,T>
 {
-    /** Transforms a runtime value into a value that can be persisted. */
+    /**
+     * Transforms a runtime value into a value that can be persisted.
+     *
+     * @param value the value just read from a persistent record.
+     *
+     * @return the transformed value, which will be written to the database.
+     */
     T toPersistent (F value);
 
-    /** Transforms a persisted value into a value that can be store in a runtime field. */
+    /**
-    F fromPersistent (T value);
+     * Transforms a persisted value into a value that can be store in a runtime field.
+     *
+     * @param fieldType the type of the persistent record field to which the transformed value will
+     * be written.
+     * @param value the value just read from the database.
+     *
+     * @return the transformed value, which will be stored in a field of the persistent record.
+     */
+    F fromPersistent (Class<?> fieldType, T value);
 }

src/java/com/samskivert/depot/Transformers.java

@@ -33,9 +33,6 @@ import com.samskivert.depot.annotation.Column;
  *     public String[] cities;
  * }
  * </pre>
- * Because of limitations of Java's annotation system, configuration of transformers is not
- * possible (without complex machinations) and separate classes must be created for any particular
- * transformation.
  */
 public class Transformers
 {
@@ -46,7 +43,7 @@ public class Transformers
         public String toPersistent (String[] value) {
             return Joiner.on(",").join(value);
         }
-        public String[] fromPersistent (String value) {
+        public String[] fromPersistent (Class<?> ftype, String value) {
             return value.split(",");
         }
     }