private static void writeUnmodifiableMapTo(Output output, Object value,
            Schema<?> currentSchema, IdStrategy strategy, int id)
            throws IOException
    {
        final Object m;
        try
        {
            m = fUnmodifiableMap_m.get(value);
        }
        catch (IllegalAccessException e)
        {
            throw new RuntimeException(e);
        }
        catch (IllegalArgumentException e)
        {
            throw new RuntimeException(e);
        }

        output.writeObject(id, m, strategy.POLYMORPHIC_MAP_SCHEMA, false);
    }
Used when the type is an interface (Map/SortedMap).

@author David Yu
@created Apr 24, 2012
protostuff-runtime/src/main/java/io/protostuff/runtime/PolymorphicMapSchema.java