public <T extends Enum<T>> boolean registerEnum(Class<T> enumClass)
    {
        return null == enumMapping.putIfAbsent(enumClass.getName(),
                EnumIO.newEnumIO(enumClass, this));
    }
Registers an enum. Returns true if registration is successful.
protostuff-runtime/src/main/java/io/protostuff/runtime/DefaultIdStrategy.java