/** * Recursively checks whether the specified class uses any Protocol Buffers fields that cannot be * deterministically encoded. * * @throws NonDeterministicException if the object cannot be encoded deterministically. */ static void verifyDeterministic(ProtoCoder<?> coder) throws NonDeterministicException { Class<? extends Message> message = coder.getMessageType(); ExtensionRegistry registry = coder.getExtensionRegistry(); Set<Descriptor> descriptors = getRecursiveDescriptorsForClass(message, registry); for (Descriptor d : descriptors) { for (FieldDescriptor fd : d.getFields()) { // If there is a transitively reachable Protocol Buffers map field, then this object cannot // be encoded deterministically. if (fd.isMapField()) { String reason = String.format( "Protocol Buffers message %s transitively includes Map field %s (from file %s)." + " Maps cannot be deterministically encoded.", message.getName(), fd.getFullName(), fd.getFile().getFullName()); throw new NonDeterministicException(coder, reason); } } } }